A molecular bio question from EK 3g

[silkworm]

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This is #143

Basically,

The explanation says: IGF-1 is structurally similar to insulin. Since structurally similar molecules often share receptors, it can be assumed IGF-1 can bind to insulin receptors.

Is this really a safe assumption? I mean, some enantiomers that's almost identical to each other can't fit into each other's receptors.

 

[bella_dottoressa]

Yeah I got this one wrong too I think. I found that on a couple EK bio q's you had to sort of make a wide assumption in order to answer correctly...I don't think the real thing would have a question like that.

 

[ExplodingBoy]

thats the answer given in the book? From everything i've learned, the active site that is going to attach to the receptor has to be an exact copy, because receptors are sooo specific. I would never make that assumption unless there was some solid proof that that specific pair of proteins can share the same receptor.

But then again, I don't write convoluted MCAT questions with 'most right' answers. =P

 

[ASDIC]

IGF-1 stands for Insulin like Growth Factor. From what I have learned in Endocrinology, IGF binds to insulin receptors. Remember Growth hormone has insulin like activity because GH causes the release of IGF-1 from the liver and the IGF then performs insulin actions.

 

[silkworm]

Thanks for the replies. What ASDIC said makes sense now. But the EK explanation logic still seems unsound.

 

[dave613]

Thanks for the replies. What ASDIC said makes sense now. But the EK explanation logic still seems unsound.

Yeah, I kind of agree. What EK says is definitely sketchy according to what you're saying.