Functions of cell structures:
The cell membrane retains the cells contents in place. In addition, gases diffuse in and out through the cell membrane.

The nucleus is the control centre of the cell.

Food vacuoles secrete acids to kill prey. They then produce enzymes to digest the prey. Digested material is absorbed from the food vacuole into the cytoplasm.

The pseudopodia extend in the direction the amoeba wants to move. The cytoplasm (especially the endoplasm) moves or flows into the pseudopodia causing the cell to move. The pseudopodia are aslo used to surround (engulf) its prey.

Amoeba live in fresh water. This means its cytoplasm is more concentrated than its external environment. As a result, water enters the amoeba by osmosis.

The contractile vacuole collects water that enters the amoeba. It then expands, touches the cell membrane, and bursts to expel the water. It is said to be responsible for osmoregulation. Without it, amoeba waould expand and burst.

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Leaving Certificate Biology (Protista (Amoeba)) Notiz am Protista (Amoeba), erstellt von eimearkelly3 am 21/07/2013.

Protista (Amoeba)