What is the evidence that the ancient mitochondrial and ...

Question

What is the evidence that the ancient mitochondrial and chloroplast endosymbionts are related to the alphaproteobacteria and cyanobacteria, respectively?

Accepted Answer

Welcome back. Here's our next question. Which of the following lines of evidence supports the theory that mitochondria and chloroplasts evolved from ancient endo symbiotic processes. So as we can recall from our content, videos, there is the theory that mitochondria and chloroplast evolved because essentially they used to be separate pro caros and they formed an endo symbiotic relationship with early u carry out and now they can no longer exist independently. But we have various forms of evidence that indicate that this was how you carry outs originated by having this relationship with mitochondria and chloroplasts. So let's look through our answer choices. Noticing that choice D is all of the above. So we may have more than one correct answer. So let's keep that in mind as we go through choice. A says, antibiotic sensitivity. Well, this is evidence in favor of this theory because some antibiotics that target bacterial ribosomes are also effective against chloroplast and mitochondria. And here for the sake of space, I'm just writing C and M instead of chloroplast, mitochondria. So we think of antibiotics as things just to attack bacteria. But these specific types of antibiotics also work against chloroplast and mitochondria indicating there's enough similarity between them that they have this resemblance to those pro caros. So I'm not going to select this as our answer because again, I do have that all of the above option. So I'm just going to make a little dot To mark that this is a correct answer. Choice. B says genome structure. Well, this is also evidence in favor of this theory, chloroplast, mitochondria have circular genomes and this of course is similar to the circular uh DNA that you see in pro Caros. In addition, they have some shared genes for some metabolic pathways that are seen in modern alpha proo bacteria and cyanobacteria. So they have some shared genes with modern bacteria suggesting a shared common ancestor. So we're going to mark B as a correct answer. Now, at this point, if I were on a test and I were hurrying through, I would go ahead and select joy. D all of the above is my answer because I've already got more than one correct answer. But here we're going to be thorough in the interest of explaining everything. So we will look at choice C even if we might skip it on a test. Choice C says replication. And as you might expect, yes, this is also evidence in favor of the theory, um Chloroplast and mitochondria replicate by replicating their circular DNA and then splitting the cell similar to the way bacteria replicate as opposed to you carry outs which make the mitotic spindle and then have the partitioning of all of their chromosomes. So they replicate loro the mitochondria replicate in a similar fashion. Two bacteria versus you carry outs. So which of the following lines of evidence supports the theory that mitochondria chloroplasts evolved from ancient endosymbiont processes. And the answer is choice d all of the above. See you in the next video.

What is the evidence that the ancient mitochondrial and chloroplast endosymbionts are related to the alphaproteobacteria and cyanobacteria, respectively?

Key Concepts

Endosymbiotic Theory

Mitochondrial and Chloroplast DNA

Phylogenetic Analysis

Watch next