Question

Which of the following experimental results does NOT support the idea that

mitochondria arose by "endosymbiosis".

a. Mitochondrial DNA forms a "satellite" when centrifuged on a density gradient.
b. Many mitochondrial proteins are coded by cellular nuclear DNA.
c. Some mitochondrial proteins are NOT coded by cellular nuclear DNA.
d. Mitochondria have a double membrane structure
e. Mitochondria have ribosomes that are different from the cell’s ribosomes.

Answer 1

c. some mitochondrial proteins are not coded by cellular nuclear DNA

Step-by-step explanation:

Symbiosis is a relation between two different species and they both get to benefit from each other. Endosymbiosis has occurred inside the host. Here one organism lives inside other like mitochondria and chloroplast are present in the animal, plants.

When the mitochondrial DNA undergoes density gradient centrifugation, the satellites are separated. The density of the satellite is more so it is detached from DNA.

As mitochondria have their DNA it has its ribosome to synthesis proteins. But most of the mitochondrial proteins are present in the cell cytoplasm and nucleus. So mitochondrial proteins are coded by cell nucleus.

Mitochondria is a double membrane structure and they are present in the cell by the endosymbiosis process. They more resemble bacteria. The mitochondrial protein is transmitted by the woman, not both parents. It is passed by single lineages.

Answer 2

b. Many mitochondrial proteins are coded by cellular nuclear DNA.

Step-by-step explanation:

According to the concept of endosymbiosis, eukaryotic organelles such as mitochondria and chloroplasts arose from symbiotic relationships between larger cells and smaller prokaryotes. These smaller prokaryotes were incorporated and lived within them. According to this concept, mitochondria originated when a larger cell engulfed an aerobic bacteria (most probably the purple bacteria) that lived in it. However, some of the proteins of the mitochondria are encoded by nuclear chromosomes. This dependence of mitochondria on nuclear DNA does not support the concept of endosymbiosis.