AAMC CBT4 and 4R OFFICIAL Q&A

[Vihsadas]

This is the official Q&A thread for AAMC CBT4 and 4R.

Please post ONLY questions pertaining to AAMC CBT4 and 4R.
Out of respect for people who may not have completed the other exams, do not post questions or material from any other AAMC exam.

Please see this thread for the rules of order before you post.

Good luck on your MCAT!

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[minakosmas]

For #174.

If only the deterministic hypothesis is correct, undifferentiated stem cells isolated from bone marrow and grown in vitro will:

a. require the correct external signal to replicate
b. start to develop new receptors in adaptation to their new environment
c. differentiate non-randomly only when specific hormones are present
d. develop receptors in a random fashion

The answer is not in my solutions, so I need an answer and an explanation.

My reasoning is the answer is B. C and D partially support the stochastic view, and A doesn't seem to be addressed in the passage.

I do not have the answer too. But I believe that the correct answer is C. If the deterministic hypothesis is correct, not the stochastic view, then the differentiation of the stem cells is NOT RANDOMLY & OCCURS UNDER CONTROL AND INDUCTION BY SPECIFIC HORMONES (EXTERNAL SIGNAL).

Answer A is wrong because it talks about replication not differentiation. Answer B is out of the scope and nothing in the passage suggest changing the receptors (developing new ones) to adapt with the new environment. Also, answer D is wrong because it talks about random fashion which support the opposite view.

Please let me know if you agree with that reasoning or no so I learn if I am wrong.

For #174.

If only the deterministic hypothesis is correct, undifferentiated stem cells isolated from bone marrow and grown in vitro will:

a. require the correct external signal to replicate

 

[Perseverance7779311]

Hey guys, could someone please help me with this question on AAMC 4 #41
It reads, which of the following changes to the circuit will decrease the electric field between the electrodes by the greatest amount?
It says the answer is, A)Increasing the L by a factor of 2.
The description in the answer says to use E=(V-IR)/L. I understand how increasing L by a factor of 2 would decrease the electric field....but I just don't understand where V-IR came from. Im assuming they're using the V=ED equation, but i can't understand where -IR came from. Could someone please help me.

 

[Cawolf]

@Dominique8604

You are correct to use E = V/d for the solution.

The reason they list the alternative formula is for the situation where a resistor is in series with the capacitor. If the resistor is before the capacitor it will "consume" some of the EMF of the cell and make the effective voltage across the plates less (as shown by the alternative formula).

The IR is from Ohm's law where V = IR.

 

[Perseverance7779311]

@Cawolf, thank you for posting the link to the thread. whoops! lol. Thank you. I really appreciate your help!

 

[Cawolf]

@Dominique8604

Np!