3. Write short notes on the following.
(a) Cytoplasm
(b) Nucleus of a cell
Answers
Answer: cytoplasm : cytoplasm is the part of the cell which is inside the cell membrane and outside the nucleus .
(1) It is a semi - liquid substance .
(2) Many chemical reactions catalyzed by enzymes occur in it .
(3) It contains several organelles,each concerned with a specific function.
(4) The part of the cytoplasm other than the organelles ( mitochondria ,etc .) is called cytosol ,which constitutes mainly the liquid medium .
Nucleus : Nucleus is the large spherical body lying nearly in the centre of the cytoplasm.
(1) It is surrounded by a double layered nuclear membrane with nuclear pores.
(2) The ground substance of the nucleus is a semi - solid substance ( nucleoplasm ) containing one or more round shaped nucleoli ( sing .nucleolus )
(3) The nucleoplasm contains a network of dark coloured fibres called chromatin fibres .These chromatin fibres condense into short thick chromosomes during cell division .
Explanation: