Which one of the following statements about 'vacuoles' is not correct?
- A.In plants, there is a large central vacuole that may occupy 90% of total cell volume.
- B.In plant cells, vacuoles provide turgidity and rigidity.
- C.In Amoeba, vacuoles have role in nutrition.
- D.Vacuoles are absent in animal cells.
Correct answer
Explanation
The correct answer is D, Vacuoles are absent in animal cells. Animal cells do have vacuoles; they are only small and often temporary, so the statement is wrong.
A vacuole is a membrane-bound sac filled with cell sap: water, salts, sugars and waste. Its membrane in plant cells is called the tonoplast. In mature plant cells a single central vacuole can fill up to about 90 per cent of the cell, pressing the cytoplasm against the wall. Animal cells carry several small vacuoles for storage, digestion and removing wastes, and single-celled organisms use them to take in food and expel excess water.
A is correct: the central vacuole of a mature plant cell may take up as much as 90 per cent of its volume.
B is correct: water pressure in the vacuole keeps plant cells turgid and gives the plant rigidity.
C is correct: Amoeba forms food vacuoles around its prey to digest it, and a contractile vacuole removes extra water.
Exam tip: plant cells, one large vacuole; animal cells, many small vacuoles; Amoeba, food and contractile vacuoles.
Practice Questions
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- B.Mitochondrion
- C.Lysosome
- D.Endoplasmic reticulum
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- B.Onion, garlic, carrot
- C.Potato, onion, garlic
- D.Potato, garlic, turnip
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- A.0.5 s
- B.1 s
- C.1.5 s
- D.2 s
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- A.equal to its weight.
- B.less than its weight.
- C.greater than its weight.
- D.zero.
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- A.Forefront brain, Standard brain and Hind brain
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- C.Fore brain, Mid brain and Hind brain
- D.Precursor brain, Mean brain and Hind brain
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