Cell structure and function (8th class portions)

BY-VIDHI.K.SHAH OF-VIII

VARIATION IN NUMBER:Organisms are of 2 types* Unicellular organisms*Multicellular organismsVARIATION IN SHAPEOrganisms are of 3 types*Nerve cells*Muscle cells*Skin cells

VARIATION IN SIZE:*Here, organisms can vary from a Micrometreto a few Centimeter.

Cell consists of one main part which is known as the ‘Brain of the cell’. Cell membrane ,cytoplasm ,nucleus.

CELL MEMBRANE: It acts as the outer covering of the cell. Which has a porous membrane to it. As the plasma membrane.

CYTOPLASM: Many organelles are present in the cytoplasm. It is a jelly like fluid.

NUCLEUS: It is known as the ‘brain of the cell’. It is surrounded by the nuclear membrane. It also contains the chromosomes, that carry genes, that are transferred during cell division.

Golgi apparatus -> are small tubes, that are responsible for the secretion of chemical substance.

Vacuole -> they store excess water, useful minerals.

Lysosome -> they contain enzymes, at times of emergency they burst and destroy the cell, They are also called as ‘The suicidal bag of the cell’.

Endoplasmic reticulum -> They

help in the transport and storage of cell

products. Ribosome -> They

are granulated substances

present in the cytoplasm.

Mitocondria -> They are tiny rod-shaped

bodies is know as ‘The power house of the cell’. They act as sites of energy.

Centrosome -> They are present only in animal cells, their function is to initiate and regulate cell division.

Plastids -> they are only present in the plant cell, there are of three types of plastids.1) chromoplast2) chloroplast3)leucoplast

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