Q21

[sr]

The correct answer is apparently D, but D refers to "serotoninlike drugs". I did not select this answer because serotoninlike drugs is simply the wrong classification of the drugs in the passage. The drugs they were referring to are drugs that facilitate or block serotonin. The drugs themselves are not like serotonin, they merely affect serotonin. Serotoninlike drugs would mean drugs that are similar to serotonin (almost like taking fake serotonin in pill form) but these drugs are completely different than serotonin. For example a drug that affects the amount of tryptophan absorbed is NOTHING like serotonin itself, it merely is a chemical that causes a chain reaction which results in increasing/decreasing serotonin levels.

[ManhattanPrepLSAT1]

The drugs they were referring to are drugs that facilitate or block serotonin.

The question at the beginning of the passage sets out the main point. Which is that serotonin, one of a class of chemical mediators that may be released from a presynaptic neuron, is part of the explanation for how the brain knows when carbohydrates have been or should be consumed?

I think this sounds like it's perfectly stated in answer choice (D), but let me know if you see otherwise.

The drugs themselves are not like serotonin, they merely affect serotonin.

I think you're look at the drugs given to rats mentioned in the 3rd paragraph, but that's not the drug that's mentioned in answer choice (D). Instead in answer choice (D) the are referring to the serotoninlike drug mentioned in line 45.

Hope that helps!

[judy.kang020]

Can someone please explain why (A) is incorrect? Thank you

[Mab6q]

A is incorrect if you remembered that the serotonin does not actually reside in the blood. It is the tryptophan that is in the blood, which later produces the S once it is transported.

D gave me some troubles but A is clearly incorrect for that reason.

[uhdang]

Just wanted to share my thoughts on why A) is incorrect. Considering the first paragraph and the last paragraph and the rat experiment talks decent portion about serotonin-inducing drugs, I thought that the main idea should mention something about the drugs. Thus, between A) and B), A) omits the part about the drugs while B) ONLY talks about the drugs. Those are the reasons why I thought they were incorrect.

While I'm at this, let's look at other answer choices.

For C), this is largely concentrated on only third and the half of fourth paragraph where it talks about rat experiment and similar demonstration with drugs to human. Forgets to include what the second paragraph was focused on: How Carb intake affects serotonin secretion.

D) does exactly what I pointed out above by sort of combining A) and B), and covers serotonin's function as well as serotonin-inducing drugs. This is it. Correct

E) This is concentrated only on the second paragraph.

[vstoever]

Also to add to A, it is not the body's need for carbs that is explained, it's the body's thinking it needs or desire for carbs. The body might be confused and think it needs carbs, like the rats, when really it already had enough