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Cells that do not have membrane bound nuclei are called prokaryotic cells. Bacteria, blue-green algae, mycoplasma and PPLO (Pleuro Pneumonia Like Organisms) represent prokaryotic cells.
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Golgi bodies main function is packaging materials which are to be delivered either to the intra-cellular targets or secreted
outside the cell.
Define the following :
1. Nucleoid
2. Eukaryotic cells
3. Cristae
4. Mitochondrial matrix.
1. Nucleoid. It is the open nuclear material of prokaryotes. It is an irregularly shaped region that contains the genetic material of the prokaryotic cell.
2. Eukaryotic cells. The cells in which the nuclear material is enclosed by a definite nuclear membrane are known as eukaryotic cells.
3. Cristae. The infoldings of the inner membrane of mitochondria which look like finger like projections are called cristae.
4. Mitochondrial matrix. It is ground substance present in the space enclosed by the inner mitochondrial membrane. It is also known as nucleoplasm.
1. Avoids duplication of work : Only certain cells perform a specific function. Thus, all cells do not have to perform the same function and there is no waste of energy on duplication of work.
2. Increases chances of survival : Death of a few cells does not affect a multicellular organism. The function is taken by new cells of the same lineage.
3. Makes specialized units highly effective: Diffrent cells perform different function. Cells performing similar functions are grouped into tissue which carry out specific function.
4. Long life : Greater efficiency of the cells, because of division of labour, makes multicellular organisms to live longer.
Following are the disadvantages of multicellularity:
1. Certain specialized cells lose the power of division and cannot be replaced if damaged.
2. Some specialized cells lose basic functions.
3. Multicellualr organism have much complex system.
1. Prokaryotic cells : They are without nuclear membrane.
2. Eukaryotic cells : They possess nuclear membrane.
Discovery of cell : Cell was discovered by Robert Hooke in 1665.
(i) all living organisms are composed of cells and products of cells.
(ii) all cells arise from pre-existing cells.
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Example : Microvilli. These are the evaginations present on epithelial cells like those of ileum. They help to increase the surface area for exchange of materials and absorption.
Diffusion. It is the passing of molecules from higher concentration to lower concentration. F
Importance of diffusion :
It helps in the transport of different materials in and ot of the cell.
1. Permeable membranes. These membranes allow diffusion of both solvent and solute molecules or ions through them e.g. cell wall.
2. Impermeable membranes. These membranes prevent any substance to pass through it.
3. Semipermeable membranes. These types of membranes allow diffusion of certain substances through it while prevent the others to pass through it. e.g. cell membrane.
2. It keeps the cell contents in place and distinct from the environment materials.
3. It helps in the transport of materials in and out of the cell. By controlling flow of materials and information into the cell, the cell membrane makes metabolism possible.
4. It permits the exit of secretions and wastes materials.
5. It protects the cell from mechanical injury and other unfavourable factors.
2. It protects the cells from mechanical injury.
3. It wards off the attacks of pathogens (viruses, bacteria, fungi, protozoans) and protects from infection.
4. It allows the transport of materials in and out of the cell.
5. The cell wall helps in cell to cell interactions.
Cell wall is usually made of cellulose. It may consist of hemicellulose, pectins galactans, mannans, minerals like calcium carbonate and proteins.
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Primary cell wall |
Secondary cell wall |
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1. It is found in young dividing cells. 2. It lies internal to the middle lamella. 3. It is present in all plant cells. 4. It is elastic and capable of expansion in a growing cell. 5. It is thin. 6. It is composed of mainly cellulose and lacks additional material. |
1. It is found in a mature and non dividing cell. 2. It lies internal to the primary wall. 3. It is present in certain cells only. 4. It is rigid and incapable of expansion. 5. It is thick. 6. It has additional materials like hemi-cellulose lignin, suberin etc. |
1. Smooth endoplasmic reticulum (agrannular form). The outer surface of the membranes of such endoplasmic reticulum is smooth and does not bear ribosomes. The smooth endoplasmic reticulum is the major site for synthesis of lipid. In animal cells lipid-like steroidal hormones are synthesised in SER.
2. Rough endoplasmic reticulum (grannular from). bears ribosomes on its surface. Due to the presence of ribosomes the outer surface appears to be grannular or rough. Rough endoplasmic is continuos with the outer membrane of the nucleus. It is found in cells actively engaged in protein synthesis e.g. cells of pancreas, plasma cells, liver cells, goblet cells etc.
The endoplasmic reticulum is the network or of tiny tubular structures scattered in the cytoplasm. The endoplasmic reticulum is generally of two types smooth and rough endoplasmic reticulum. The rough endoplasmic reticulum has ribosomes attached to it whereas the smooth endoplasmic reticulum does not have ribosomes. The rough ER is generally found in cells actively involved in protein synthesis. Lipid synthesis is associated with the smooth endoplasmic reticulum.
A. Smooth endoplasmic reticulum - does not have ribosome.
B. Rough endoplasmic reticulum - has ribosomes attached to it.
A. Functions of smooth endoplasmic reticulum :
1. It is especially prominent in cells which are not involved in the synthesis of lipids.
2. It is involved in the synthesis of Golgi complex, lysosmoes and microbodies.
B. Functions of rough endoplasmic reticulum:
1. It is primarily involved in protein synthesis owing to the presence of ribosomes.
2. Packaging. The proteins manufactured in ribosomes are packed in RER. They are processed and packed in vesicles which are pinched off from RER.
3. Formation of glycoproteins. The carbohydrates and proteins are linked in RER to form glycoproteins.
4. Helps in the formation of nuclear envelops.
Occurrence. The Golgi complex is found in all the eukaryotic cells of plants and animals. However, it is absent in prokaryotic cells. In higher animals it is situated between the nucleus and the cell membrane, while in invertebrates and some specialized cells of vertebrates such as nerve cells, liver cells etc., the Golgi complex is found scattered in the cytoplasm.
In the plant cells the Golgi complex consists of a number of unconnected structures known as dictyosomes. Hundreds of such dictyosomes are found scattered in the cytoplasm.
Structure - If observed under electron microscope the Golgi complex consists of the following components :
1. Cisternae. These are the tubular or flattened fluid filled sacs. The Golgi cisternae are concentrically arranged near the nucleus with distinct convex cis or the forming face and concave trans or the maturing face.
2. Vesicles. These are small drop-like structures associated with convex surface of the Golgi complex.
3. Tubules. These are branched structures which arise from periphery of cisternae.
4. Vacuoles. These are present on the sides and on the maturing surface of the Golgi complex. These are formed by the pinching of the cisternae of the Golgi complex. The vacuoles are filled with amorphous or granular substances.
1. It performs the function of packaging the material, delivering them to the target cells and in secretion. Materials to be packaged in the form of vesicles from the ER fuse with the cis face of the golgi apparatus and move towards trans face.
2. A number of proteins synthesised by ribosomes on the endoplasmic reticulum are modified by the golgi bodies before being released
3.Golgi apparatus is the important site of formation of glycoproteins and glycolipids.
Location. The ribosomes are the only organelles which are universally found in all cells i.e. prokaryotic and eukaryotic cells. In prokaryotic cells they are found freely floating in the cytoplasm, while in eukaryotic cells they are are usually found attached at the outer surface of endoplasmic reticulum.
Shape and size. They are oblate spheroidal in form and have size of 18nm in bacteria, chloroplasts and mitochondria and 30 nm in eukaryotic cell.
Types. Ribosomes are of two basic types, 70S and 80S ribosomes. The ‘S’ refers to Svedberg units . 80S ribosomes are found in eukaryotes. while the 70S is found in prokaryotes. The 70S ribosome is has 50S and 30S units whereas 80S is made up of 60S and 40S units.
1. They help in the digestion of proteins, carbohydrates and lipids as they possess hydrolytic enzmes like proteases, carbohydrases and lipases.
2.Cellular digestion. When a cell dies during the pathological conditions or when a cell grows old due to natural ageing, the lysomes help in the digestion and removal of such cells.
Functions of mitochondria are :
1. Mitochondria are the power houses of the cell. they produce cellular energy in form of ATP.
2. They are the sites for aerobic respiration.
3. They possess single circular DNA molecule, RNA, ribosomes and other material for the synthesis of proteins.
1. They have DNA, RNA, ribosomes and other materials required to synthesize their own essential proteins.
2. They manufacture their own enzymes.
3. They can multiply and give rise to new organelles of the same kind. .
1. They form the basal body of cilia and flagella.
2. The form spindle fibres during the cell division which helps the chromosomes to divide equally.
The major function of cilia and flagella is to help in the locomotion and movemnet of the cells. Cilia are shorter and acts like oars causing the movement of the cell or the surrounding medium around it. Flagella are longer as compared to cilia and are responsible for the movement of the cell.
The nuclear envelope performs the following functions :
1. It maintains the shape of the nucleus.
2. It keeps the nuclear contents in place and distinct from the cytoplasm.
3. It regulates the flow of materials into and out of the nucleus by active transport and outpocketing.
4. Its pores allow the exit of ribosomal subunits.
Functions of nuclear matrix :
1. It maintains the shape of the nucleus.
2. Chromatin fibres are anchored to nuclear matrix.
3. The machinery for various nuclear activities such as transcription and replication is associated with the matrix.
Functions of nucleolus :
1. It is the site for rRNA synthesis.
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Gram +ve bacteria |
Gram -ve bacteria |
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1. They remain coloured blue or purple with Gram stain even after washing with absolute alcohol or acetone. 2. The cell wall is 100-200A thick, single layered. 3. The bacteria are less resistant to antibiotics. 4. They are mostly non-pathogenic.
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1. They don't retain the stain when washed with absolute alcohol. 2. The cell wall is 70-120Å thick, two layered. 3.They are more resistant to antibiotics. 4. They are mostly pathogenic.
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Pili |
Fimbriae |
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1. These are elongate tubular structures. 2. They are present mainly in Gram -ve bacteria. 3. They are involved in mating process and form conjugation tube. 4. These are not responsible in connecting cells. |
1. These are small bristle like fibres. 2. They are present both in Gram +ve and Gram -ve bacteria. 3. They have no role in mating. 4. These are responsible for connecting cells. |
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Prokaryotic cells |
Eukaryotic cells |
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1. They have no nuclear membrane. Thus well defined nucleus is absent. They have nucleoid. 2. Nucleolus is absent. 3. They have one chromosome. 4. No histone protein around DNA. 5. Ribosomes are of 70S. 7. No streaming movement of cytoplasm. 8. E.R. is absent. 9. Mitochondria is absent. 10. Golgi apparatus is absent. 11. Lysosomes are absent. 12. Respiratory enzymes are attached at innerside of plasmalemma. 13. Mesosomes may be present.
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1. They have well defined nucleus bounded by double nuclear membrane. 2. Nucleolus is present. 3. They have a number of chromosomes. 4. Histone protein is present around DNA. 5. Ribosomes are of 80S. 7. Cytoplasm exhibits streaming movements. 8. E.R. is present. 9. Mitochondria is present. 10. Golgi apparatus is present. 11. Lysosomes are present. 12. Respiratory enzymes are present in mitochondria.
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Chloroplasts |
Mitochondria |
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1. They have thylakoids. 2. They have green pigments. 3. They are present only in green cells.
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1. They have cristae. 2. No pigments. 3. They are present in all eukaryotic cells.
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Cilia |
Flagella |
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1. They are 2-10nm in length. 2. They are hair-like. 3. Their number per cell is relatively large. 4. They usually cover the entire exposed surface of the cell. 5. They beat in co-ordinated manner. 6. They exhibit sweeping or rowing motion. 7. The ciliary locomotion is fast. |
1. They reach a length upto 150nm. 2. They are whip like. 3. Their number per cell is relatively small, usually 1-4. 4. They are present at one end only. 5. They beat independently. 6. They show undulating motion. 7. The flagellar locomotion is slow. |
| A. Cristae | (i) Flat membranous sacs in stroma |
| B. Cisternae | (ii) Infoldings in mitochondria |
| C. Thylakoids | (iii) Disc-shaped sacs in Golgi apparatus. |
A. Cristae | (i) Infoldings in mitochondria |
B. Cisternae | (ii) Disc-shaped sacs in Golgi apparatus. |
C. Thylakoids | (iii) Flat membranous sacs in stroma |
Mesosome is a specialised membranous structure formed by the invagination of plasma membrane in prokaryotes. These extensions are
in the form of vesicles, tubules and lamellae.
