Biology Chapter 1 The Living World

The huge diversity found in the living beings and the vast number of organisms make their study very difficult. It is almost impossible to study each organism separately. Classification helps in the systematic study of the living beings. Therefore, the biological classification helps in revealing the relationship between various organisms. It also helps in making the  study of organisms easy and organized.

To classify a class of forty students, let us start the classification on the basis of sexes of the students. This classification will result in the formation of two major groups- boys and girls. Each of these two groups can be further classified on the basis of the name and surnames.

Since there is still some chance that more than one student can have the same surname, the final level of classification will be based on the roll numbers of each student.

The knowledge of characteristics of an individual or its entire population helps in the identification of similarities and dissimilarities among the individuals of the same kind or between different types of organisms. It helps to classify organisms in various categories depending upon these similarities and dissimilarities.

Taxa is the scientific term for each unit or category of classification. It indicates categories at different levels.

Both (a) and (c) represent correct sequences of taxonomic categories as the correct hierarchical arrangement of taxonomic categories in ascending order is

Species → Genus → Family → Order → Class → Phylum → Kingdom

Key is a taxonomical aid that helps in identification of plant and animal species. These keys are based on similarities and dissimilarities in characters, generally in a pair called couplet.

Each statement in a taxonomic key is referred to as a lead. For categorizing each taxonomic rank, such as family, genus, species, etc., different keys are used. It is also useful in identification of unknown organisms.

Keys are of two types- indented and bracketed keys.

Key are analytical in nature and help to identify the differences between species and identify new species. 

Taxonomic hierarchy is the arrangement of various taxa in a hierarchical order. In the hierarchy, species is present at the lowest level whereas kingdom is present at the highest level.

A Taxonomic hierarchy

Classification of a plant

As an example, let us classify Magnifera indica (Mango).

Kingdom – Plantae

Division – Angiospermae

Class – Dicotyledonae

Order – Sapindales

Family – Anacardiaceae

Genus – Magnifera

Species – indica

Classification of an animal

As an example, classification  MAN

Kingdom – Animalia

Phylum – Chordata

Class – Mammalia

Order – Primata

Family – Hominidae

Genus – Homo

Phylum

Phylum is second highest unit of classification after Kingdom. It includes one or more related classes of animals. In plants, instead of phylum, the term ‘division’ is used.

Class - Class is a taxonomic group consisting of one or more related orders. For example, the class, Mammalia, includes many orders like Primata (Man), Carnivora(Lim, tiger) etc.

(iii) Family - Family is a taxonomic group containing one or more related genera eg. Family hominidae contains Apes, Monkeys and Man. In plants, families are categorized on the basis of vegetative and reproductive features.

Order -Order is a taxonomic group containing one or more families. For example, the order, carnivora, includes many families.

Genus - Genus is a taxonomic group including closely related species. For example, the genus, Solanum, includes many species such as nigrum, tuberosum, etc.

A.

Will decrease

C.

Diversity of kinds of organisms and their relationship

Classification

Herbarium

Manuals

Keys

Class

Systema Naturae. 

Couplet

sapiens

Specific epithet.

ICZN stands for International Code for Botanical Nomenclature. 

Couplet in a key represents the choice made between two opposite options. 

Monograph is that means of recording descriptions which contain the information of only one taxon

In amoeba, the reproduction is synchronous with the growth. Amoeba is a single celled organism in which the increase in the number of cells or mass is considered to be growth as well as reproduction. After mitosis, there is no growth in size rather two new organisms are formed. The parent divides into two and forms two new daughter cells. Hence formation of new cells is considered to be reproduction. 

Metabolism is the sum total of the chemical reactions occurring in the body. 

The largest botanical garden in the world is - Royal botanical garden in England, Kew.

NBRI (National Botanical Research Institute ) and Indian Botanical Gardens Kolkata are the two well-known botanical gardens in India. 

Large animals like birds and mammals are usually stuffed and preserved. 

