Question

Some genes in plant cell nuclei are most similar to genes from cyanobacteria. This is explained by:

a)horizontal transfer of endosymbiont genes to the nucleus.

b)plants and cyanobacteria having a common ancestor.

c)horizontal gene transfer from non-photosynthetic bacteria to plant nuclei.

Answer 1

Option A

Some of the genes present in plant cell are similar to that of cyanobacteria. This is explained on the basis of endosymbiotic theory. According to this theory, prokaryotic bacteria capable of performing photosynthesis was eaten up by a Eukaryotic organism. The to started living together in a symbiotic Association. With course of time, some of the genes from the photosynthetic bacteria was transferred to the Eukaryotic organism. This lead to the development of chloroplast in plants.

The origin of Mitochondria in eukaryotes is also explained on the basis of endosymbiotic theory. A prokaryotic organism capable of performing cellular respiration in the presence of oxygen was eaten up by some other Eukaryotic organism and the two started living together in symbiotic Association. With time, the prokaryotic bacteria involved into mitochondria because of exchange of genes between the two organisms.

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