The mesosome performs the following functions -:
1. Help in respiration, secretion processes by increasing the surface area of the plasma membrane and enzymatic content.
2. Helps in DNA replication and distribution to daughter cells.
4. Help in cell wall formation.
Characteristics of Prokaryotic cell are as follows:
1. The nucleus is not bounded by a membrane.
2. Their genetic material is naked and present in the form of nucleoid in the cytoplasm.
3. They are generally smaller and divide more rapidly as compared to the eukaryotic cell.
4. They are usually surrounded by cell wall except for mycoplasma.
5. Besides genomic DNA many prokaryotic cell have small circular DNA called plasmids outside the genomic DNA.
6. Eukaryotic organelles or membrane bound organelles are not found in the prokaryotic cells. The ribosomes found in these are of 70S type.
7. Mesosomes which are the invaginations of plasma membrane may be present.
8. They have special inclusion bodies.
Depending upon the location of centromere in a chromosome, the chromosome is classified into the following four types :
(a) Telocentric: Centromere is present at the terminals.
(b) Acrocentric: Centromere is present near the terminals resulting in two short arms and two long arms.
(c) Sub- metacentric : Centromere divides the chromosomes into two unequal arms. It lies either below centre or above centre.
(d) Metacentric : Centromere divides the chromosomes into two equal arms with the centromere in the middle.
Functions of nuclear pores :
1. The materials are exchanged between cytoplasm and nucleus through nuclear pores.
2. The proteins are passed in and out of the nucleus through nuclear pores.
3. The enzymes for synthesis of DNA and RNA are passed into nucleus through nuclear pores.
4. Ribosomal subunits and RNA are passed out from nucleus via nuclear pores.
5. m RNA and t RNA are passed out into cytoplasm via nuclear pores.
Passage of polar molecules : Due to bilayer of nonpolar lipid molecules, the polar molecules cannot pass through biomembranes. They require carrier molecules to facilitate their transportation across membrane. The transport of certain molecules takes place against their concentraion gradient from lower to higher concentration, this process requires energy and is an active transport process. The energy is provided by ATP.
Describe the structure of the following with the help of labelled diagrams
Nucleus - Nucleus is the control unit of the cell. It controls the cellular activities of the cell.
Structure - It is spherical in shape. It is composed of the following structures:
Nuclear membrane: It is a double membrane separating the contents of the nucleus from the cytoplasm. The narrow space between the two membranes is called the perinuclear space. Nuclear membrane has tiny holes called nuclear pores. These holes allow specific substances to be transferred into a cell and out from it.
Nucleoplasm/Nuclear matrix: It is a homogenous granular fluid present inside the nucleus. It contains the nucleolus and chromatin. Nucleolus is a spherical structure that is not bound by any membrane. It is rich in protein and RNA molecules and is the site for the formation of ribosomes. Chromatin is an entangled mass of thread-like structures. It contains DNA and some basic proteins called histones.
Centrosome consists of two cylindrical structures called centrioles. Centrioles lie perpendicular to each other. They are surrounded by amorphous pericentriolar materials. Each has a cartwheel-like organisation.
A centriole is made up nine evenly spaced peripheral fibres of tubulin protein. The adjacent triplets are linked together. There is a proteinaceous hub in the central part of a centriole. The hub is connected to the triplets via radial spokes. These centrioles help in organising the spindle fibres and astral rays during cell division. They form the basal body of cilia and flagella.
Mitochondria and choloroplast are :
I. semi-autonomous organelles.
II. formed by division of pre-existing organelles and they contain DNA but lack protein synthesizing machinery.
II is true but I is false
I is true but II is false
Both I and II are false
Both I and II are correct
B.
I is true but II is false
Mitochondria and chloroplast have DNA and are capable of self-replication, thus they are semi-autonomous bodies
The organelles do synthesize some of protein and hence they have the protein synthesizing machinery. However, most of the proteins are derived from the nucleus.
Which one of the following cell organelles is enclosed by a single membrane?
Chloroplasts
Lysosomes
Nuclei
Mitochondria
B.
Lysosomes
All others except lysosomes have double membrane.
One of the major components of cell wall of most fungi is
peptidoglycan
cellulose
hemicellulose
chitin
D.
chitin
Fungi cell wall is made of chitin.
A complex of ribosomes attached to a single strand of RNA is known as
Polymer
Polypeptide
Okazaki's fragment
Polysome
D.
Polysome
A chain of ribosomes attaches to a single mRNA is called polysome or polyribosomes.
Water-soluble pigments found in plant cell vacuoles are
chlorophylls
carotenoids
anthocyanins
xanthophylls
C.
anthocyanins
Anthocyanins are water soluble pigments and appear red, purple depending on pH.
In a chloroplast the highest number of protons are found in
lumen of thylakoids
inter membrane space
antennae complex
stroma
A.
lumen of thylakoids
Proton concentration is higher in the lumen of thylakoid due to photolysis of water. H+ pumping and NADP reductase activity which occurs in stroma of the chloroplast.
A phosphoglyceride is always made up of
only a saturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached
only an unsaturated fatty acid esterified to glycerol molecule to which a phosphate group is also attached
a saturated or unsaturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached
a saturated or unsaturated fatty acid esterified to a phosphate group, which is also attached to a glycerol molecule
C.
a saturated or unsaturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached
A fat is formed of two kinds of smaller molecules, i.e., glycerol and fatty acids. In making a fat three fatty acid molecules each join to glycerol by an ester linkage. A fatty acid has a long carbon skeleton, usually 16 or 18 carbon atom in length. It there is no double bonds between carbon atoms composing the chain, then as many hydrogen atoms as possible are bonded to the carbon skeleton.
Pigment-containing memberanous extensions in cyanobacteria are
heterocysts
basal bodies
pneumatophores
chromatophores
D.
chromatophores
Cyanobacteria contain chlorophyll but the chlorophyll is not located in chloroplasts, rather it is found in chromatophores, infolding of the plasma membrane, where photosynthesis is carried out.
Heterocysts are specialised nitrogen -fixing cells formed from a centriole and a short cylindrical array of microtubules.
Pneumatophores are lateral roots that grow upward for varying distance and function as the site of oxygen intake for the submerged primary roots.
A major site for synthesis of lipids is
RER
SER
symplast
nucleoplasm
B.
SER
The Smooth Endoplasmic Reticulum (SER) is the major site for synthesis of lipids. RER is actively involved in protein synthesis and secretion. Nucleoplasm is the site for active ribosomal RNA synthesis. Symplast is the system of interconnected protoplast through, which water movement occurs.
The Golgi complex plays a major role
in trapping the light and transforming it into chemical energy
in digesting proteins and carbohydrates
as energy transferring organelles
in post-translational modification of proteins and glycosidation of lipids
D.
in post-translational modification of proteins and glycosidation of lipids
Golgi complex plays a major role in post-translational modification of proteins and glycosidation of lipids. Chloroplasts contain chlorophyll, which traps light and transform into chemical energy. Lysosomes are involved in digesting protein, fats and carbohydrates. Mitochondria are energy transferring organelles.
Which of the .following structures is not found in a prokaryotic cell?
Nuclear envelope
Ribosome
Mesosome
Plasma membrane
A.
Nuclear envelope
In a prokaryotic cell, nuclear envelope is not found. It means genetic material (DNA) is not enclosed by any envelope and lies in direct contact with the cytoplasm.
Cell wall is absent in
Aspergillus
Funaria
Mycoplasma
Nostoc
C.
Mycoplasma
True or rigid cell wall is absent in mycoplasm, but their cytoplasm is surrounded by a tri-laminar (triple layered), highly elastic cell membrane of about 10nm in thickness.
Which of the following are not membrane bound?
Vacuoles
Ribosomes
Lysosomes
Mesosomes
B.
Ribosomes
Ribosomes are non-membranous particles these are simple aggregations of RNA(rRNA) and proteins.
The structures that help some bacteria to attach to rocks and/or host tissues are
Rhizoids
Fimbriae
mesosomes
holdfast
B.
Fimbriae
Fimbriae are small bristle-like fibres sprouting out of the cell. In some bacteria, they are known to help is attachment to rocks in streams and also to the host tissues.
The solid linear cytoskeletal elements having a diameter of 6 nm and made up of a single type of monomer are known as
microtubules
microfilaments
intermediate filaments
lamins
B.
microfilaments
Microfilaments (actin filament) are the thinnest filaments of the cytoskeleton. They are found in the cytoplasm of the eukaryotic cells.
The constituents the cytoskeleton through which the cells acquire shape their diameter is approximate. (6 nm)
Cellular organelles with membranes are
nuclei, ribosomes and mitochondria
chromosomes, ribosomes and endoplasmic
endoplasmic reticulum, ribosomes and nuclei
Lysosomes, Golgi apparatus and mitochondria
D.
Lysosomes, Golgi apparatus and mitochondria
Membrane bound organelles include lysosomes, endoplasmic reticulum, Golgi apparatus, mitochondria, chloroplasts, vacuoles, nucleus.
Non-membrance bound organelles include ribosomes, centrioles, microtubules.
The motile bacteria are able to move by
fimbriae
flagella
cilia
pill
B.
flagella
In Bacteria the generalised mode of locomotion is flagella. hair A flagellum is a hair like appen dage that rptrudes fro the cell body. Its primary function is locomotion. A bacterial flagella is made up ofprotein flagella. the bacterial flagellum is deriven by rotary engine made up of protein and is powered by flow of protons (hydrogen) across the bocterial cell.
Which one of the following does not differ in E.coli and Chlamydomonas?
Ribosomes
Chromosomal organisation
Cell wall
Cell membrane
D.
Cell membrane
Cell membrane of prokaryotes is structurally similar to that of eukaryotes. So, it does not differ in E.coli and Chlamydomonas.
What is true about ribosomes?
The prokaryotic ribosomes are 80S, where S stands for sedimentation coefficient.
These are composed of ribonucleic acid and proteins
These are found only in eukaryotic cells
These are self-splicing introns of some RNAs
B.
These are composed of ribonucleic acid and proteins
Ribosomes are large, non-membranous, RNA-protein complexes which are necessary for protein synthesis. In prokaryotes, 70 S type of ribosomes are found while 80 s type of ribosomes are found in eukaryotes.
Nuclear membrane is absent
Penicillium
Agaricus
Volvox
Nostoc
D.
Nostoc
Nostoc is a prokaryote. Prokaryotic cells lack membrane bound organelles and well organized nucleus. (i.e., nuclear envelope is absent).
Penicillium, Agaricus and Volvox are eukaryotic.
Select the correct statement from the following regarding cell membrane.
Na+ and K+ ions move across cell membrane by passive transport
Proteins make up 60 to 70% of the cell membrane
Lipids are arranged in a bilayer with polar heads towards the inner part
Fluid mosaic model of cell membrane was proposed by Singer and Nicolson
D.
Fluid mosaic model of cell membrane was proposed by Singer and Nicolson
In 1972, Singer and Nicolson proposed fluid mosaic model for internal structure of plasma membrane. This is most widely accepted model for plasma membrane. According to this model, a membrane consists of a continuous bilayer of phospholipid molecules in which globular proteins are embedded. The lipids are arranged in a bilayer with polar heads towards outerside.
Which one of the following structures is an organelle within an organelle?
Ribosome
Peroxisome
ER
Mesosome
A.
Ribosome
Ribosomes are smallest known electron microscopic ribonucleoprotein particles attached either to endoplasmic reticulum, floating free in cytoplasm and also found in mitochondria and chloroplast (these are called organeller ribosomes). These are site of protein synthesis.
Which one of the following cellular parts is correctly described?
Thylakoids - flattened membranous sacs forming the grana of chloroplasts
Centrioles - sites for active RNA synthesis
Ribosomes - those on chloroplasts are larger (80s) while those in the cytoplasm are smaller (70s)
Lysosomes - optimally active at a pH of about 8.5
A.
Thylakoids - flattened membranous sacs forming the grana of chloroplasts
Centrioles are a membranous hollow microcylinders occur in pair and play important role in cell division.
Ribosomes in chloroplast are 70 s type while those of cytoplasm in eukaryotic cells are 80 S type. The enzymes of lysosome (called suicidal bag) function at acidic pH (i.e., 5).