Growth cannot be taken as the definite property of the living organisms. Even a non-living thing grows by the accumulation of matter over the time, but it does not fulfill the other criteria like reproduction, metabolism, and consciousness. Similarly, the growing ball of snow does not fulfill the other criterions and thus is considered to be non-living. 

Fossils are the remains of an organism or some part of the anatomy of once-living things, older than our recent geographical time. They are a record of the evolution of life through geologic time. The study of fossils is known as Paleontology. 

The role of botanical gardens

i. They provide plant material for taxonomic studies.

ii. Different species are grown for identification and research.

iii. It helps in the maintenance of the record of the flora.
iv. These provide plants, good environment and care for growth and development.
v. The plants are used to carry out selective breeding to maintain continuity of particular species. 

The aim of the zoological parks are :

To develop interest and awareness about wild animals in public.

To conserve and protect the endangered species of animals. 

a. The common name of Brassica campestris is mustard.

b. The first two name denotes the genus and the species.
‘Brassica’ represents the genetic epithet of the plant whereas the ‘campestris’ denotes the specific epithet of the plant belongs.

c. The scientific or bionomial names are always written in italics to show their Latin origin. Moreover, it is a rule to write the scientific names in italics. 

d. The term 'linn' denotes that the species was first described by Carolus Linnaeus. 

D.

Herbarium

Herbarium

C.

Division

C.

Collection of endemic and exotic living species

C.

Both a & b

D.

All of above

D.

Response to external stimuli

Genus - Homo

Lucknow

Taxonomical Aids are the procedures, methods or techniques to store and preserve the information as well as the specimen. They help in the study of the classification of the diverse groups of organisms present. These help in the taxonomical study of various species of plants, animals and the other organisms useful in agriculture, forestry, industry and in general in knowing our bio-resources. 
Herbarium and Botanical gardens are some of the taxonomical aids used by the scientists. 
Herbarium is a storehouse of collected plant specimens that are dried, pressed and preserved on sheets. 
Botanical garden - are specialised gardens have collections of living plants for reference . Plant species in these gardens are grown for identification purposes. Each plant is labelled, indicating their scientific name and family. 

Biodiversity is the term used for all the life forms which encompass all the organisms on the Earth. Thus when we are taking a small geographical area into consideration it will be a case of diversity and not biodiversity. 

As per the code provided by the ICBN the scientists follow the following hierarchy of classification while classifying plants:

Such plants variants are known as Biotypes. All the biotypes are similar genetically but are different morphologically. The difference in the morphology is due to the abiotic factors like temperature, soil quality, climate, water availability etc. The difference in the abiotic conditions is due to the altitudinal gradient. Therefore the plant species show differences in morphology due to the altitude gradient. 
When these plants are grown in similar conditions , there is no difference in the abiotic factors and hence all are similar in morphology. 

Family

Tips: -

The following steps have to be followed in order to prepare  an herbarium sheet. 
i. Collection of the species.
ii. Pressing - The specimen is spread and pressed by keeping it in between the two sheets of paper in order to preserve the specimen
iii. Drying - The spread specimen is dried under the sun. 
iv. Poisoning - The specimen is treated with anti-fungal treatment to preserve it for a longer duration. 
v. Mounting - The specimen is then mounted over a herbarium sheet.
vi. Labelling - The specimen is labelled by mentioning the classification and the complete information.

The different tools used while preparing the herbarium sheet are :
Knife, digger, pruning Knife, sickle, blotting paper, Old newspaper or magazines, plant press, field noteboooks, herbarium sheets, glue, labels etc. 

The sum of the plant species in a given geographical are is known as the Flora. 
The sum of the animal species in the given geographical area is known as the Fauna of that area.
Th term vegetation takes into account a bigger geographical area. In many cases, the term is used for all the plants on a global scale.
Endemic species are those which are found only in a particular geographical area. Rauvolfia is found only in a particular area thus is endemic to that area.
Exotic species  are those species which are not naturally found in the particular area but are introduced there because of careful selection and breeding. Eichornia crassipes was introduced and was not normally found. 

