feature of mitochondria provides the least amount of information about their endosymbiotic origins?

Question

A.  Circular chromosome
B.  Mode of replication
C.  Independent replication
D.  Phospholipids in the membranes

Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?
 
Gather Content
· What do you already know mitochondria and endosymbiosis? How does it relate to the question?
 
Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
 
Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

D.  Phospholipids in the membranes

Clarify Question
· What is the key concept addressed by the question?
        o This question is asking you to evaluate four categories of evidence for endosymbiosis and determine which one is the weakest.
· What type of thinking is required?
        o This question is an “evaluate” question, so it is asking for you to weigh and compare the different answers to determine which one provides the poorest evidence for endosymbiosis.
 
Gather Content
· What do you already know mitochondria and endosymbiosis? How does it relate to the question?
        o Mitochondria have many traits that are similar to bacteria. What are they? Some of them involve cell processes, such as replication, while others are characteristics of the cell itself.
        o What happens to mitochondria during mitosis?
 
Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o Go through each possible answer and write down how it shows that mitochondria evolved by endosymbiosis. Some things, like DNA and cellular processes, are less likely to evolve multiple times. If mitochondria and bacteria share these traits, they are most likely due to homology instead of convergent evolution.
 
Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        o This question asked you to determine which of the options provided the weakest evidence for endosymbiosis.
        o If you got the correct answer, great job!
        o If you got an incorrect answer, where did you get stuck?
            · Did you have a hard time judging the options? The textbook highlights the best evidence for endosymbiosis, and it does not mention phospholipids. It is true that the phospholipids on the inner membrane of mitochondria are similar to bacteria, but phospholipids easily change. Things like a circular chromosome, binary fission, and independent replication do not change easily, so they are most likely a homology with present-day bacteria.