The structures that are formed by stacking of organized flattened membranous sacs in the chloroplasts are
cristate
grana
stroma lamellae
stroma
B.
grana
The structures that are formed by stacking of organised flattened membranous sacs (thylakoids) in the chloroplasts are grana. Chloroplasts are organelles found in plant cells that conduct photosynthesis. It is made up of three layers (membranes).
(i) Smooth outer membrane
(ii) Smooth inner (middle) membrane
(iii) Innermost membrane
It has thylakoid system, which is surrounded by the stroma and grana.
Stroma is a alkaline, aqueous fluid which is protein rich.
Grana is formed by stacking of organised flattened membranous sacs called thylakoid.
The chromosomes in which centromere is situated close to one end are
metacentric
acrocentric
telocentric
sub-metacentric
B.
acrocentric
Acrocentric chromosome has centrosome, which is situated almost closed to an end.
There are 4 types of chromosomes according to location of centromere on chromosome (chromatid arms) as
1. Metacentric X-shaped chromosomes with centromere exactly at the middle of two arms
Chromosomes 1 and 3 are metacentric.
2. Acrocentric When one arm is short and centromere is inner to telomere. It is hard to observe short arm but still it is present.
Chromosome 13, 14, 15, 21 and 22 are acrocentric.
3. Submetacentric: Centromere is sub median, so Arm's length are unequal but observable. Chromosomes 4 and 12 are submetacentric.
4. Telocentric: When centromere is located at the terminal end of the chromatid arm.
Human do not possess telocentric chromosome.
Select the correct matching in the following pairs
Smooth ER — Oxidation of phospholipids
Smooth ER — Synthesis of lipids
Rough ER — Synthesis of glycogen
Rough ER — Oxidation of fatty acids
C.
Rough ER — Synthesis of glycogen
Smooth ER-synthesis of lipids is correct match.
Endoplasmic Reticulum (ER) is a network of tubules and flattened sacs in the cell. It is responsible of manufacturing and packaging system. There are two regions of ER as
(i) Rough Endoplasmic Reticulum (RER) It contains ribosomes on its membrane so it synthesis only proteins and also transfer them wherever these are required.
(ii) Smooth Endoplasmic Reticulum (SER) It is smooth because of lack of ribosomes around its membrane. It is involved in the synthesis and storage of lipids, fats, sterols and glycogen etc. 
True nucleus is absent in
Anabaena
Mucor
Vaucheria
Volvox
A.
Anabaena
Anabaena is prokaryotic blue-green alga showing no true nucleus and membrane bound organelles. Rather a nucleoid region containing genetic material is present in the cytoplasm. The other cells of Mucor, Vaucheria and Volvox belongs to eukaryotic fungi and algae.
An organised nucleus or true nucleus present in all eukaryotic cells. It is differentiated into nuclear envelope, chromatin, one or more nucleoli and nucleoplasm. These cell contains membrane-bound organelles e.g. mitochondria, Golgi complex.
Which one of the following is not an inclusion body found in prokaryotes?
Phosphate granule
Cyanophycean granule
Glycogen granule
Polysome
D.
Polysome
Polysome is not an inclusion body found in prokaryotes. Polysomes (polyribosomes or ergosomes) are cluster of ribosomes bound to mRNA molecule are helpful in translation.
Inclusions are dense aggregates of specific chemical compounds in the cell. In prokaryotic cells, phosphate granules accumulates in granules containing long chains of phosphate, which possibly reserve high energy in form of phosphate. Glycogen granules accumulate reserve carbon and energy source and cyanophycean granule is reserve of nitrogen.
Transmission tissue is characteristic feature of
hollow style
solid style
dry stigma
wet stigma
B.
solid style
Transmitting tissue is characteristic feature of solid style. In solid style, there is central region of transmitting tissue, which consists of densely cytoplasmic cells with intercellular mucilage through which pollen tube grow.
DNA is not present in
chloroplast
ribosomes
nucleus
mitochondria
D.
mitochondria
Ribosomes don't contain DNA. It is the site of production of proteins. It also have mRNA, rRNA and tRNA and also other enzymes, which play significant role in protein syntheis. It consists of
60% - 65% - RNA
30% - 35% - Proteins
Whereas, DNA is present in its store house, i.e., nucleus and some DNA is also present in mitochondria and chloroplast.
Nuclear envelope is derivative of
smooth endoplasmic reticulum
membrane of Golgi complex
microtubules
rough endoplasmic reticulum
D.
rough endoplasmic reticulum
Nuclear envelope is a derivative of rough endoplasmic reticulum. It is formed during telophase by fusion of vesicles into which the nuclear envelope develops, during prophase. The perinuclear space present between two membranes of nuclear envelope runs continuous with channels of the ER aiding in shrinkage or expansion of envelope.
Important site for formation of glycoproteins and glycolipids is
Golgi apparatus
plastid
lysosome
vacuole
A.
Golgi apparatus
The Golgi apparatus principally performs the function of packaging materials. Golgi apparatus is the main site of formation of glycoproteins and glycolipids.
In mitochondria, protons accumulate in the
outer membrane
inner membrane
intermembrane space
matrix
C.
intermembrane space
During the passage of two electrons from one an electron carrier (NADH) to another on ETC, enough energy is liberated that pumps out three pairs of protons (H+) from the matrix (inner chamber) to the outer chamber (intermembrane space) of mitochondria.The accumulation of protons in intermembrane space results in their higher concentration than in the matrix creating a proton gradient (ΔpH) and electric potential across the membrane.
Which one of the following is not considered as a part of the endomembrane system?
Golgi complex
Peroxisome
Vacuole
Lysosome
B.
Peroxisome
Cell organelles, whose functions are coordinated, are considered together as an endomembrane system. The endomembrane system includes endoplasmic reticulum (ER), Golgi complex, lysosomes and vacuoles. Since the functions of the mitochondria, chloroplast and peroxisomes are not coordinated with the above components, these are not considered as part of the endomembrane system.
The figure below shows the structure of a mitochondrion with its four parts labelled (A), (B), (C) and (D). Select the part correctly matched with its function
D - outer membrane -gives - rise to inner membrane by splitting
B - Inner membrane - forms infolding called cristae
C - Cristae - possess single circular DNA molecule and ribosomes
A - Matrix - major site for respiratory chain enzymes
B.
B - Inner membrane - forms infolding called cristae
The inner membrane of mitochondria forms a number of infoldings called the cristae (sing- crista) towards the matrix. The Cristae increase the surface area.
Single -celled eukaryotes are included in
Protista
Fungi
Archaea
Monera
A.
Protista
Kingdom - Protista includes all unicellular eukaryotic organisms like flagellates, diatoms, dinoflagellate, slime mould, Sarcodina, etc.
Fungi represent a group of eukaryotic achlorophyllous, non - photosynthetic heterotrophic organisms of diverse forms, sizes, physiology and mode of reproduction. The members of Archaea (Archaebacteria) are prokaryotes and include the extreme halophiles, the thermoacidophiles and the methanogens.
Monera is the kingdome, that in older classifications contain all prokaryotes.
Membrane -bound organelles are absent in
Saccharomyces
Streptococcus
Chlamydomonas
Plasmodium
B.
Streptococcus
Streptococcus is a spherical, gram positive bacterium, Membrane bound organelles are absent in prokaryotes.
Fungi (e.g, Saccharomyces) represents a group of eukaryotic, non-photosynthetic heterotropic organisms. Algae(e.g.Chlamydomonas) is a group of chlorophyll bearing, autotrophic, thalloid plants.
Plasmodium is a genus of protists. Infection by these organsims is know as malaria.
Which one of the following has its own DNA?
Mitochondria
Dictyosome
Lysosome
Peroxisome
A.
Mitochondria
In mitchondria, the inner membrane space is filled with a matrix which contains dense granules along with ribosomes and mitchondrial DNA.The mitochondrial DNA is circular in nature. There number varies from 2-6.Besides DNA, a mitochondrion has RNA and its ribosomes also. Thus, a complete protein synthesizing machinery is present in mitcochondria, which suggeststhe semi -autonomuous nature of mitochondria Dictyosome, lysosome and peroxisome do not have their own DNA.
Select the correct statements out of the four (1-4) given below about lac operon.
Glucose or galactose may bind with the repressor and inactivate it
In the absence of lactose, the repressor binds with the operator region
The z- gene codes for permease
This was elucidated by Francois Jacob and Jacques Monod
C.
The z- gene codes for permease
In prokaryotes, a hypothesis was given in 1961 to explain the protein synthesis regulation. This hypothesis was given by F Jacob and J Monod and for this awarded Nobel Prize in 1965, the hypothesis was known by the name of operon Model.
The main arean of various types of activities of a cell is
Plasma membrane
mitochondrion
cytoplasm
nucleus
C.
cytoplasm
The main area of various types of activities of a cell is cytoplasm. Cytoplasm is an aqueous substance containing a variety of cell organelle along with non- living inclusions. The soluble part of cytoplasm forms the background material or ground substance between the cell organelles.
The plasma membrane consist mainly of
phospholipids embedded in a protein bilayer
Proteins embedded in a phospholipid bilayer
proteins embedded in a polymer of glucose molecules
proteins embedded in a carbohydrate bilayer
B.
Proteins embedded in a phospholipid bilayer
According to fluid mosaic model given by Singer and Nicholson (1972), Plasma membrane consists of a continuous bilayer of phospholipid molecules, in which globular proteins are embedded. This arrangement corresponds to icebergs (proteins) floating in a sea of phospholipids. Proteins stay in the membrane because they have regions of hydrophobic amino acids which interact with fatty acid tails to exclude water. Rest of the molecules is hydrophilic, which faces into or outward, both of which are the aqueous environment.
If for some reason the parietal cells of the gut epithelium become partially non-functional, what is likely to happen?
The pancreatic enzymes and specially the trypsin and lipase will not work efficiently
The pH of stomach will fall abruptly
Steapsin will be more effective
Proteins will not be adequately hydrolyzed by pepsin into proteoses and peptones
D.
Proteins will not be adequately hydrolyzed by pepsin into proteoses and peptones
The parietal cells or oxyntic cells are large, rounded cells located upon the surface of gastric glands. These cells secrete HCl (which converts inactive pepsinogen into active pepsin) and Castle's Intrinsic Factor of CIF (which helps in the absorption of vitamin -B12 or cyanocobalamine). If somehow, parietal cells become partially non-functional, the patient will suffer from achlorhydria (no HCl) or hypochlorhydria (less HCl).This will result in the non- activation of pepsinogen due to which proteins will not be adequately hydrolysed into proteoses and peptones. Lack of CIF will cause vitamin-B12 deficiency, which will result in pernicious anaemia.
An elaborate network of filamentous proteinaceous structures present in the cytoplasm which helps in the maintenance of cell shape is called
thylakoid
endoplasmic reticulum
plasmalemma
cytoskeleton
D.
cytoskeleton
The cytoplasm of all eukaryotic cells is crisscrossed by a network of protein fibres that support the shape of the cell and anchor organelles to fixed locations. This network is called cytoskeleton. It consists of three types of cytoskeletal filaments namely act filaments or microfilaments (formed of globular protein actin), microtubules (formed of tubulin protein) and intermediate filaments (formed of a variety of proteins like vimentin, keratin, desmin, peripherin, lamin etc).
Identify the components labelled A, B, C and D in the diagram below from the list 1 to 8 given along with
1) Cristae of mitochondria
2) Inner membrane of mitochondria
3) Cytoplasm
4) Smooth endoplasmic reticulum
5) Rough endoplasmic reticulum
6) Mitochondrial matrix
7) cell vacuole
8) Nucleus
|
A |
B |
C |
D |
|
5 |
4 |
8 |
3 |
|
A |
B |
C |
D |
|
1 |
4 |
8 |
6 |
|
A |
B |
C |
D |
|
6 |
5 |
4 |
7 |
|
A |
B |
C |
D |
|
5 |
1 |
3 |
2 |
A.
|
A |
B |
C |
D |
|
5 |
4 |
8 |
3 |
A - Rough endoplasmic reticulum
B- Smooth endoplasmic reticulum
C- Nucleus
D -Cytoplasm
Middle lamella is mainly composed of
hemicellulose
muramic acid
calcium pectate
phosphoglycerides
C.
calcium pectate
The middle lamella is cementing layer between the cells. It is made up of Ca and Mg pectates. The basic chemical unit of pectin is galacturonic acid, which has the capability of salt formation with calcium and magnesium (an acid-base reaction).
