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Tissues
Explain the structure of nucleus?
Nucleus. It is the control centre of the cell. It is covered by an double layered envelope called the nuclear membrane . There are numerous pores in the nuclear membrane for the transfer of materials. It consists of a dense region called nucleolus. The nucleus has chromatin which forms the chromosomes during cell division. Chromosomes consists of DNA and protein. The genes are functional unit of DNA which are responsible for the hereditary characters of an organism. 
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How does an Amoeba obtain its food?
What is osmosis?
Carry out the following osmosis experiment:
Take four peeled potato halves and hollow each one out to make potato cups. One of these potato cups should be made from a boiled potato. Put each potato cup in a trough containing water. Now,
(a) keep cup A empty
(b) put one teaspoon sugar in cup B
(c) put one teaspoon salt in cup C
(d) put one teaspoon sugar in boiled potato cup D.
Keep this setup for two hours. Then observe the four potato cups and answer the following :
(i) Explain why water gathers in the hollowed portion of B and C?
(ii) Why is potato A necessary for this experiment?
(iii) Explain why water does not gather in the hollowed out portions of A and D.
By which instrument you can see internal structure of onion peel cell?
Do different organisms have different types of basic building units ? Briefly explain.
To what the shape and size of cells are related to?
What constitute the basic building block of the cell?
Can you find out more names of some of the unicellular organisms and fungi, other than given in your book?
Name two single celled animals.
Draw diagram of onion peel as it is seen through microscope.
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