Paper 2 · June 2023 · Cells and Tissues
Fig. 1.1 shows a palisade cell. Name the process that takes place in the many oval bodies, marked with internal stripes, that lie in its cytoplasm.
APhotosynthesis, since these bodies hold the chlorophyll that traps light energy and uses it to make sugar.
BProtein synthesis, since these bodies carry the ribosomes on which amino acids are joined into long chains.
CAerobic respiration, since these bodies carry a folded inner membrane holding the enzymes that release energy from glucose.
DOsmosis, since these bodies draw water in from the cell sap and so keep the whole cell firm and turgid.
Explanation
The striped oval bodies drawn through the cytoplasm of a palisade cell are chloroplasts. Their internal stacks of membranes carry chlorophyll, which absorbs light energy and uses it to combine carbon dioxide with hydrogen from water to make sugar. A palisade cell is packed with them because it lies just under the upper surface of the leaf, where the light is strongest.
Derived from ZIMSEC Biology 4025/2, June 2023, Q1(a)(i)