Name the phenomenon which helps fresh water unicellular organisms (e.g. Amoeba) continuously gain water in their bodies. Also, name the mechanisms by which these organisms throw out excess of water from their bodies.

(b) Give at least two examples in plants where similar phenomenon in used to gain water.

Why does the skin of your fingers shrink when you wash clothes for a long time?

How are chromatin, chromatid and chromosome related to each other.

What is the gene? Give its functions.

Medical science took a giant step forward when it declared its capability to store stem cells. Stem cells can be used later on to treat certain diseases if need arises. Along with many Western countries. India also has the facility for storage of stem cell and for use of the same for therapy. Scientists’ are trying their best to maximize the benefit from storage of stem cells.

(i) What is the main source of stem cells?

(ii) What are the diseases that can be treated by storing stem cells?

(iii) What value is shown by the scientists?

Which functions are performed by cell wall in plant cells?

Which structure of animal cell forms the asters of spindle?

Name two factors on which shape of the cell depends.

What is endosmosis?

Plasma membrane is permeable to water. How does a cell show endosmosis or exosmosis?