Plasmodesmata are
lignified cemented layers between cells
locomotory structures
membranes connecting the nucleus with the plasmalemma
connections between adjacent cells.
D.
connections between adjacent cells.
The primary cell wall contains many small openings or pores situated in primary pit fields. The cytoplasm of adjacent cells communicates through the pores by means of cytoplasmic bridges called plasmodesmata. The plasmodesmata permit circulation of fluid and passage of solutes between cells.
Cytoskeleton is made up of
calcium carbonate granules
callose deposits
cellulosic microfibrils
proteinaceous filaments
D.
proteinaceous filaments
The cytoplasm of all eukaryotic cells is crisscrossed by a network of protein fibres that support the shape of the cell and anchor organelles to fixed locations. It is a dynamic system with three types of fibres-actin filaments, microtubule and intermediate filaments.
Given below is a schematic break-up of the phase/stages of cell cycle
Which one of the following is the correct indication of the stage/phase in the cell cycle?
B -Metaphase
C-karyokinesis
D-Synthetic phase
A-Cytokinesis
C.
D-Synthetic phase
Cell cycle completes in two steps- Interphase and M-phase. Interphase is completed in three successive stages G1-phase (post mitotic phase), S-phase (synthetic phase) and G2-phase (pre-mitotic or post-synthetic phase). In the given figure, D is representing the S-phase (synthetic phase) of cell cycle.
Vacuole in a plant cell
is membrane-bound and contains storage
is membrane-bound and contains water and excretory substances
lacks membrane and contains air
lacks membrane and contains water and excretory substances
B.
is membrane-bound and contains water and excretory substances
The cytoplasm of many plants and some animal cells contains numerous small or large sized, hollow, liquid-filled structures, the vacuoles. The vacuoles of plant cells are bounded by a single semipermeable membrane known as tonoplast. These vacuoles contain water, phenol, flavonols, anthocyanins, alkaloids and storage products such as sugars and proteins.
The vacuoles of animal cells are bounded by a lipo proteinaceous membrane and their function is storage, transmission of materials and maintenance of internal pressure of cell.
The length of DNA molecule greatly exceeds the dimensions of the nucleus in eukaryotic cells. How is this DNA accommodated?
Deletion of non-essential genes
Super-coiling in nucelosomes
DNAse digestion
Through elimination of repetitive DNA
B.
Super-coiling in nucelosomes
In eukaryotic cells, DNA accommodated by super-coiling in nucelosomes.
Which one of the following is not a constituent of cell membrane?
Cholesterol
Glycolipids
Proline
Phospholipids
C.
Proline
The lipids of cell membrane are of three types namely phospholipids, glycolipids and sterols. The sterol found in the membrane may be cholesterol (animals), phytosterol (plants) or ergosterol (microorganisms). Cell membrane is made up of lipid + protein (60%) and carbohydrates (2% - 10%). Proline is an amino acid.
During the transmission of nerve impulse through a nerve fibre, the potential on the inner side of the plasma membrane has which type of electric change?
First negative, then positive and again back to negative.
First positive, then negative and continue to be negative
First negative, then positive and continue to be positive
First positive, then negative and again back to positive
A.
First negative, then positive and again back to negative.
During the transmission of nerve impulse through a nerve fibre, the potential on the inner side of the plasma membrane has first negative charge, then positive and again negative by repolarization.
Select the wrong statement from the following:
Both chloroplasts and mitochondria contain an inner and an outer membrane
Both chloroplasts and mitochondria have an internal compartment, the thylakoid space bounded by teh thylakoid membrane
Both chloroplasts and mitochondria contain DNA
The chloroplasts are generally much large than mitochondria
B.
Both chloroplasts and mitochondria have an internal compartment, the thylakoid space bounded by teh thylakoid membrane
Thylakoid space is present only in chloroplasts. The inner membrane of mitochondria folded to form crystae.
If you are asked to classify the various algae into distinct groups, which of the following characters you should choose?
types of pigments present in the cell
nature of stored food materials in the cell
structural organization of thallus
chemical comppsition of the cell wall
A.
types of pigments present in the cell
Type of pigments present in the cell of algae is the most important character for classification.
A major breakthrough in the studies of cells came with the development of electron microscope. This is because
the resolution power of the electron microscope is much higher than that of the light microscope
the resolving power of the electron microscope is 200 – 350 nm as compared to 0.1 – 0.2 nm for the light microscope
electron beam can pass through thick materials, whereas light microscopy requires thin sections
the electron microscope is more powerful than the light microscope as it uses a beam of electrons which has wavelength much longer than that of photons
A.
the resolution power of the electron microscope is much higher than that of the light microscope
A major break through in the studies of cell came with the development of electron microscope because the resolution power of the electron microscope is much higher than that of the light microscope.
As an average the resolving power of a light microscope is 
while of electron microscope, is 
though theoretically, it is 
. The magnification range of light microscope is 2000 - 4000 while of electron microscope is 1,00,000 - 3,00,000.
Which of the following statements regarding cilia is not correct?
The organized beating of cilia is controlled by fluxes of Ca2+ across the membrane
Cilia are hair-like cellular appendages
Microtubules of cilia are composed of tubulin
Cilia contain an outer ring of nine doublet microtubules surrounding two single microtubules
C.
Microtubules of cilia are composed of tubulin
Cilia are minute, harilike processes on the surface of protozoans or of metazoans cells ehich by their motion accomplish locomotion or produce a current. Each cilium contains a peripheral circle of nine doublet microtubules arranged around two single microtubules. Each microtubule is composed of tubulin proteins.
Although the mechanism of ciliary movement is not completely under stood. It is known that the microtubules behave as sliding filament that move past one another much like the sliding filaments of vertebrate skeletal muscle.
The fluxes of Ca2+ across the membrance is not responsible for controlling the organized beating or cilia.
Cri-du-chat syndrome in humans is caused by the
fertilization of an XX egg by a normal Y-bearing sperm
loss of half of the short arm of chromosome 5
loss of half of the long arm of chromosome 5
trisomy of 21st
B.
loss of half of the short arm of chromosome 5
Cri du chatchat (cat cry) syndrome in human is caused by the deletion of short arm of chromosome 5. The effective new born cries like mewing of cat .Which of the following RNAs should be most abundant in animal cell?
r-RNA
t-RNA
m-RNA
mi-RNA
A.
r-RNA
rRNA is most abundant in animal cell. It constitutes 80% of total RNA of the cell
Which of the following components provides sticky character to the bacterial cell?
Cell wall
Nuclear membrane
Plasma membrane
Glycocalyx
D.
Glycocalyx
Sticky character of the bacterial wall is due to glycocalyx or slime layer. This layer is rich in glycoproteins
Statement I Microtubules are formed only in animal cells.
Statement II Microtubules are made up of a protein called myosin.
Choose the correct option
Statement I is correct and statement II is incorrect.
Statement II is correct and statement I is incorrect.
Both statement are correct
Both statements are incorrect
D.
Both statements are incorrect
Microtubules are found in both animal and plant cells and are formed of the protein tubulin.
The chromosome in which centromere is situated close to one end are
Metacentric
Acrocentric
Telocentric
Sub-metacentric
B.
Acrocentric
In the acrocentric chromosome, the centromere is situated close to one end of the chromosome.
Animal cell differ from plant cell in possessing
Vacuoles
Centrosomes
Pastids
Mitochondria
B.
Centrosomes
The centrosome is a self-propagating cytoplasmic organelle located near the nucleus of an animal cell.
Which of the following organelles does not contain RNA?
Plasmalemma
Ribosome
Chromosome
Nucleolus
A.
Plasmalemma
The plasmalemma series as the interface between the machinery in the interior of the cell and the Extracellular Fluid. (ECF) that bathes all cells. It is devoid of the ribosome.
Dutrochet has given the concept about cell in
1834
1814
1822
1824
D.
1824
In 1824, Pene Dutrochet, a French scientist wrote that all animal and plant tissues were aggregate of globular cells.
Which of the following is an epidermal cell containing chloroplast?
Stomata
Hydathode
Guard cell
None of these
C.
Guard cell
Guard cell is the specialised epidermis cells containing chloroplast.
Match the following entities of column I with their respective orders of column II and choose the correct combination form the option.
| Column I | Column II |
| A. Wheat | 1. Primate |
| B. Mango | 2. Diptera |
| C. Housefly | 3. Sapindales |
| D. Man | 4. Poales |
| A | B | C | D |
| 4 | 3 | 2 | 1 |
| A | B | C | D |
| 1 | 2 | 4 | 3 |
| A | B | C | D |
| 3 | 4 | 2 | 1 |
| A | B | C | D |
| 2 | 4 | 1 | 3 |
A.
| A | B | C | D |
| 4 | 3 | 2 | 1 |
Meiosis is best observed in dividing
Cell of lateral meristem
Cells of apical meristem
Microsporocytes
Microspores and anther wall
C.
Microsporocytes
Meiosis is best observed in dividing microsporocytes. Microsporocytes or microspore mother cell after meiosis gives rise to microspore.
In mitochondria, enzyme cytochrome oxidase is present in
Outer membrane
Perimitochondrial space
Inner Membrane
Matrix
C.
Inner Membrane
Mitochondria contains various enzymes as follows:
(i) Outer membrane Acetyltransferase, glycerophosphatase, phospholipase-A,monoamine oxidase, etc.
(ii) Inner membrane Cytochrome oxidase,dehydrogenase, succinate NADH, dehydrogenase, ATPase, etc.
(iii) Perimitochondrial space Adenylate kinase, nucleoside diphosphokinase, etc.
(iv) Matrix Pyruvate dehydrogenase, citrate synthase, aconitase, isocitrate dehydrogenase, fumarase, c-ketoglutarate dehydrogenase, malate dehydrogenase, etc.
Which of the following tissues consist of living cells?
Vessels
Tracheids
Companion cell
Sclerenchyma
C.
Companion cell
Companion cells are present between sieve tubes in the phloem of angiosperms. These are the living cells with large nucleus that controls the activity of non-nucleated sieve tubes.
Which of the following plant cells is not surrounded by a cell wall?
Root hair cell
Stem hair cell
Gamete cell
Bacterial cell
C.
Gamete cell
The gamete is the haploid reproductive cell that fuses with another gamete to form a diploid zygote. These are not surrounded by the cell wall. On the other hand, root hair cell, stem hair cell and bacterial cell, all possess a well-defined cell wall.
Which of the following cell organelles stores hydrolytic enzymes?
Centriole
Lysosome
Chromoplast
Chloroplast
B.
Lysosome
Lysosomes are the single membrane-bound cell organelles, which contain hydrolytic enzymes. These are also known as suicidal bags.
The powerhouse of cells is first discovered by
C Benda in 1897
Kolliker in 1850
Claude in 1880
Kingsburg in 1882
B.
Kolliker in 1850
Mitochondria which is also known as the power house of the cell was first discovered by Kolliker in 1850. It is the site of cellular respiration.
During chloride shift or Hamburger phenomenon, when the whole blood is saturated with CO2, following changes occurs. Which one of them is not correct?
Bicarbonate content of plasma and corpuscles increase
Chloride content of plasma diminished and that of the cell is increased
Total base of blood remain unchanged
Water content and volume of corpuscles decrease
D.
Water content and volume of corpuscles decrease
According to Hamburger phenomenon, when the whole blood is saturated with carbon dioxide, the following changes are seen
(i) The bicarbonate contents of plasma and corpuscles increase.
(ii) The chloride content of plasma lo diminished and that of the cell is increased.
(iii) The total base (cations) of both plasma and corpuscles remain unchanged.
(iv) The water content and the volume of corpuscles increase.
(V) When the carbon dioxide is removed from the blood reverse changes takes place.
(vi) When CO2, enters the blood, Cl- from plasma enters RBCs leaving Na+ behind. When CO2 escapes from blood Cl- leaves the cell and combines with Na+ again. Due to this alternate movement of Cl ions, this phenomenon is called chloride shift.
The Sub-units of 80S ribosome will be
40S, 40S
60S, 40S
60S, 20S
55S, 25S
B.
60S, 40S
60S and 40S are sub-units of eukaryotic (80S) ribosomes.
