Q. 6

[apmehta]

I do not understand fully why the answer to this is B. Determination when the question asks about the the blastomeres differentiating into germ cells.

Wouldn't the point when blastomeres become determined to being germ cell come before the blastomeres actually start to differentiate into germ cells?

[admin]

Tough question. You should only expect a couple of these types of "tricky" questions per section. However, that should not affect your overall score.

I can't think of any great analogies right now but consider this: how do you get to your local McDonald's?!

Drive to the corner, turn left, speed up, merge on the highway, exit 19, slow down: it's on your left.

Differentiation is the slowing down, "it's on your left" part. Determination is driving. It's not a perfect analogy but determination represents most of the work to get there. The blastomere may have the same morphology but so much of the internal machinery had to undergo significant changes to become committed to becoming a particular type of cell.

Also, notice the word "mechanism". How is it possible that a cell differentiates? The car slowed down only because you were first driving then driving fast which provide the tools and condition to slow down.

I hope that helps.

[stoneprod7112]

My problem with this question and answer is that there is seemingly no reason given for why the answer could not be induction. Especially since in section 14.5.1 of the gold standard the definition for induction is "the general mechanism by which cells differentiate"

So why is the answer here determinism and not induction?

[GraemeMatt8033]

Remember for the MCAT alot of the answers come from the passage.
In the second paragraph, second sentence it says:
"Early in the development of all animals, certain cells undergo determination producing primordial germ cells."

[dnpgr16513]

Can you please describe the difference between all the answers? Like describe what each choice is. I tried to research it but I had no luck. Are differentiation and specialization synonymous?

Thanks.

[admin]

Please refer to the Gold Standard MCAT book, like it says on the online CBT to chapter 14.5.1, you will find your answer there.