This pond is beside a school sports field, and Fig. 1 shows a freshwater amoeba viewed through a microscope. Rainwater has made the pond water dilute compar...
Question 1 Report
This pond is beside a school sports field, and Fig. 1 shows a freshwater amoeba viewed through a microscope. Rainwater has made the pond water dilute compared with the amoeba's cell contents. Water continually enters the cell. A contractile vacuole fills and then empties at regular intervals.
(a) Identify the process by which water enters the amoeba. [1]
(b) Explain why water enters the cell from the pond. [2]
(c) Use the figure to explain the role of the contractile vacuole. [2]
Answer Details
(a) Osmosis [1] (b) Pond water has a higher water concentration / is more dilute than the cell contents [1]; water moves through the partially permeable cell membrane into the cell [1] (c) It collects excess water [1]; it contracts to expel water and stops the cell bursting [1]
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