Match the following column I and II for organismic respiration.
| Column I | Column II |
| A. Respiration in bacteria | 1. Mitochondria |
| B. Respiration in cyanobacteria | 2. Cytoplasmic membrane |
| C. Respiration in eukaryotic cell | 3. Mesosomes |
A-2, B-3, C-1
A-3, B-2, C-1
A-1, B-3, C-2
A-3, B-1, C-2
B.
A-3, B-2, C-1
Respiration is carried out by different types of organisms at different sites. In bacteria and cyanobacteria, the mitochondria are not present, so respiration occurs in them in mesosomes.
Ribosomes are particles about 200 Å units in diameter consisting of protein and RNA. The percentage of protein and RNA is respectively
80% and 20%
60% and 40%
50% and 50%
40% and 60%
B.
60% and 40%
Chemically, ribosomes are made up of rRNA 60% and protein 40%. These are known as protein factories as these are the sites for protein synthesis.
Which of the following sequences represent a possible pathway in the production of a secretory protein?
Rough ER → Secretory vesicle → Ribosome → Golgi apparatus
Ribosome → Rough ER → Golgi apparatus → Secretory vesicle
Secretory vesicle → Golgi apparatus → Ribosomes → Rough ER
Rough ER → Ribosomes → Secretory vesicles → Golgi appratus
D.
Rough ER → Ribosomes → Secretory vesicles → Golgi appratus
Ribosome is the place where protein synthesis takes place →rough ER produces proteins and helps them fold property → Golgi bodies does packaging of proteins → secretory vesicles does the transport of proteins.
The phrase 'Omnis cellula e cellula' was given by
Virchow
Pasteur
Schleiden
Brown
A.
Virchow
In 1855 Rudolf Virchow extended the cell theory and stated that all cells arise from pre-existing cells, i.e., Omnis cellula e cellula.
Membrane is absent in
Nucleus
Nucleolus
Vacuole
Lysosome
B.
Nucleolus
Nucleolus is a darkly stained granular, naked organelle with no limiting membrane. It is formed of proteinaceous part pars amorpha, fibrillar zone and granular zone of ribonucleoprotein and granules.
In prokaryotes, chromatophores are
Specialised granules responsible for the colouration of cells
Structures responsible for organising the shape of the organism
Inclusion bodies lying free inside the cells for carrying out various metabolic activities
Internal membrane systems that may become extensive and complex in photosynthetic bacteria
D.
Internal membrane systems that may become extensive and complex in photosynthetic bacteria
In some prokaryotes like, photosynthetic bacteria and blue-green algae possess small membrane lined chromatophores, which is similar to but chemically simpler than the chlorophyll of plants.
Endoplasmic reticulum is in continuation with
Golgi body
nuclear wall
mitochondria
cell wall
B.
nuclear wall
Endoplasmic reticulum is the network of delicate strands and vesicles that extends from cell membrane to nuclear membrane.
Cell wall is the outermost covering of plant cell made up of cellulose.
Golgi bodies are double membrane bound cell organelles of eukaryotic cells which consist of vesicle, tubule and cisternae.
Mitochondria is a rod shaped, double membrane bound cell organelles.
The vacuole is lined by a membrane called
tonoplast
jacket
cell membrane
tonoplasm
A.
tonoplast
The vacuole is lined by a membrane called tonoplast.
Jacket layer is present around archegonia and antheredia in bryophytes.
Tonoplasm is the content or liquid present inside the vacuole enclosed by a tonoplast membrane.
Cell membrane is the semi- permeable membrane enclosing the protoplasmic material of a cell.
Cell theory was proposed by
Virchow
Schleiden and Schwann
Robert Hooke
B McClintock
B.
Schleiden and Schwann
In 1838- 1839, Matthias Schleiden and Theodore Schwann, together formulated cell theory.
Who for the first time developed electron microscope?
Knoll and Ruska
Rudolf and Kolliker
Robert Hooke
Swanson
A.
Knoll and Ruska
Knoll and Ruska discovered electron microscope in 1932.
During DNA replication in prokaryotes DNA is anchored to
chromosome
mesosome
nucleolus
ribosome
B.
mesosome
Mesosomes are the circular coiled bodies present on the plasma membrane of bacteria. These are prominent in Gram +ve bacteria. These also receive DNA during conjugation and DNA replication enzyme.
The mineral present in cell wall is
Na
Ca
K
Mg
B.
Ca
The main components of cell wall are:-
1. Matrix- It consists of water (60%), hemicellulose (5-15%), pectic substances (2-8%), lipids (0.5- 3.0%) and proteins (1-2%).
2. Microfibrils- Cellulose or fungus cellulose (10-15%).
3. Other ingredients- Lignin, cutin, suberin, silica, minerals (Fe, Ca, Carbonate), waxes, tannins etc.
Calcium (Ca2+) ions are used as cations to balance anions in the plant vacuole. It helps in maintaining the chemical balance in the soil that reduces soil salinity and improves water penetration.
Which organelle is present in higher number in secretory cells?
Dictyosome
ER
Lysosome
Vacuole
A.
Dictyosome
Dictysosme or Golgi Complex is present in higher number in secretory cells. All glandular cells depend upon Golgi complex for concentrating and pouring secretion to outside.
Cell membrane in animals is composed mainly of the molecule of
lipids
proteins
lipids and proteins
carbohydrates
C.
lipids and proteins
Major constituents of plasma membranes are Protein(60%) and lipids(40%). The percentage of carbohydrates ranges from 1-10 which are in the form of glycoproteins or glycolipids.
Proteins may be extrinsic(peripheral) and intrinsic(integral) while lipids may be phospholipids, sphingolipids, glycolipids and sterols(eg- cholesterol).
A student wishes to study the cell structure under a light microscope having 10X eyepiece and 45X objective. He should illuminate the object by which one of the following colours of light so as to get the best possible resolution?
Yellow
Green
Blue
Red
C.
Blue
Resolving Power or resolution is the ability of the lens to distinguish fine details and structure. It is the ability of a lens to differentiate between two points at a specified distance apart.
Resolving Power =
It depends upon 2 factors:
(i) Wavelength of light used for illumination
(ii) Power of objective lenses
Among Yellow, green, red and blue light; Blue colour has the shortest wavelength so, it will give best resolution.
Which one is single membrane cell organelle
Endoplasmic reticulam
Mitochondria
Lysosomes
Chloroplast
C.
Lysosomes
Endoplasmic reticulum, mitochondria and chloroplast are double-membraned cells organelle whereas lysosome is a single membrane cell organelle.
Centromere is required for
transcription
crossing over
cytoplasmic cleavage
movement of chromosomes towards poles
D.
movement of chromosomes towards poles
Chromosomes are responsible for the transmission of the hereditary information from one generation to the next. Arms of the chromosome is known as chromatid. They are joined together in the centre known as centromere or primary constriction. During cell division, spindle fibres attach to centromere and help in the movement towards the poles.
Protein synthesis in an animal cell occurs
only on the ribosomes present in cytosol
on ribosomes present in cytoplasm as well as in mitochondria
only on ribosomes attached to the nuclear envelope and endoplasmic reticulum
on ribosomes present in the nucleolus as well as in cytoplasm
B.
on ribosomes present in cytoplasm as well as in mitochondria
Protein synthesis takes place in ribosomes. In an eukaryotic cell, ribosomes are present in cytoplasm, mitochondria and chloroplasts. Therefore, protein synthesis takes place in cytoplasm, mitochondria and chloroplasts.
The main organelle involved in modification and routing of newly synthesized proteins to their destinations is
mitochondria
endoplasmic reticulum
lysosome
chloroplast
B.
endoplasmic reticulum
Endoplasmic Reticulum (ER) was coined by Porter. It is a network of tubules, vesicles and cisternae within an eukaryotic cell. Two types of ER are recognised on the basis of presence or absence of ribosomes on the wall of ER:
(i) Smooth ER- It helps in the synthesis of lipid and glycogen. Wall does not contain ribosomes.
(ii) Rough ER- It helps in protein synthesis and transfer. Wall contains ribosomes.
Protein synthesis takes place in ribosomes attached on wall of ER. Newly formed protein enters within the cavity of rough ER and follows following path:
Protein Cavity of rough ER Cavity of smooth ER Golgi membrane Lysosomes or transport vesicles or secretory granules.
Cell theory was propounded in 1838-39 by
Schleiden
Schwann
Schleiden and Schwann
Virchow
C.
Schleiden and Schwann
The cell theory or cell doctrine is credited to Matthias Schleiden (1838) a botanist of Germany and Theodor Schwann (1839), a zoologist also of Germany
The basic unit of chitin is
N-acetyl glucosamine
glucose
galactose
fructose
A.
N-acetyl glucosamine
The chitin (polyglycosamine) is an acetate of mucopolysaccharide called glycosamine which is formed by the combination of polysaccharide with small peptide molecules. The basic unit (monomer) of chitin is N-acetylglucosamine, monomers are joined by 1-4 linkages.
Arachidonic acid is
non-essential fatty acid
essential fatty acid
poly unsaturated fatty acid
both 'b' and 'c'
D.
both 'b' and 'c'
Arachidonic acid is polyunsaturated (i.e., have more than one double bond) and essential fatty acids. Essential fatty acids cannot be synthesised by the body of animal and has to be taken from outside to fulfil the body requirement. Linoleic acid and linolenic acid are also essential fatty acids.
What type of enzyme are present in lysosome
ATPase
Hydrolytic
Lyase
None of these
B.
Hydrolytic
Lysosomes or suicidal bags are bounded by single unit membrane. It contains hydrolytic enzymes which help to digest the nucleic acids, proteins and polysaccharide etc. (i.e., extracellular material). It also helps in autolysis.
In which part of mitochondria does ATP synthesis occur?
F1
F0
Cristae
Inner membrane of mitochondria
A.
F1
During the oxidation process (occurs in inner mitochondrial membrane during electron transport system), enormous amount of free energy is released, some of which is utilised by inner membrane sub units or F1 particles containing three coupling factors and ATP enzyme, in the synthesis of ATP molecules.
Phospholipids are
amphipathic
hydrophobic
amphibolic
none of these
A.
amphipathic
The phospholipid is a bipolar molecule having long fatty acid called hydrophobic tail (water hating) or non-polar end. Another is hydrophillic (water loving) or polar end, hence, it is amphipathic in nature
In bacteria respiration occurs in
cytoplasmic membrane
mitochondria
nuclear membrane
endoplasmic reticulum
A.
cytoplasmic membrane
In bacteria, respiration occurs in cytoplasmic membrane bacteria is a prokaryotic cell (true nucleus and membrane bounded organelle are absent).
'All tissues consist of cells' sentence was said by
Wallace
Virchow
Schleiden
None of these
C.
Schleiden
Schleiden (1838) proposed cell theory and said, 'all tissues consist of cell'.
Maximum absorption of light occurs in the region of
400 - 700 nm
700 - 900 nm
1000 - 1200 nm
1500 - 2000 nm
A.
400 - 700 nm
Wavelengths shorter than 380 nm have too much energy which can disrupt the molecular organisation of cell; wavelength longer than 750 nm do not have energy to raise an electron to a higher orbital.
Assertion : Pili are tubular structures present in bacteria which help in conjugation.
Reason : Formation of pili is controlled by F+ or fertility factor.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false
If both assertion and reason are false
B.
If both assertion and reason are true but reason is not the correct explanation of assertion.
Pili are long and thick tubular outgrowths, which develop in response to F or fertility factor in Gram negative bacteria. They are made up of protein pilin. A donor bacterial cell having fertility factor develops 1-4 pili. Pili are helpful in attaching to recipient cell and forming conjugation tube.
Assertion : In opposite phyllotaxy two leaves are borne on the opposite sides of a single node.
Reason : Opposite phyllotaxy is seen in China rose and Oleander.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
C.
If assertion is true but reason is false
In opposite phyllotaxy, two leaves are borne on the opposite sides of a single node e.g., Quisqualis (opposite and superposed) and Calotropis (opposite and decussate). Nerium or Oleander shows whorled type of phyllotaxy and China rose exhibits alternate phyllotaxy.
The larvicidial fish used in biocontrol of mosquitoes
Gambusia
Hilsa
Scatophagus
Gold fish
A.
Gambusia
Gambusia is an exotic fish feeds on the larvae of mosquito. Now-a-days it is widely used to eradicate mosquito.
The joint of radio-ulna with the upper arm is
hinge joint
pivot joint
socket joint
none of these
A.
hinge joint
In hinge joint a condyle at the end of one bone fits in the depression of other bone in such a manner that the bone with condyle can swung like a loop on its hinge only in one direction e.g. leg elbow joint, ankle joint and knee joint etc.
The outermost limiting layer of mycoplasma is made up of
cell wall
cell membrane
mucilaginous sheath
slime layer
B.
cell membrane
Mycoplasma are the smallest and simplest free living Gram Negative Prokaryotes or Monerans. In these, cell wall is absent. Plasma Membrane forms the outer boundary of the cell. A substantial amount of polysaccharides having acetyl glucosamine are associated with cell membrane.
Specific proteins responsible for the flow of materials and information into the cell are called
membrane receptors
carrier proteins
integral proteins
none of these
B.
carrier proteins
Active transport is the uphill movement of materials across the membrane where the solute particles move against their concentration gradient or electro- chemical gradient. It takes place through special organic molecules called carrier molecules or carrier particles or carrier proteins. For each solute particle, there is a special carrier molecule. It has its own binding site on the two surfaces of the membrane. Substrate combines with the carrier to form carrier solute complex. It further undergoes a conformational changes and is transported to other side of the membrane. ATP provides energy to the carrier.
Assertion : Nucleus is the controlling centre of a cell.
Reason : Pores in the nuclear envelop regulate the flow of materials in and out of the nucleus.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
B.
If both assertion and reason are true but reason is not the correct explanation of assertion
Nucleus is the controlling centre of a cell as it contains chromosomes and genes. Chromosomes contain the DNA which by transcription prepare RNA which in turn leads to the formation of proteins by translation. These proteins regulate the various metabolic processes going in the cell. Besides this, nucleus contains genetic information for reproduction, development & behaviour of an organism.
Nuclear membrane is double layered, semipermeable and is perforated by minute, circular nuclear pores. The pore controls the passage of macromolecules like tRNAs, mRNAs, ribosomal proteins, enzymes etc. during different processes of transcription, translation etc.
'Omnis-cellula-e-cellula' was given by
Virchow
Hooke
Leeuwenhoek
Brown
A.
Virchow
Rudolf Virchow was the first to suggest that new cells are formed from the division of the pre-existing cells - 'omnis-cellula-e-cellula' i.e. every cell is derived from a previous cell.
Robert Hooke was the first to coin the term 'cell' for small structures in a piece of cork under a microscope. His observations were published in a book named Micrographia.
Leeuwenhoek was the first person to observe and describe microscopic organisms and living cell. He observed nucleus in RBC of salmon fish and used simple lens and observed nuclei and unicellular organisms including bacteria. In 1676, he described the bacteria and gave the term animalcules. His observations laid the foundations for the science of bacteriology and microbiology. Robert Brown ( 1831) described and named nucleus.
Which of the following is responsible for the mechanical support, protein synthesis and enzyme transport?
Cell membrane
Mitochondria
Dictyosome
Endoplasmic reticulum
D.
Endoplasmic reticulum
Endoplasmic reticulum functions as cytoskeleton or intracellular and ultrastructural skeletal framework by providing mechanical support to colloidal cytoplasmic matrix. Proteins and enzymes synthesized by ribosomes enter the channels of rough endoplasmic reticulum both for intracellular use as well as extracellular transport.
In prokaryotes, chromatophores are
specialized granules responsible for colouration of cells
structures responsbile for organizing the shape of the organism
inclusion bodies lying free inside the cells for canying out various metabolic activities
internal membrane systems that may become extensive and complex in photosynthetic bacteria
D.
internal membrane systems that may become extensive and complex in photosynthetic bacteria
Chromatophores are internal membrane systems present in photosynthetic prokaryotes. These develop as membrane lined sacs or thylakoids from plasma membrane. Thylakoid membranes contain photosynthetic pigments in cyanobacteria and purple bacteria. Small sacs or granules containing pigments phycobilin are attached to these membranes. In green bacteria chromatophores are covered by non-unit, non-lipid protein membrane. They are sometimes called chlorosomes.
Many cells function properly and divide mitotically even though they do not have
plasma membrane
cytoskeleton
mitochondria
plastids
D.
plastids
The presence of plastid is a feature of plant cells but animal cells are devoid of them. Even then they function properly and divide mitotically similar to plant cells.
Three of the following statements regarding cell organelles are correct while one is wrong. Which one is wrong?
Lysosomes are double membraned vesicles budded offfrom Golgi apparatus and contain digestive enzymes.
Endoplasmic reticulum consists ofa network of membranous tubules and helps in transport, synthesis and secretion
Leucoplasts are bound by two membranes, lack pigment but contain their own DNA and protein synthesizing machinery
Sphaerosomes are single membrane bound and are associated with synthesis and storage of lipids
A.
Lysosomes are double membraned vesicles budded offfrom Golgi apparatus and contain digestive enzymes.
Lysosomes are roughly spherical bodies bounded by a single membrane. They are manufactured by the Golgi apparatus. Lysosomes are small membrane bound vesicles in the cytoplasm of cells which contain toxic enzymes. When a cell dies, these membranes rupture and the enzymes are released. They break down the cells structure, and the debris is removed.
Assertion: Gram-negative bacteria do not retain the stain when washed with alcohol.
Reason: The outer face of the outer membrane of Gram-negative bacteria contains lipopolysaccharides, a part of which is integrated into the membrane lipids
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
A.
If both assertion and reason are true and reason is the correct explanation of assertion
The technique of staining bacteria was given by a Dutch microbiologist Christian Gram (1884) and this technique is known as Gram staining. In the cell wall of gram +ve bacteria both horizontal and vertical peptide linkages arc present due to which mesh is dense and stain does not come out. Futher outer layer of cell wall of Gram +ve bacteria is made up of teichoic acid. In the cell wall of gram ve bacteria, either horizontal or vertical peptide linkages are present. due to which mesh is loose and hence stain comes out when washed with alcohol. Further outermost layer of cell wall of Gram-ve bacteria is made up lipopolysaccharides.
Assertion : Mitochondria and chloroplasts are semi-autonomous organelles.
Reason : They are formed by division of pre-existing organelles as well as contain DNA but lack protein synthesizing machinery.
If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion
If Assertion is true but Reason is false
If both Assertion and Reason are false
C.
If Assertion is true but Reason is false
Mitochondria and chloroplasts both are double membrane organelles. They are semi autonomous because both their structure and functions are partially controlled by nucleus and partially by themselves. Both the organelles have their own DNA and arise from pre-existing cells. Synthesis of many amino acids occur in mitochondria. Glutamic acid and Aspartic acid were the first amino acids. Plastids also manufacture some of its own proteins, enzymes and other chemicals because of the presence of 70S ribosomes which can help translate the coded information contained in mRNAs transcribed over chloroplast DNA.
Assertion : A cell membrane shows fluid behaviour.
Reason : A membrane is a mosaic or compositeof diverse lipids and proteins.
If both Assertion and Reason are true and the reason is the correct explanation of the assertion
If both Assertion and Reason are true but the reason is not the correct explanation of the assertion
If Assertion is true statement but Reason is false
If both Assertion and Reason are false statements
A.
If both Assertion and Reason are true and the reason is the correct explanation of the assertion
The structure of cell membrane can be described by the fluid-mosaic model. It was given by Singer and Nicolson in 1972. The essential feature of fluid-mosaic model is cell membranes are considered to be quasifluid structures in which the lipids and proteins are in mosaic manner. It is considered to be as the lipid-protein association (mosaic) and also to be hydrophobic. The fluidity of the membrane is the result of this hydrophobic interaction, thus a cell membrane shows fluid behaviour.
A prokaryotic cell lacks :
nucleus
nuclear membrane
membrane bound organelles
all of the above
D.
all of the above
Prokaryotes are unicellular or multicellular organisms. These lack true nucleus, nuclear membrane and membrane bound organelles such as mitochondria, Golgi bodies, lysosomes etc. It also lacks Endoplasmic reticulum or ER.
Extranuclear inheritance is a consequence of the presence of genes in :
ER and mitochondria
lysosomes and ribosomes
ribosomes and chloroplast
mitochondria and chloroplasts
D.
mitochondria and chloroplasts
Mitochondria and chloroplast contain DNA. The extranuclear inheritance or cytoplasmic inheritance is a consequence of the presence of genes in mitochondria and chloroplasts.
Vesicles of Smooth Endoplasmic Reticulum (SER) are most likely on their way to :
plastids
lysosomes
nucleolus
Golgi apparatus
D.
Golgi apparatus
Smooth endoplasmic reticulum or SER forms transport vesicles by which large molecules are moved in the cell. Often transport vesicles are on their way to the plasma membrane or another part of the endomembrane system particularly the Golgi apparatus.
Lysosomes are the store house of :
ATP
sugar
proteins
hydrolytic enzymes
D.
hydrolytic enzymes
Lysosomes may be formed directly from endoplasmic reticulum (ER). Enzymes are stored within the lysosomes as crystalline form mainly as hydrolytic enzymes. These enzymes are synthesized on RER. These enzymes help in the digestion if required.
The genetic material of prokaryotic cell is called :
nucleus
nucleolus
nucleoid
centromere
C.
nucleoid
Prokaryotic cell consists of a small amount of genetic material in the form of a single molecule or chromosome of circular DNA. It lies in the centre of a single chromosome. Hence, it is known nucleoid or genophore.
In prokaryotes, the genetic material is :
linear DNA with histones
circular DNA with histones
linear DNA without histones
circular DNA without histones
D.
circular DNA without histones
In prokaryotes, the genetic material consists of single circular DNA without any associated protein i.e., without histones, lying in a tangled mass (nucleoid).
Mesophyll cells, which liberate malic acid at night time, are of :
C4 - plants
C3 - plants
C2 - plants
C1 - plants
A.
C4 - plants
The plants in which first stable product for the initial CO2 fixation in dark reaction, is malic acid are known as C4 -plants. During night time, carbon dioxide combines with phosphoenol pyruvic acid (PEPA) to form oxaloacetic acid in mesophyll chloroplasts which converts to malic acid.
What is the structural element of cell wall?
Matrix
Microtubules
Microfibrils
Arabinogalactans
C.
Microfibrils
The cell wall contains a porous matrix of cellulose consisting of vary fine coalesced fibrils the microfibrils and an interfibrillar system of microcapillaries containing various non-cellulosic wall constituents.
The Gram (-) bacteria detect and respond to the chemicals in their surroundings by
muramic acid
lipopolysaccharide
volutin granules
porin
D.
porin
In cell wall of Gram-negative bacteria, the peptidoglycan layer is very thin. The outer membrane is a bilayered structure consisting chiefly of phospholipids, proteins and lipo-polysaccharides. The permeability of outer membrane to nutrients is provided by proteins called porins, which form channels in the membrane.
Small particles projecting from the inner membranes and cristae of mitochondria are known as
myeloid bodies
microsomes
informosomes
oxysomes
D.
oxysomes
A number of knob-like, stalked structures arising from the inner surface of inner membrane of mitochondria project into the matrix and these are called elementary particles or F1 particles or oxysomes.
The resolving power of a compound light microscope will be greatest if the source of light is
blue
green
yellow
red
A.
blue
In compound microscope, the visible light of wavelength 3900-7600 Angstrom is used as source of light.The resolving power (ability to distinguish two closely related points) of light microscope is maximum (0.4 µm) in blue light.
Primary and secondary active transport both
generate ATP
use ATP directly
can move solutes against their concentration gradient
include the passive movement of glucose molecule
C.
can move solutes against their concentration gradient
Active transport requires energy, as in this transport molecules move against the concentration gradient, ie, from region of low concentration to region of high concentration primary active transport is directly related with chemical energy or electrical energy, while secondary active transport is related to the chemiosmotic energy.
Which type of membrane is most abundant within a cell?
ER membrane
Nuclear membrane
Golgi membrane
Plasma membrane
A.
ER membrane
Endoplasmic reticulum is membrane bound channel, which is seen in the form of a network of delicate strands and vesicles in the cytoplasm. ER membrane is most abundant within a cell.
In which method of transport, in plasma membrane does not require carrier molecule?
Active transport
Facilitated diffusion
Simple diffusion
Na+ - K+ pump
C.
Simple diffusion
In simple diffusion transport across the cell membrane takes place unaided, ie, molecule of gases such as oxygen, carbon dioxide and small molecules enter the cell by crossing the membrane without the help of any permease.
Which structure is present in both prokaryotic and eukaryotic plant cells?
Cell wall
Nucleus
Chloroplast
Mitochondria
A.
Cell wall
Cell wall is present in both prokaryotic (bacteria) and eukaryotic plant cell. Nucleus, mitochondria and chloroplast are absent in prokaryotic cell.
What is telomere? State its function.
Telomere is the end of chromosome, which consists of tandemly repeated short sequences of DNA. Each time a cell divides some sequences of the telomere are lost, eventually (after 60-100 divisions in an average cell) the cell dies. Replication of telomeres is directed by telomerase, an enzyme consisting of RNA and protein that is inactive in normal cells of higher organisms.
What is riophorins?
Ribophorins are ribosome receptor proteins that aids in the binding of ribosomes to the rough endoplasmic reticulum. It is an integral protein within the rough endoplasmic reticular membrane. As it is directly related with protein translation, ribophorins are not found in smooth endoplasmic reticulum.
What is mitoplast?
Membraneless mitochondria
Another name of mitochondria
Mitochondria without outer membrane
Mitochondria without inner membrane
C.
Mitochondria without outer membrane
Mitoplast is a mitochondrion without the outer membrane.
Thylakoids occur inside
mitochondria
chloroplast
Golgi apparatus
endoplasmic reticulum
B.
chloroplast
A thylakoid is a membrane bound compartment inside the chloroplasts and cyanobacteria. They are the site. of the light dependent reactions of photosynthesis.
Mitochondria are semiautonomous as they possess
DNA
DNA and RNA
DNA, RNA and ribosomes
Protein
C.
DNA, RNA and ribosomes
Each mitochondrion is a double membrane bound structure with the outer membrane and the inner membrane dividing its lumen distinctly into two aqueous compartments, ie, the outer compartment and the inner compartment. The inner compartment is called the matrix. The matrix possesses single circular DNA molecule, a few RNA molecules, ribosomes (70S) and the components required for the synthesis of proteins.
Which of the cell organelle lacks membrane?
Mesosome
Mitochondria
Ribosome
Liposome
C.
Ribosome
Ribosomes are the granular structures, composed of ribonucleic acid (RNA) and proteins acid and hence, are not surrounded by any membrane. They were first observed by George Palade (1953) under the electron microscope as dense particles. The eukaryotic ribosomes are 80S, while the prokaryotic ribosomes are 70S.
Chromosome is made up of
DNA and pectin
RNA and DNA
DNA and histone
only histone
C.
DNA and histone
In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.
Cell theory is not applicable for
bacteria
fungus
algae
virus
D.
virus
Cell theory was given by Theodor Schwann, Mathias Schleiden and Rudoplh Virchow. The cell theory states :
(i) All living organisms are composed of cells. They may be unicellular or multicellular.
(ii) The cell is the basic unit of life.
(iii) Cells arise from pre-existing cells.
The modem version of the cell theory includes the ideas:
1. Energy flow occurs within the cells.
2. Hereditary information (DNA) is passed on from cell to cell.
3. All cells have the same basic chemical composition.
State four important functions of plasma membrane.
The main difference between Gram positive and Gram negative bacteria is
cell membrane
cell wall
ribosome
mitochondria
B.
cell wall
The main difference between Gram positive and Gram negative bacteria is the cell wall. The cell wall of Gram negative bacteria contain peptidoglycan (10%), lipopolysaccharides, lipoprotein and phospholipid, while cell wall of Gram positive bacteria contain peptidoglycan (60-90%), teichoic acid and lipids.
What is a genophore?
DNA in prokaryotes
DNA and RNA in prokaryotes
DNA and protein in prokaryotes
RNA in prokaryotes
B.
DNA and RNA in prokaryotes
The characteristic feature of bacterial nucleus is absence of nuclear membrane, nucleolus and nuclear sap and such a nnucleus is called nucleoid or genophore. It contains DNA and RNA.
Electrons used in electron microscope are of the wavelength
0.05 Å
0.15 Å
0.25 Å
0.30 Å
A.
0.05 Å
In electron microscope the source of radiation is electrons of wavelength of about 0.05 Å (0.005 nm). The electrons are emitted and accelerated in a vaccum tube and the electron beam is deflected by electromagnetic coils acting as condensor, objective and projector lenses.
Which one of the following human cells do not contain mitochondria?
Nerve cell
Red blood cell
Liver cell
White blood cell
B.
Red blood cell
Human cells does not contain neither nucleus nor mitochondria. Due to which these cells use none of the oxygen they transport. They produce the enrgy carrier ATP from glucose by a glycolysis pathway that ends with lactic acid production.
Which one of the following cells is not a phagocytic cell?
Macrophage
Monocyte
Neutrophil
Basophil
D.
Basophil
Basophils are non-phagocytic in nature. There number increase in chicken pox. These represent mast cells of connective tissue.
Numerical aperture of microscope lens is expressed by
angular aperture only
refractive index only
both angular aperture and refrative index
wave length of the light used
C.
both angular aperture and refrative index
Numerical aperture is the multiple of refractive index of medium (n) and sine of angle subtended by optical axis and outer ray covered by objective (sin ).
Numerical aperture (NA) = n sin
N-acetyl muramic acid is found in
cell wall component of plant
cell wall component of Gram positive bacteria
cell wall component of fungi
viral coat material
B.
cell wall component of Gram positive bacteria
The bacterial cell wall is composed of protein-lipid-polysaccharides with two important chemical components as-NAG (N-acetyl glucosamine) and NAM (N-acetyl muramic acid).
Identify the bacterium that appears violet after Gram staining
Salmonella enterica
Escherichia coli
Mycobacterium tuberculosis
Rhizobium meliloti
C.
Mycobacterium tuberculosis
Mycobacterium tuberculosis is a Gram positive bacterium that appears violet after Gram staining.
Salmonella enterica is a Gram negative bacterium.
Escherichia coli is a Gram negative bacterium.
Rhizobium meliloti is a Gram negative bacteria.
A major site for synthesis of lipids is
RER
SER
symplast
nucleoplasm
B.
SER
The Smooth Endoplasmic Reticulum (SER) is the major site for synthesis of lipids. RER is actively involved in protein synthesis and secretion. Nucleoplasm is the site for active ribosomal RNA synthesis. Symplast is the system of interconnected protoplast through, which water movement occurs.
Which of the following is not correctly matched for the organism and its cell wall degrading enzyme?
Bacteria - Lysozyme
Plant cells - Cellulase
Algae - Methylase
Fungi - Chitinase
C.
Algae - Methylase
In algae, cell wall is made up of cellulose degraded by cellulase enzyme. Bacteria have lysozyme, plants cells have cell wall degraded by cellulose and fungi have chitinase.
The Golgi complex plays a major role
in trapping the light and transforming it into chemical energy
in digesting proteins and carbohydrates
as energy transferring organelles
in post translational modification of proteins and glycosidation of lipids
D.
in post translational modification of proteins and glycosidation of lipids
Golgi complex plays a major role in post translational modification of proteins and glycosidation of lipids. Chloroplasts contain chlorophyll, which traps light and transform into chemical energy. Lysosomes are
involved in digesting proteins, fats and carbohydrates. Mitochondria are energy transferring organelles.
Which one of the following organelle in the figure correctly matches with its function?
Rough endoplasmic reticulum, formation of glycoproteins
Golgi apparatus, protein synthesis
Golgi apparatus, formation of glycolipids
Rough endoplasmic reticulum, protein synthesis
D.
Rough endoplasmic reticulum, protein synthesis
Rough Endoplasmic Reticulum (RER) - Protein synthesis
Smooth Endoplasmic Reticulum (SER) - Lipid synthesis.
Golgi apparatus - Important site of formation glycoproteins and glycolipids.
The primary cell wall is mainly made up of
lignin
pectin
cellulose
protein
C.
cellulose
Primary cell wall is the part or layer of cell wall in which cell growth is permitted. It is mainly composed of cellulose. Secondary cell wall is composed of lignin, while the middle lamella is rich is pectin.
In the primary cell wall, major carbohydrates are cellulose, hemicellulose and pectin. The cellulose microfibrils are linked via hemicellulosic tethers to form the cellulose- hemicellulose network, which is embedded in the pectin matrix.
Which of the following is always absent in prokaryotic cells?
Ribosome
Mitochondria
DNA
Cell wall
B.
Mitochondria
A typical prokaryotic cell i.e. bacterial cell has cell wall just below the glycocalyx composed of peptidoglycan. They also have ribosomes and DNA just like eukaryotes. Prokaryotic cell does not have mitochondria to generate energy. They, instead generate few energy or ATP via glycolysis (when oxygen is available) and lactic acid fermentation (when oxygen is unavailable).
Objects less than 0.2 m in size cannot be see an under light microscope because
the wave length of visible light is 3900- 7800 Å
only two types of lenses are used
maximum magnifying power of ocular lens is 20 X
maximum magnifying power of objective lens is 100 X
A.
the wave length of visible light is 3900- 7800 Å
Light microscopy employs visible light to detect small objects. It has the ability to magnify an object upto 1000 times. High quality light microscopes generally allow viewing of bacterial cells too. The light microscope cannot view viruses or other tiny objects about or less than 0.2 µm because it does not allow to view objects smaller than the wavelength of visible light (3900-7800 Å). Thus, to view extremely small or tiny object scientist preffered to use electron microscopy.
Pseudopodia are produced by
plasma cell
mast cell
adipose cell
fibroblast cell
D.
fibroblast cell
Pseudopodia are temporary cytoplasm-filled projections of the cell wall that certain eukaryotic cells use for motion or for ingesting nutrients. Most cells with this capability are referred to as amoeboids.
Several pseudopodia arise from the surface of the body. Protoplasmic processes of fibroblast can acts as pseudopodia supported by axial filaments.
The apoplast is located
outside the plasma membrane
in the entire cytosol
on both sides of plasma membrane
in the plastidial content
A.
outside the plasma membrane
The apoplast is free diffusional space outside the plasma membrane formed by the cell wall and intercellular space between cells that surrounds the symplast. It is interrupted by the casparian strip in roots, by air spaces between plant cells and by the plant cuticle. It is important for all the plant's interaction with its environment.
ATP synthesis in cell requires
H+ gradient across the membrane
K+ gradient across the membrane
PO4 3- gradient across the membrane
Ca2+ gradient across the membrane
A.
H+ gradient across the membrane
ATP synthesis takes place by the process of chemiosmosis, where ATP is generated via a proton (H+) gradient across the membrane.
Actions of the proton pump is the driving force of ATP. The proton pump pumps H+ ions across the membrane. It establishes a chemical gradient; the protons are high in the intermembrane space than in the matrix. Pumping of the H+ ions across the membrane makes the intermembrane space more positively charged as compared to the matrix. Hence, this is strong electrochemical gradient which energizes the ATP synthase protein to form ATP.
The eukaryotic cells have all of the followings except
peptidoglycan in the cell wall
the 80 S ribosome
nuclear membrane
mitochondria
A.
peptidoglycan in the cell wall
Peptidoglycan or murein in the cell wall is specific only to prokaryotes. This rigid structure gives the cell shape and surrounds the cytoplasmic membrane. Peptidoglycan is a huge polymer of disaccharides (glycan) cross-linked by short chains of identical amino acids (peptides) monomers. The backbone of the peptidoglycan molecule is composed of two derivatives of glucose: N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM).
Peroxisomes have
ribosome
DNA
catalase enzyme
centrosome
C.
catalase enzyme
Peroxisomes (microbodies) are small rounded organelles found free floating in the cell cytoplasm. These structures contain at least 50 enzymes and are separated from the cytoplasm by a lipid bilayer single membrane barrier. They are called peroxisomes because they all produce hydrogen peroxide. Peroxisomes produce large amount of the enzyme catalase that breakdown hydrogen peroxide to water and oxygen.
Two membrane envelops is found in
mitochondria, Golgi apparatus and chloroplast
mitochondria, nucleus and chloroplast
nucleus, Golgi apparatus and endoplasmic reticulum
nucleus, ribosome and chloroplast
B.
mitochondria, nucleus and chloroplast
Eukaryotic cells such as animal cells have membrane bound organelles. They are of two types:
(i) Double membrane bound organelles- Mitochondria, nucleus, chloroplast, endoplasmic reticulum and Golgi body.