Brinjal and potato belong to the same genus Solanum. This is because both of them show the common characteristics found in the plants of the genus Solanum - like Phyllotaxy, venation, inflorescence etc. However, breeding is not possible between the two species of brinjal and potato. Since species are a group of organism that is capable of interbreeding thus, brinjal and potato are considered to belong to two different species. 

The cells usually have the same composition and the are made of similar molecules. All the molecules together in a particular fashion build up different cell organelle with specific functions. The constituents remain the same but the outcome or final product, function and purpose changes. Hence, properties of the cell organelles are not always found in the constituents

The properties of the tissues are not the constituent of the cells. 
a. A muscle tissue is capable of contraction but all its constituent cells may not be capable of doing so.
b. The skeletal system is composed of bones and cartilage. A bone is hard, but its constituents many not exhibit similar properties. 
c. Blood is capable of carrying oxygen but the white blood cells are not capable in spite of being a constituent of blood. 

D.

Biological names can be written in any language

Biological names originate from Latin laguages. 

C.

A museum has collection of photographs of plants and animals

Museums have a collection of preserved plants and animal specimens for study and reference specimens are preserved in the containers in preservative solutions.
Herbarium is a store house at collected plant specimens that are dried, pressed and preserved on sheets.
Botanical gardens have a collection of living plants for reference.
The key is a taxonomic aid for identification of plants and animals based on the similarities and dissimilarities.

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

B.

Plasmodium falciparum – A protozoan pathogen causing the most serious type of malaria

According to binomial nomenclature the scientific name is consist of genus and species. The genus name is started with capital letter and both the word Latinized. Musca domestica is European housefly. It belongs to phylum-Arthropoda.
E.coli is having full name Escherichia coli a commonly occurring bacterium in human intestine.
Panthera tigris is Indian tiger and protected in Gir forest.

ICBN = International code of Botanical Nomenclature.

B.

Rhodospirillum – Mycorrhiza

C.

Mycoplasma

D.

Bacteria

Spliceosomes are used in removal of introns during post-transcriptional processing of hnRNA in eukaryotes only as split genes are absent as prokaryotes.

B.

Volvox

C.

Ribosome

Mesosomes will be equivalent to mitochondria of eukaryotes because of respiratory enzyme present in aerobic bacteria.

D.

Hexaploid

The common bread wheat (Triticum aestivum) is an allohexaploid, which has two copies of each of the genomes A, B and D. Its somatic complement is represented by AABBDD.

A.

Venter wall of archegonium

Calyptra is a covering developed from the ventre of archegonium in bryophytes and pteridophytes. It acts as a transpiration shield around the immature capsule and provides protection to the young capsule.

B.

Funaria

Protonema is the juvenile stage of moss resulting from the germinating meiospore and consists of a slender, green, branching system of filaments. In Funaria, the protonema stage is only vegetative and transitory, which precedes the upright, leafy gametophyte.

A.

Curing high blood pressure

Alkloid reserpine is obtained from the root of Rauwolffia serpantina. It is used to cure high blood pressure.

D.

A – 3; B – 1; C – 4; D – 2

C.

Jim Corbett

National Park is an area strictly reserved for the betterment of wildlife and other activities like forestry. The first National Park was Jim Corbett National Park established in 1935.

B.

Kaziranga National Park

Rhino (Rhinoceros unicomis) are protected in Kaziranga National Park. This park is situated in Assam.

Gir National Park protects Lions and is situated in Gujarat.

Bandipur National Park is a tiger reserve located in Karnataka.

Ranthambore National Park is also a tiger reserve known for protecting Bengal tigers and is situated in Rajasthan.

A.

Linnaeus

' Systema Naturae' was written by Carolus Linnaeus. He is the Father of Taxonomy.

D.

A B C D E

3 1 4 5 2

D.

Gene flow does not occur between the populations of a species

Gene flow means the spread of genes through populations as affected by movements of
individual and their propagules e.g., spores, seeds etc. It ensures that all populations of a given species share a common gene pool i.e., it reduces difference between populations. The interruption of gene flow between populations is a pre-requisite for the formation of new species.

