AAMC Qpack Bio vol 2 and Chemistry

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lotus0618
Posts: 182
Joined: Sun Dec 29, 2019 5:47 pm

AAMC Qpack Bio vol 2 and Chemistry

Post by lotus0618 » Wed Jun 17, 2020 11:31 pm

AAMC Qpack Bio volume 2
1) question 37: how do you know that these cells are somatic cells?

AAMC Qpack Chemistry
1) question 70: I know this is a basic problem, but based on the solution, how am I supposed to know that I need to solve it this way. Can you please explain the logic of this problem? So that next time when I come across this type, I can reason it out.

Thank you!
NS_Tutor_Nancy
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Re: AAMC Qpack Bio vol 2 and Chemistry

Post by NS_Tutor_Nancy » Thu Jun 18, 2020 10:46 pm

Hello!

Q37: So here it is so early in development you wouldn't expect germ cells most likely. This question is mostly just trying to get at the fact that regardless of 2-cell vs 64-cell stage you will still have same number of chromosomes because you are increasing cell number through mitosis.

Q70: To go about this one, find the concentration of Na+ in each separate solution. Then, since you are combining equal volumes of the solutions together, take the average of the 2 concentrations. To find the concentration of Na+ in each solution, you need to pay attention to how much sodium is in each molecule. NaHCO3 would dissociate to give 1 Na+, so the concentration of Na+ is equal to the concentration of NaHCO3. Na2CO32 would give 2Na+ so the concentration of Na+ is double the concentration of Na2CO32.

Good luck!
lotus0618
Posts: 182
Joined: Sun Dec 29, 2019 5:47 pm

Re: AAMC Qpack Bio vol 2 and Chemistry

Post by lotus0618 » Fri Jun 19, 2020 1:51 pm

Hi! for question 37 Bio: how do you know that it's only mitosis?
NS_Tutor_Yuqi
Posts: 57
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Re: AAMC Qpack Bio vol 2 and Chemistry

Post by NS_Tutor_Yuqi » Sun Jun 21, 2020 2:13 pm

As Nancy said earlier, since the organism is only going from the 2 cell to 64 cell stages, we know that we aren't dealing with the development of germ cells. Instead, the organism is simply trying to multiply and grow in size in order to form the morula (what we call the organism that's at the 64 cell stage). Therefore, it would be mitosis and not meiosis.
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