Page 11 - 11-Bio-4 The Cell

4. The Cell eLearn.Punjab

Cell wall is very important. It provides a definite shape to the cell and keeps it rigid. It does not act
as a barrier to the materials passing through it.

Animation 4.2: Cell Wall
Source and Credit: gifsoup

Cytoplasm

The living contents of the eukaryotic cell are divided into nucleus and the cytoplasm, the two
collectively form protoplasm. Cytoplasm consists of an aqueous ground substance containing a
variety of cell organelles and other inclusions such as insoluble wastes and storage products. The
soluble part of the cytoplasm is called cytosol. It forms the ground substance of the cytoplasm.
Chemically it is about 90% water. It forms a solution containing all the fundamental molecules of
life. In the cytosol, small molecules and ions may form true solutions, and some large molecules
form colloidal solutions. Colloidal solution may be a sol (non-viscous) or a gel (viscous). Peripheral
parts of the cell are often like a gel.

The most important function of the cytoplasm is to act as a store house of vital chemicals. It is also
a site for certain metabolic processes such as glycolysis.

In living cells the cytoplasm contains several cell organelles such as endoplasmic reticulum,
mitochondria, Golgi complex, nucleus, plastids, ribosomes, lysosomes and centriole. The free
floating cell organelles e.g. mitochondria move about in cytoplasm due to cytoplasmic streaming
movements. This is an active mass movement of cytoplasm.

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