#1.) Knowing what you
do about sexual reproduction in humans, can you sensibly reason that
mitochondrial DNA from the offspring is maternal only?
A. No. Since each of the gametes is haploid, exactly
half of the contribution comes from the male and half comes from the female so
it does not make sense for an organism’s mitochondrial DNA to be maternal only.
B. No. It is a well known fact that sperm contain
many mitochondria to help in the journey to reach the egg. It would be more sensible to assume that the
mitochondrial DNA from the offspring is paternal only.
C. Yes. The egg is produced fully prepared and
capable of providing everything needed for the developing zygote, including all
organelles and a food store, and only requires a male contribution of DNA.
D. Yes. Since the egg is so much larger in physical size relative to the sperm and fewer are produced every month relative to sperm, it would make sense that the egg contained the organelles for the developing zygote and eventual fetus.
E. I don’t know
Evolution:
With this question, I was hoping to elicit some common
misconceptions. From what I know about
teaching this material, students do not know a lot about sexual reproduction,
and the little they do know is very superficial. Asking them a “why” question laced with
plausible distractors is more difficult and would hopefully result in great discussion.
This question was pretty much the same from the beginning until now. The only thing I changed was the amount of answer on choice D. Originally, choice D only had the word "yes" as an answer. I added in information to help make the question more difficult to solve, as now choice D is a more plausible alternative. However, choice C is the most correct.
I like this question and I am looking for clarification, would you consider D a correct answer? you said C is more correct, but if it is "more correct" does that mean D is still correct?
ReplyDeleteI understand you are trying to create some confusion and trick them up but if I were a student I would argue with you for the extra over achiever point! haha