Question

32. Chloroplasts maintained the essential genes ________ from the ancestral endosymbiont from which they evolved. a. NADH dehydrogenase, cytochrome oxidase, and ATP synthetase

b. pyruvate dehydrogenase, citrate synthase, and fumarase

c. hexokinase, phosphoglucose isomerase, and phosphofructokinase

d. rRNA, tRNA, and rubisco

e. catalase, superoxide dismutase, and peroxidase

Answer 1

OPTION D

Chloroplast is a double membrane bound organelle which is exclusively found in eukaryotic cell. It is also called as the kitchen of the cell because it is the site of photosynthesis.

According to endosymbiotic theory, chloroplast have been evolved from a prokaryotic ancestor which was capable of undergoing oxygenic photosynthesis. During the process, a prokaryotic cell was eaten up by a eukaryotic cell. Both of them started living together in a symbiotic association.

With the course of evolution, some of the genes were exchanged between the two. The genes which are now present in chloroplast was actually the genome of the ancestor of chloroplast. Gene encoding for rubisco enzyme and some of the ribosomal RNA and transfer RNA are present in the chloroplast itself. Rest all the other proteins of chloroplast are encoded by nucleus.

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