B.

they allow ex situ conservation of germplasm

A Botanical garden is a collection of various types of living plants. Ex situ conservation means conservation of plants or animals in the artificial habitats, which are quite similar to the normal habitats of these organisms. In this way botanical gardens provide ex situ conservation of germplasm.

C.

virus

Virus is without necessary metabolic enzymes, hence, free virus are inert particles incapable of any vital activities and uses host machinery. Virus is regarded as obligate parasite and have characteristic of both living and non-livings.

B.

Kerala

Periyar sanctuary is located in Kerala. Important animals found here are elephant, tiger, wild bear, sloth bear, grey hornbill etc.

A.

If both assertion and reason are true and reason is the correct explanation of assertion.

Consciousness is awareness of the surroundings and responding to external stimuli. The external stimuli can be physical, chemical or biological. All organisms, from primitive prokaryotes to most advanced and complex eukaryotes, are able to sense and respond to environmental factors. Consciousness is thus said to be the defining property ofliving organisms.

C.

sea pen and sea fan

Stinging cells are used for offence and defence. They have nematocysts, composed of capsule, shaft and thread tube. The thread tube coils around the prey or attaches to it and injects a toxin called hypnotoxin which paralyzes the victim. They are found in cnidarians- sea pen (Pennatula), sea fan (Gorgonia) etc.

D.

8.1%

The total number of species estimated is about 1.74 million. Out of these , species in India is roughly 8.1%. India with about 45000 species of plants and twice as many species of animals is one of the 12 megadiversity countries of the world.

B.

Nelumbo (lotus)

Non-native or alien species are often introduced accidently for their economic and other uses. They often become invasive ' and drive away the local species. Therefore, these species are second major cause of extinction.

Lantana camara has replaced many species in forests of Central India.

Parthenium hystero- phorus has pushed out various shrubs and herbs from open places in the plains. 

Water hyacinth Eicchornia crassipes is used in India to reduce pollution.

A.

heart

Cardiac muscle fibres are found in the wall of heart. They have dark intercalated discs at intervals. These are the specialized regions of cell membranes of two adjacent fibres. They permit the wave of muscle contraction to be transmitted from one cardiac fibre to another.

C.

Amphibians and algae

External fertilization is the fertilization that occurs outside the body of the organism. It requires an external medium such as water for its fertilization.Thus, in most aquatic organisms such as a majority of algae, fishes and amphibians, this type of fertilization occurs.

C.

Angiosperms

Endosperm nourishes embryo in seed plants. In gymnosperms, it represents the female gametophyte and is haploid (n). In angiosperms, it is a special tissue which is formed as a result of fusion of a male gamete with diploid secondary nucleus of the central cell. The fusion product is primary endosperm cell having a triploid (3n) endosperm nucleus.

D.

Conclavin-A, morphine, codeine, vinblastin

Secondary metabolites are derivatives of primary metabolites which have no direct function in growth and development of plants. These compounds arc accessory rather than central to the functioning, e.g., arbrin, cellulose, gums, diterpenes, carotenoids, curcumin, rubber etc. Arginine, tyrosine, glycine, serine and phenylalanine are amino acids, which are primary metabolites.

D.

S phase

S- phase or Synthesis phase is the phase where DNA replication takes place. It takes place on the template of the existing DNA and thus, the amount of DNA per cell doubles. If the initial amount of DNA is denoted as 2C, then it increases to 4C.

C.

C₄ plants does not carry photorespiration

Presence of photorespiration is a wasteful and energy consuming process in crop plants which ultimately leads to reduction in final yield of crops.  During C₃ photosynthesis, upto 50% of the CO₂ fixed may have to pass through photorespiratory process, thereby resulting in considerable decrease in photosynthetic productivity. In C₃ plants, there is little loss of photosynthetic activity on account of photorespiration which is absent in C₄ plants and hence they have better productivity.

C.

Oxytocin is released by posterior pituitary.

