Ch.22 - Protista(Amoeba) Flashcards
Draw a diagram of the structure of amoeba.
What can be a habitat for amoeba?
They live at the bottom of shallow freshwater ponds and streams. Some live in sea water.
What is the function of amoeba’s cell membrane and nucleus?
The nucleus controls the cell. The cell membrane retains the cell contents and allows for gas exchange.
What is the cytoplasm of an amoeba made of?
The outer cytoplasm is the ectoplasm. The inner cytoplasm is the endoplasm and its grainy due to the presence of food vacuoles and waste materials.
What is the function of food vacuoles?
Food vacuoles secrete acids and enzymes which kill and digest prey.
What is the pseudopodia?
The pseudopodia extends in the direction the amoeba wishes to move. The cytoplasm moves into the pseudopodia causing it to move. The pseudopodia are also used to engulf prey.
What is the difference between amoeba that live in freshwater, against ones in seawater?
Saltwater amoebas do not need a contractile vacuole. Water enters and leaves the cytoplasm at the same rate through the cytoplasm.
Freshwater amoeba require a contractile vacuole. Because the cytoplasm is more concentrated than its surroundings, water enters the amoeba by osmosis. The contractile vacuole collects this water, expands, touches the cell membrane and bursts to expel the water.
The contractile vacuole is responsible for osmoregulation, without it it would burst and die.
Draw a diagram of the function of a contractile vacuole in an amoeba.
