Write short notes on the following.
(a) Cytoplasm
(b) Nucleus of a cell
Answers
(a) Cytoplasm:
- The cytoplasm is a fluid that contains all the cell organelles such as the Mitochondria, Ribosomes, Golgi bodies, etc. It is present between the nucleus and the plasma membrane. It helps in the exchange of materials between cell organelles. It is made up of eighty percent water and is usually clear and colourless.
(b) The nucleus of a cell:
- The Nucleus is a double-membrane bound cell organelle present in eukaryotic cells. It contains the DNA, the genetic material. It is the command centre of the cell and is spherical in shape.
Explanation:
(a) Cytoplasm: It is the semi-fluid part of the cell whose main constituent is water and it is the site for a maximum reaction. It is surrounded by a cell membrane. Various cell organelles like mitochondria, ribosomes, Golgi apparatus, endoplasmic reticulum etc. are suspended in it. The cytoplasm is always in the flowing state called cytoplasmic streaming or cyclosis. This phenomenon is absent in prokaryotic cells and present in a eukaryotic cell.
(b)Nucleus of a cell: It is the dense structure present in the cell, it also acts as the information centre of the cell. It is surrounded by a nuclear membrane. It contains chromosomes that contain genetic material, i.e. DNA which is transferred from one generation to another generation. Its number can vary from one to many per cell.
For multinucleate condition, there are two kinds of cell: