Question

British scientist John Allen states that cells containing chloroplasts and mitochondria are complex, creating unique genes and proteins. Allen believes that cells containing chloroplasts and mitochondria came to exist because organelles such as a mitochondria engaged in reactions that benefited early simple cells. b chloroplasts engaged in reactions that temporarily benefited early simple cells and recent complex cells. c mitochondria engaged in reactions that benefited simple cells and recent complex cells on a single occasion. d chloroplasts engaged in reactions that benefited recent complex cells.

Answer 1

John Allen’s perspective on the evolution of cells with chloroplasts and mitochondria is closely related to the endosymbiotic theory. According to this theory, complex cells (eukaryotes) arose from a symbiotic relationship between early simple cells (prokaryotes) and certain organelles that became incorporated into them.

Based on your description, it seems that Allen believes that both chloroplasts and mitochondria played a significant role in the evolution of more complex cells through beneficial interactions. The best option that reflects this idea is:

a) mitochondria engaged in reactions that benefited simple cells and recent complex cells.

This suggests that mitochondria provided benefits to both early simple cells and have continued to provide advantages to more complex cells throughout evolution, aligning with the endosymbiotic theory.