Ask Away!

[nycneighbor]

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Hey everyone,

I'm sure I'm not the only one that checks SDN often, especially with regards to the MCAT. I don't know if you all would be up for this kind of thread, but let's make the best use of our visits to the MCAT forum.

Whenever you're here and reading away, pick a topic that you've recently studied or have been weak at, and make up your own MCAT style multiple choice question. We're definitely not AAMC writers, but we can try our best.

It'll make you feel a bit better about all the time you're spending away from your books, and if you can make a good question with plausible answer choices, then you'll also learn potential pitfalls that may appear on test day.

Answer the question of the person before you, and explain why it's that answer before posting your own question.

I'll start...

Myasthenia gravis, an autoimmune disorder, is caused by antibodies that block the receptors in a neuromuscular junction. What is a possible therapy for this disease?

A. Dopamine injection
B. Blockage of voltage dependent calcium channels in presynaptic neuron
C. Stimulating reuptake process of dopamine transporter
D. Anti acetylcholinesterase agents

 

[Marjan Islam]

I'll go with D. Anti cetylcholinesterase agents

At the neuromuscular junction, acetylcholine is the neurotransmitter, so I'm assuming in this disorder, the antibodies are competitively binding to the receptors, preventing acetylcholine from doing so. By adding anti acetylcholinesterase agents, we prevent the enzyme from breaking down acetylcholine, increasing acetylcholine's concentration, and thus outcompeting the antibodies for the receptor.

 

[nycneighbor]

You're right-- your question?

 

[JaggerPlate]

I'll go with D. Anti cetylcholinesterase agents

At the neuromuscular junction, acetylcholine is the neurotransmitter, so I'm assuming in this disorder, the antibodies are competitively binding to the receptors, preventing acetylcholine from doing so. By adding anti acetylcholinesterase agents, we prevent the enzyme from breaking down acetylcholine, increasing acetylcholine's concentration, and thus outcompeting the antibodies for the receptor.

Yeah, D is the only answer that works ... assuming that antibody binds competitively (which I guess you'd have to).

 

[zayka]

haven't started studying yet, buy the NMJ has nicotinic acetylcholine receptors. Acetlecholinesterase destroys ACh. Myasthenia gravis is a disease known to be caused by a decoupling of the NMJ and ACh activity, so reduced ACh activity - hence decreasing AChE activity will increase the concentration of ACh -> help myasthenia gravis?

The answers related to DA are total BS because that's completely unrelated to the NMJ. Blocking vgCa2+ channels will only cause less neurotransmitter to be released, which would also be a treatment option that would get the doctor sued.

Totally irrelevant, but I'm studying for a neuroanatomy exam, and the clinical signs of myasthenia gravis are flaccid paralysis, fasciculations, fibrillations, hyporeflexia, muscle atrophy, negative Babisnski...

BUT all you really need to know to answer this Q correctly is that the NMJ has ACh receptors.

I don't have questions - I just answer them 😉... I'll find some once I'm done the semester, otherwise they'll probably be stuff from past tests

 

[Forkit]

What a terrible idea for a thread. Anyone actually looked through a sample MCAT for the Biology section?

 

[scrubswannabe]

What a terrible idea for a thread. Anyone actually looked through a sample MCAT for the Biology section?

hahah yea i agree with forkit

the actual bio questions seem to be MUCH easier and more about extracting information from passages

that question above seems way too hard i feel

 

[zayka]

I don't think that's a hard question, but I do think that it would be better to use real Q's as opposed to made up ones.

 

[JaggerPlate]

What a terrible idea for a thread. Anyone actually looked through a sample MCAT for the Biology section?

I took an AAMC test recently with a passage based around the exact same concept with questions very similar in content and difficultly. The concept it's testing in the question is fairly clear - with minor inference - I don't think it's too crazy/off the wall.

 

[Revilla]

I think this is a wonderful idea for a thread! While it may not be exactly like MCAT Bio, every little bit of of problem solving skills (which were needed to answer the question the OP posed) will help you when it comes to the MCAT.

I don't think we should use real MCAT questions from review materials or practice tests. Some of us are taking those practice tests and using those questions will skew our results. Even using questions in EK will give us the answer before we've had a chance to read it on our own.

There are a lot of people on this forum who've taken upper level courses. Letting them make up questions and present them here can only help all of us. I don't see the harm and I actually see a great deal of benefit.

 

[0Complications]

I took an AAMC test recently with a passage based around the exact same concept with questions very similar in content and difficultly. The concept it's testing in the question is fairly clear - with minor inference - I don't think it's too crazy/off the wall.

I agree with this, but I think they would actually use the term AChE inhibitor or use it as an opportunity to also hit competitive vs noncompetitive interactions.

 

[JaggerPlate]

I agree with this, but I think they would actually use the term AChE inhibitor or use it as an opportunity to also hit competitive vs noncompetitive interactions.

Definitely.