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Ameboid Locomotion of the Cell

• Ameboid locomotion is the movement of an entire cell in relation to its surrounding.

Mechanism of Ameboid Locomotion

Moving the Cell Membrane

At rear end of the cell…

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endocytosis

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Shrinkage of cell membrane, and formation of endocytotic vesicle

↓ The vesicle is transported to the leading end of the cell

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Inserted on the cell membrane by exocytosis

↓ Cell membrane expands at leading end

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Formation of pseudopodeum

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Receptors on the cell membrane attach the cell firmly to the new area.

Moving the Cell Body

In the pseudopodium, network of actin and actin-binding proteins such as myosin is synthesized

↓ This network contracts

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Pulls the cell body towards pseudopodium

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Thus the entire cell moves

Control of Ameboid Locomotion: Chemotaxis

Chemotactic Substance

• Direction of movement is guided by chemicals called chemotactic substance.

• Its concentration is higher near its source, and it gets lower away from the source.

• The cell detects this concentration difference and decides which direction to move to.

Positive chemotaxis

• The cell moves toward the higher concentration of the chemotactic substance i.e. towards the source of chemotactic substance.

• This is more common.

Negative chemotaxis

• The cell moves away from the source.

• It's less common.

Cells Showing Ameboid Movement in the Body

• White Blood Cells: To move from blood vessels to tissue.

• Fibroblast: To move to the damaged area for repair.

• Embryonic Cells: To spread the cells developed new tissues, organs, etc.

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