Question

Which of the following statements about the endosymbiotic theory is false?

1) Eukaryotic cells engulfed the ancestral bacteria from which mitochondria and chloroplasts are derived, and the two entities formed a symbiotic relationship.
2) The entire genome of the ancestral bacteria has been preserved in present-day mitochondria and chloroplasts.
3) Mitochondria and chloroplasts arose independently from free-living bacteria.
4) The ancestral bacteria, from which mitochondria and chloroplasts are derived, were capable of photosynthesis and aerobic respiration.

Answer 1

The false statement is that the ancestral bacteria, from which mitochondria and chloroplasts are derived, were capable of photosynthesis and aerobic respiration.

Step-by-step explanation:

The false statement about the endosymbiotic theory is statement 4: The ancestral bacteria, from which mitochondria and chloroplasts are derived, were capable of photosynthesis and aerobic respiration.

The endosymbiotic theory proposes that mitochondria and chloroplasts were once free-living bacteria that were engulfed by ancestral eukaryotic cells and formed a symbiotic relationship. However, the ancestral bacteria were not capable of both photosynthesis and aerobic respiration, as stated in option 4. Mitochondria were derived from aerobic bacteria capable of aerobic respiration, while chloroplasts were derived from photosynthetic bacteria.

Besides option 4, the other statements are true. The endosymbiotic theory is supported by genetic evidence, such as the similarity between mitochondria and bacteria in DNA sequence, chromosome structure, and ribosomal structure. Additionally, endosymbiotic relationships between bacteria and eukaryotic cells can still be observed, such as in the gut bacteria of certain insects and in photosynthetic organelles in protists.