The Cell Structure and Functions

Topic Content:

Cells vary a great deal in size and shape depending on their function. Nevertheless, it is possible to make a drawing to show the generalized features of a cell, though there is no such thing as a typical plant cell or animal cell.

Generally, all cells have a cell membrane which is a thin layer of the cytoplasm. Most cells have a nucleus. The main cell organelles and their function are shown below.

1. Nucleus:

Most cells contain one nucleus seen as a rounded structure enclosed in a membrane (nuclear membrane) and embedded in the cytoplasm. The nucleus contains chromosomes (made of DNA).

The nucleus is surrounded by a selectively/semi-permeable membrane that contains pores and allows for the transport of large molecules such as RNA.

Functions:

i. It controls the type and quantity of enzymes produced by the cytoplasm.
ii. The nucleus controls cell division.
iii. It controls and coordinates many activities of the cell.

2. Nucleolus:

Contained within the nucleus is a dense, membrane-less structure composed of RNA and proteins called the nucleolus .

There are tangles of chromatin and unfinished bits of ribosomes. They are prominent