Vasopressin decreases the amount of urine by increasing reabsorption of water from DCT and collecting tubules.It stimulates the contraction of walls of blood vessels.

Glucagon  stimulates liver to convert stored glycogen into glucose and thus raises the blood sugar level.

Thymus releases thymosin which aids in proliferation of T- lymphocytes.

D.

Methanogenic bacteria- Gobar gas formation

Aspergillus niger carries out fermentation to form citric acid.

Fungus Trichoderma polysporum produces cyclosporin through fermentative activity. 

Cyclosporin-A has antifungal, anti-inflammatory and immunosuppressive properties.

Saccharomyces cerevisiae (baker's yeast/brewer's yeast) is used in production of bread/alcohol.

Methanogenic bacteria carry out microbial decomposition of organic matter and aids in gobar gas production.

A.

A - (ii), B - (iii), C - (iv), D - (i)

Chara is a genus of charophyte green algae in the family Characeae. They are multicellular and resemble land plants as they have stem and leaf like structures.

Selaginella is the sole genus of vascular plants in the family Selagginellaceae. It consists of scaled leaves bearing a ligule and by having spores of two types.

Ectocarpus is a genus of filamentous brown alga that is a model organism for the genomics of muticellularity. 

Sphenopsida is a class of vascular plants with a fossil. Commonly known as horsetails. Found mainly in wet areas.

A.

Pepsin - Chief cells

Parietal cells (or oxyntic cells) secrete hydrochloric acid (HCl) and Castle's intrinsic factor.

Chief cells (or peptic cells) secrete gastric digestive enzymes as proenzymes such as pepsinogen and prorennin.

HCl helps in converting pepsinogen to pepsin.

Goblet cells secrete mucus which helps to neutralise acid in stomach and protects stomach wall against HCl action.

C.

Or an average, 25-30 gm of urea is excreted out per day.

Glucose and amino acids are reabsorbed in PCT by secondary active transport. Water, Sodium (Na) and Chloride ions are reabsorbed in OCT. It is permeable to water. Maximum reabsorption takes place within the PCT. Humans are ureotelic and excrete out 25-30 gm of urea per day.

B.

On land - Skin, buccal cavity

In frog three types of respiration occurs to suit its amphibious mode of life. These are cutaneous, buccopharyngeal and pulmonary respiration. Cutaneous respiration occurs through the thin, moist, highly vascular and naked skin. It takes place in water as well as on land. Buccopharyngeal respiration occurs on land via thin, vascular, moist lining of buccopharyngeal cavity. Pulmonary respiration takes place when the frog is outside the water. It occurs by lungs of adult frog.

A.

Monstera- Fibrous root

Fasciculated root is a type of adventitious root. In this case, roots are swollen which occur in clusters from lower nodes of stems, e.g, Asparagus, Dahlia, etc.

B.

only asexual stages are known

Deuteromycetes are commonly known as imperfect fungi because only the asexual or vegetative stages of these fungi are known. The deuteromycetes reproduce only by asexual spores known as conidia. The mycelium is septate and branched. Some members are saprophytes or parasites while a large number of them are decomposers of litter and help in mineral cycling. Some examples are Alternaria, Colletotriclmm and Trichoderma.

D.

promotes closure of stomata

Abscisic acid acts as a general plant growth inhibitor and an inhibitor of plant metabolism. ABA inhibits seed germination. ABA stimulates the closure of stomata in the epidermis and increases the tolerance of plants to various kinds of stresses. Therefore, it is also called the stress hormone.

D.

puffer fish

The majority of pufferfish species are toxic and some are among the most poisonous vertebrates in the world. In certain species, the internal organs, such as liver, and sometimes their skin, contain tetrodotoxin and are highly toxic to most animals when eaten; nevertheless, the meat of some species is considered a delicacy in Japan, Korea, and China when prepared by specially trained chefs who know which part is safe to eat and in what quantity.

B.

active transport

Sodium-potassium pump (Na-K) is a membrane transport protein that exchanges sodium ions (Na⁺) for potassium ions (K⁺). It transports 3 Na⁺ outwards for 2K⁺ into the cell, thus maintaining the differential concentrations of each ion across the plasma membrane. The process requires energy in the form of ATP, being a form of active transport.

D.

neither ATP nor sugar

Photorespiration is the light dependent process of oxygenation of ribulose biphosphate (RuBP) and release of carbon dioxide by the photosynthetic organs of a plant. Normally photosynthetic organs do the reverse in the light, i.e., uptake of CO₂ and release of O₂ At high temperature, RuBP carboxylase functions as oxygenase and instead of fixing carbon dioxide (C₄ cycle), oxidises ribulose 1, 5-biphosphate to produce a 3-carbon phosphoglyceric acid and a 2-carbon phosphoglycolate. Photorespiration does not produce energy or reducing power. Rather, it consumes energy. Further, it undoes the work of photosynthesis. There is 25% loss of fixed CO₂. Therefore, photorespiration is a highly wasteful process. This happens only in case of C₄ plants. C₄ plants have overcome the problem of photorespiration.

C.

phase contrast microscope

Phase contrast microscope was developed by Zemicke (1935, Nobel Prize 1953) to observe living cells and the events occurring in them (e.g., Spindle formation, movement of chromosomes, endocytosis, exocytosis). It is similar to optical microscope except that it has an annular diaphragm in the condenser and a transparent phase plate at the back focal plane of objective. The microscope converts differences in refractive indices into differences in brightness.

D.

D: Tectorial membrane

A- Basilar membrane
B- Scala media
C- Reissner's membrane
D- Tectorial membrane

C.

36

The net gain from complete oxidation of a glucose molecule in aerobic respiration is 36 ATP molecules. 10 molecules of NADH, (2 from Glycolysis + 8 from Krebs' cycle) yield = 10 x 3= .30 ATP, 2 molecules of FADH, yield = 2x 2 = 4 ATP and glycolysis also yields 2 ATP. Therefore, total release of ATP per hexose will be = 30 + 4 + 2 = 36 ATP.

A.

Tintin

Titin, also known as connectin, is a protein that, in humans, is encoded by the TTN gene.

C.

Guava, sunflower, strawberry

C.

A: PS I; B:PS II; C:e^- acceptor; D: LHC

A - Photosystem I (PS I)
B - Photosystem II (PS II)
C-e acceptor
D- LHC(Light Harvesting Complex).

A.

(i), (iii), (iv) and (v)

Muscle contraction is brought about by sliding of the actin filaments over myosin filaments. When a muscle fibril contracts, its A band remains constant and I band shortens. H zone also disappears as the actin filaments of both sides in each sarcomere may overlap each other at M line.

C.

Ca²⁺

When an impulse arrives at the synaptic knob of the axon, it depolarizes the presynaptic membrane and increases its permeability to calcium ions (Ca²⁺). Ca²⁺ ions from the synaptic cleft pass into the synaptic knob via voltage gated channels. Sudden rise in the cytosolic concentration of Ca, causes the release of a chemical, called neurotransmitter substance, from small synaptic vesicles present there into the synaptic cleft by exocytosis through the presynaptic membrane.

B.

C₄ plants

The C₄ plants are adapted to dry tropical regions and have greater productivity of biomass. They have special type of leaf anatomy known as Kranz anatomy. In this type of anatomy then bundle sheath cells form several layers around the vascular bundles; they are characterized by having a large number of chloroplasts, thick walls impervious to gaseous exchange and no intercellular spaces.

A.

inhibit spindle formation during mitosis

Colchicine is an alkaloid derived from the autumn crocus, Colchicum autumnale. It inhibits spindle formation in cells during mitosis so that chromosomes cannot separate during anaphase, thus inducing multiple sets of chromosomes. It does not affect cytokinesis.