(ii) Single membrane bound organelles- Lysosomes, peroxisomes, vacuoles
Genes for maternal inheritance are located in
Golgi bodies
mitochondria
lysosome
nucleolus
B.
mitochondria
Mitochondria consists genes responsible for maternal or cytoplasmic gene inheritance. In most of the organisms, the mitochondrial genome is inherited maternally. This is because the mothers egg cell donates the majority of cytoplasm to the embryo and mitochondria inherited from the father's spemi are usually destroyed.
Which of the following features is/are correct for heterochromatin of eukaryotic nucleus?
It is highly expanded in interphase
It stains densely with basic dyes
It is highly condensed in interphase
It stains densely with acidic dyes
B.
It stains densely with basic dyes
C.
It is highly condensed in interphase
Heterochromatin is a tightly packed from of DNA, that stains intensely. Both centromeres and telomeres are heterochromatic. Heterochromatic telomeres remains condensed during interphase where as 'euchromatin' decondenses during interphase. DNA is acidic in nature and therefore stains basic dyes. Loosely coiled chromatin (euchromatin) stainslightly with basic dyes whereas tightly coiled DNA (heterochromatin) stains darkly with basic dyes.
Identify the type of flagella Column I based on there structures given in Column II.
| Column I (Flagella type) | Column II (Structure) |
| A. Monotrichous | 1.  |
| B. Amphitrichous | 2.  |
| C. Lophotrichous | 3.  |
| D. Peritrichous | 4.  |
A - 1; B - 2; C - 3; D - 4
A - 2; B - 1; C - 4; D - 3
A - 4; B - 3; C - 2; D - 1
A - 4; B - 1; C - 2; D - 3
C.
A - 4; B - 3; C - 2; D - 1
The number and distribution of flagella on the bacterial surface are characteristics for a given species, based on this flagella can be
A. Monotrichous - A single flagella that extends from one end of the cell.
B. Amphitrichous - A single or multiple flagella that extends from both ends of the cell.
C. Lophotrichous - Multiple or several flagella that extends from one or both ends of the cell.
D. Peritrichous - Multiple flagella may be randomly distributed over the entire bacterial cell.
Identify the correct pair of combinations
I. Schwann - Omnis cellula-e-cellula
II. Ochoa - Polynucleotide phosphorylase
III. Taylor - Semiconservative replication of DNA
IV. Flemming - Ribosomes
II, III
III, IV
II, IV
I, III
A.
II, III
Statement II and III are correct. Statement I and IV can be corrected as follows:-
(I) Schwan - Cell theory
(IV) Flemming - Discovery of penicillin
A feature of peroxisome in our body is
they are associated with synthesis and storage of lipids
they contain oxidising enzymes and promotes gluconeogenesis
they contain oxygenase a detoxification enzyme
they are not found in intact cells
B.
they contain oxidising enzymes and promotes gluconeogenesis
Peroxisomes are small, membrane-enclosed organelles that contain enzymes involved in a variety of metabolic reactions, including several aspects of energy metabolism. Peroxisome contains oxidising enzymes and promote gluconeogenesis. The participation of this organelle affords the potential of alternative pathways for the conversion of triacylglycerols to glucose and for the conversion of amino acids and lactate to carbohydrate.
One key function of nuclear pores is to
aid in the production of new nuclei
allow cells to communicate with each other
form connections between different organelles
allow molecules like protein to move in and out of the nucleus
D.
allow molecules like protein to move in and out of the nucleus
Nuclear pores are large protein complexes that cross the nuclear envelope, which is the double membrane surrounding the eukaryotic cell nucleus. The main function of nuclear pores is to allow molecules like protein to move in and out of the nucleus.
Function of SER is
protein metabolism
lipid metabolism
carbohydrate metabolism
catabolic activity
B.
lipid metabolism
SER or Smooth Endoplasmic Reticulum is an organelle present in both animals as well as plants. The function of SER is lipid metabolism. It does not contain ribosomes and is specialised to synthesize lipids and steroids.
RER or Rough Endoplasmic Reticulum is attached with ribosomes on its surface and its main function is in protein synthesis.
Which ion is used in the protoplast fusion with the PEG (polyethylene glycol)?
Na+
Ca++
K+
Mg+
B.
Ca++
Ca++ is used with PEG in chemical method for fusion of two cells (i.e., protoplast) as Ca penetrate the plasma membrane comprehensively and allow the genetic material to transfer from one cell to other.
The endosymbiotic hypothesis of mitochondrial origin states that
mitochondria were capable of self-duplication
mitochondria were initially aerobic bacteria
mitochondria were chloroplast in the beginning
mitochondria were part of nucleus
B.
mitochondria were initially aerobic bacteria
According to endosymbiotic hypothesis of mitochondria by Hilman, mitochondria were initially free-living, aerobic bacteria which during the process of evolution, got entrapped in larger eukaryotic cells. Where they then transformed into their useful inseparable components in due course of time.
A function of lysosomes is
replication
hydrolysis
respiration
None of the above
B.
hydrolysis
Lysosomes is a simple spherical sac surrounded by a single membrane. They contain digestive or hydrolytic enzymes synthesised by RER.
Mitochondria and chloroplasts are similar because
both have 80S ribosomes
both have nuclei
both have single membrane envelope
both have DNA
D.
both have DNA
Both are semi-autonomous organelles. Both of these possess circular DNA.
Golgi body is
organ for protein synthesis
secretory organ
Both (a) and (b)
None of the above
B.
secretory organ
Golgi bodies are secretory organ of the cell. In golgi apparatus, protein glycosylation takes place.
Lampbrush chromosomes are present in
Drosophilla
Ascaris
Hydra
None of these
D.
None of these
Lampbrush chromosomes are found in the vertebrate oocytes particularly rich in yolk. They are extremely large and brush like in appearence.
Nucleated RBCs are present in which
Rabbit
Camel and llama
Embryo of human
Both (a) and (b)
A.
Rabbit
Nucleated RBCs are found in Camel and Leama, which is an exception in biology.
The enzymes found in lysosomes are
hydrolytic enzymes
proteases enzymes
lipases enzymes
cellulases enzymes
A.
hydrolytic enzymes
Lysosome contains about 40 hydrolytic enzymes like proteases, nucleases, glycosidases, lipases, phospholipases, phosphatases and sulphatases.
Chromosome was discovered by
Hofmeister
Muller
Flemming
Hammerling
A.
Hofmeister
Hofmeister (1848) discovered the chromosome in pollen mother cell of Tradescantia.
Which of the following is not the function of 'Golgi body'?
Protein synthesis
Formation of cell wall
Formation of fatty acids
Formation of plasma membrane
A.
Protein synthesis
Protein synthesis is not the function of Golgi body.
The significance of mitochondria was given by
Flemming
Meves
Schwann
Altman
D.
Altman
Significance of mitochondria was given by Altmann. The important role of mitochondria is to produce energy currency of the cell, i.e. phosphorylation of ADP, through respiration and to regulat cellular metabolism.
Mitochondria contains
only DNA
DNA and RNA
only RNA
None of the above
B.
DNA and RNA
Mitchondria consists of DNA, RNA and ribosome. Hence, it is known as semi- autonomous body.
Which of the following shows minimum number of chromosomes?
n : 1
n : 2
n : 3
n : 4
A.
n : 1
Minimum number of chromosomes are present haploid, i.e. n : 1.
Who proposed 'fluid mosaic model' of plasma membrane?
Singer and Nicholson
Robertson
Benneson
None of the above
A.
Singer and Nicholson
Singer and Nicholson proposed fluid mosaic model of plasma membrane. According to this model, there is a lipid bilayer in which the protein molecules are embedded. The lipid bilayer gives fluidity and elasticity to the membrane.
Fluid mosaic model exhibits amphipathy because of
glycoproteins
phospholipids
lipids
glycolipids
B.
phospholipids
Fluid mosaic model exhibits amphipathy. It is due to phospholipids as they have both hydrophobic and hydrophilic groups.
The controlling centre of cell is
nucleus
nucleolus
mitochondria
ribosome
A.
nucleus
Hammerling proved that nucleus is the main controlling centre of cell while working on Acetabularia.
Chromosomes in a bacterial cell can be 1 to 3 in number and
are not circular or linear
can be circular as well as linear within the same cell
are always circular
are always linear
C.
are always circular
Bacterial chromosomes are circular DNA molecules.
Which of the following is a single membranous structure?
Lysosome
Nucleus
Mitochondria
Chloroplast
A.
Lysosome
Lysosomes are 0.2 to 0.8 in size, spherical or irregular membranous vesicles. It consists of hydrolytic enzymes that can break down many kinds of biomolecules.
A prokaryotic cell lacks
true nucleus
nuclear membrane
membrane bound organelles
All of the above
D.
All of the above
In Prokaryotes, absence of true nucleus is found. Instead, a circular double- stranded DNA molecule occurs as a genetic material which is not associated with RNA and histones to form chromosomes. Also, only few organelles such as 70S ribosomes and reserved bodies are occured in the cytoplasm.
Passive food ingestion in Amoeba is known as :
import
invagination
circumfluence
circumvallation
A.
import
Import involves passive sucking of food into body by rapture of plasmalemma e.g., ingestion of algae.
Principle protein of cillia and flagella is :
globulin
fibrin
flagellin
tubulin
D.
tubulin
Axoneme is the microtubular structure of cilia and falgella. The axoneme is composed of variety of proteins such as and tubulins dynein and nexin etc.
Active transport occurs :
against concentration gradient and requires ATP
against concentration gradient and does not require ATP
along concentration gradient but require ATP
along concentration gradient but does not require ATP
A.
against concentration gradient and requires ATP
Active transport uses specific proteins called pumps, which use metabolic energy(ATP) to move ions or molecules against their concentration gradient. Common examples of active transport are Na+ - K+ ATPase. Ca++ ATPase and proton pump.
Energy currency (reservoir) of the cells is:
AMP
ATP
RNA
DNA
B.
ATP
Energy currency of the cell is ATP or Adenosine triphosphate. Last two phosphate bonds in ATP are called energy rich bonds.
निम्नलिखित गद्यांश को पढ़कर पूछे गए प्रश्नों के उत्तर दीजिये:-
हॉर्टीकल्चर डिपार्टमेंट का सेक्रेटरी साहित्य-प्रेमी आदमी जान पड़ता था। उसने लिखा था- “आश्चर्य है, इस समय जब हम ‘पेड़ लगाओ’ स्कीम ऊंचे स्तर पर चला रहे हैं, हमारे देश में ऐसे सरकारी अफसर मौजूद हैं, जो पेड़ों को काटने का सुझाव देते हैं, और वह भी एक फलदार पेड़ को. और वह भी जामुन के पेड़ को, जिसके फल जनता बड़े चाव से खाती है। हमारा विभाग किसी हालत में इस फलदार वृक्ष को काटने की इजाजत नहीं दे सकता।”
1. हार्टीकल्चर डिपार्टमेंट की क्या टिप्पणी थी?
2. उपर्युक्त विभाग किस बात की इजाजत नहीं दे सकता?
3. उपर्युक्त गद्याशं से किस मनोवृत्ति का पता चलता है?
1. हार्टीकल्चर डिपार्टमेंट का सेक्रेटरी साहित्य प्रेमी प्रतीत होता था। अत: वह पेड़ को काटने के हक में न था। उसका तर्क था कि हम पेड़ लगाने का अभियान चला रहे हैं, ऐसे में किसी सरकारी अफसर का पेड़ काटने का सुझाव हास्यापद है।
2. उपर्युक्त विभाग अर्थात् हार्टीकल्चर डिपार्टमेंट इस बात की इजाजत नहीं दे सकता कि इस फलदार वृक्ष को काट दिया जाए। यह रसीले फल वाला जामुन का पेड़ है। इसके फल जनता बड़े चाव के साथ खाती है। यह अत्यंत उपयोगी पेड़ है। इसे किसी भी हालत मै नहीं काटना चाहिए।
3. उपर्युक्त गद्यांश से सरकारी लालफीताशाही का पता चलता है। सरकार के विभिन्न विभागों में आपसी तालमेल का अभाव है। एक विभाग दूसरे विभाग को नीचा दिखाने के प्रयास में लगा रहता है। सभी विभाग प्राय. अनिर्णय की स्थिति में रहते हैं। किसी भी समस्या की जिम्मेदारी वे दूसरे विभाग पर डालकर अपना पलना झाडू लेते हैं। यही कारण है कि कोई काम नहीं होने पाता।
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