This set of Cell Biology Questions & Answers for Exams focuses on “Cytoplasmic Membrane Systems – Plant Cell Vacuoles”.
1. 90% of the volume of a plant cell is occupied by the vacuole.
Explanation: Many cells of a plant are occupied by 90% of the vacuole. Most of the cell’s sugars, proteins and other biomolecules are stored temporarily in the vacuole.
2. In plant cells, by-products of the metabolic pathways are stored in _____________
Explanation: Vacuoles store many toxic compounds of the cell including by-products of metabolic pathways. Unlike animal cells, plant cells isolate the toxic by-products (by storing them in the vacuole) from the rest of the cell rather than discharging them.
3. Which of the following is a toxic by-product stored in the plant cell vacuole that is clinical importance?
b) sialic acid
Explanation: Digitalis is a toxic by-product stored in the plant cell vacuole, used to treat congestive heart failure and heart rhythm problems.
4. Tonoplast is a ___________
b) toxic compound
Explanation: Tonoplast is the membrane that bounds the vacuole. It contains many active transport system that pumps ions into the vacuole.
5. Water enters the vacuole by ____________
a) reverse osmosis
c) active diffusion
d) passive diffusion
Explanation: Due to high concentration of ions in the vacuole, water enters by osmosis. Hydrostatic pressure exerted by the vacuole provides mechanical strength to the plant cell.
6. Plant vacuoles are also sites of intracellular digestion.
Explanation: Similar to lysosomes present in the animal cells, plant cells contain vacuoles for intracellular digestion. Plant vacuoles have many of the same acid hydrolases as present in the lysosomes.
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