Question

3a. Describe how genetic evidence using phylogenetic trees supports the endosymbiosis theory that
mitochondria and chloroplasts evolved from bacteria.
3b. It has been observed that certain antibiotics that inhibit the bacterial ribosome can also adversely affect
mitochondrial activity. How would you explain this observation.

Answer both questions thoroughly and completely

Answer 1

3a). The endosymbiotic theory supports the statement that the mitochondria and chloroplasts are derived from the bacteria (prokaryotes). The mitochondria, chloroplasts, and bacteria share the similarities in DNA and ribosomes, both share the double membrane structure. The mitochondria and chloroplasts multiply similar to the binary fission of bacteria. According to the endosymbiotic theory, the bacterial cell was engulfed by an ancestral cell and converted it into a particular organelle.

The genetic evidence of endosymbiotic theory: During 1970’s, scientists compared the genes of chloroplast and nuclei of the algae, and found the similarities and found out that the cyanobacterial DNA was turned out as chloroplast DNA. They also found that the mitochondrial DNA has some resemblance with the DNA of bacteria causing typhus, and several other symbiotic events were related to the evolution of mitochondrial and chloroplast DNA.

3b). Due to the similarity in the eukaryotic mitochondrial DNA and that of the bacterial DNA, antibiotics that inhibit bacterial ribosome can also adversely affect the mitochondrial activity.