B.

alertness

The adrenal medulla secretes two hormones called adrenaline or epinephrine and noradrenaline or norepinephrine. These are commonly called as catecholamines. These are rapidly secreted in response to stress of any kind and during emergency situations and are called emergency hormones or hormones of fight or flight. These hormones increase alertness, pupillary dilation, piloerection (raising of hairs), sweating, etc. Both the hormones increase the heartbeat, the strength of heart contraction and the rate of respiration. Catecholamines also stimulate the breakdown of glycogen, lipids and proteins.

B.

inversely proportional to the concentration of CO₂ in the medium

Bohr's effect is the phenomenon whereby the affinity of the respiratory pigment i.e., haemoglobin in the blood for oxygen is reduced when the level of carbon dioxide is increased. An increase in carbon dioxide concentration makes the blood more acidic which results in decrease in the efficiency of the uptake of oxygen by haemoglobin molecules. This facilitates gaseous exchange, because more oxygen is released in the tissues where the amount of carbon dioxide is rising due to metabolic activity. In its reverse, more oxygen is taken up at the lungs where the amount of carbon dioxide is low.

D.

N₂ fixation

Bacteria like Rhizobium and Frankia live free as aerobes in the soil but are unable to fix nitrogen. They develop the ability to fix nitrogen only as a symbiont when they become anaerobic. They are unable to fix nitrogen by themselves. Roots of a legume secrete chemical attractants. Bacteria collect over the root hairs and form an infection thread enclosing the bacteria. Infection thread grows along with multiplication of bacteria. Bacteria stop dividing and form irregular polyhedral structures called bacteroids. In an infected cell, bacteroids occur in groups surrounded by host membrane. The host cell develops a pinkish pigment called leghaemoglobin (Lb). It is oxygen scavenger and is related to blood pigment haemoglobin. It protects nitrogen fixing enzyme nitrogenase from oxygen.

D.

Both have segmented body

Segmentation occurs in three highly organized phyla-annelida (earthworm), arthropoda (Periplaneta) and chordates. The body is often divided both externally and internally into a number of segments (metameres) e.g., annelids. Segmentation is mostly external in arthropods and mainly internal in man and other chordates.

A.

K>Na>Fe>Cu

Potassium is a very significant body mineral, important to both cellular and electrical function. It is one of the main blood minerals called 'electrolytes' (the others are sodium and chloride), which means it carries a tiny electrical charge (potential). Potassium is the primary positive ion (cation) found within the cells, where 98 percent of the 120 grams of potassium contained in the body is found. The blood serum contains about 4-5 mg. (per 100 ml.) of the total potassium; the red blood cells contain 420 mg., which is why a red-blood-cell level is a better indication of an individual's potassium status than the commonly used serum level.

A.

Mitosis occurs after G₀ phase.

G₀ phase is the stage of inactivation of cell cycle due to non-availability of mitogens and energy rich compounds. The cells in this phase remain metabolically active and usually grow in size assuming particular shape (cell differentiation). Cell enters G₀ phase from a cell cycle checkpoint in the G₁ phase. G₁ phase checkpoint (restriction point) takes the key decision whether the cell should divide, delay division or enter resting stage. Cells then remain in G₀ phase until there is a reason for them to divide. Several biocatalysts can help a cell in G₀ phase to proceed through cell division when required.

C.

A-iii; B-i; C-ii

Alkaloids - Morphine, Codeine
Pigments- Carotenoids, Anthocyanin
Drugs- Vinblastin, Curcumin.

C.

tea

Four main types of commercial tea are generally recognized in the trade. These are black tea (China, India, Sri Lanka), green tea (China, Japan and Taiwan), oolong tea (Taiwan) and brick tea (China). Dust or fannings are left over small part of tea leaves, which are also widely used.

B.

cell organelle

The cardiac cycle consists of one heart beat or one cycle of contraction and relaxation of the cardiac muscle. The contraction phase is called the systole while the relaxation phase is called the diastole.

C.

medicinal and perennial

The given floral diagram is of liliaceae family. This family is a characteristic representative of monocot plants. Most plants of this family are good ornamentals, source of medicine, vegetables and colchicine.