Question

Which of the following is NOT offered as evidence in support of the endosymbiotic theory, the belief that a eukaryotic cell has evolved as a "committee" of prokaryotic cells?

A. Mitochondria and chloroplasts are similar in size and structure to some species of bacteria.
B. The ribosomes of chloroplasts and mitochondria are similar to bacteria.
C. Mitochondria and chloroplasts can actively break away from eukaryotic cells and live on their own.
D. Mitochondria and chloroplasts have their own DNA coding separate from the eukaryotic nucleus.
E. All of the choices offer support of the endosymbiotic theory.

Answer 1

The incorrect option for evidence supporting the endosymbiotic theory is C, as mitochondria and chloroplasts cannot live independently outside the eukaryotic cell. The other options are valid pieces of evidence, including similarities in size, structure, ribosomes, and DNA to bacteria.

Step-by-step explanation:

The option that is NOT offered as evidence in support of the endosymbiotic theory is C. Mitochondria and chloroplasts can actively break away from eukaryotic cells and live on their own. This statement is incorrect as mitochondria and chloroplasts, while similar in many ways to prokaryotes, cannot live on their own outside the eukaryotic cell. The other options, such as the similarity in size and structure to certain bacteria (A), the similarity of ribosomes (B), and having their own DNA coding separate from the nucleus (D), are all valid pieces of evidence supporting the endosymbiotic theory. These organelles are believed to have originated from a symbiotic relationship between early eukaryotic cells and prokaryotic organisms, where the latter were ingested but not digested, eventually becoming functional parts of the cell. The theory is supported by the fact that mitochondria and chloroplasts reproduce through a process that resembles bacterial binary fission, and phylogenetic analysis shows their DNA is closely related to bacterial DNA.