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Molecular Genetics


Big MCAT things here, you'll be heavily tested on molecular genetics. So central dogma of molecular genetics simply this. You have DNA and that gets converted to RNA. And that can get converted into proteins. And the process whereby DNA gets converted into RNA is, transcription. And the process whereby RNA gets converted into proteins, is translation.

And then DNA also often needs to make more of itself, so DNA gets converted back into DNA, and this process is called replication. So you're not gonna have a question that asks you what the social dogma is, but this is setting up what we need to understand about molecular genetics, okay? So DNA is comprised of few things, specifically. One, you have a pentose sugar.

The five carbon sugar. And in the case of DNA, the sugar is deoxyribose, and in the case of RNA, the sugar is ribose. So second component of DNA is base, and the final component is phosphate curve. And I should take an opportunity I mentioned here, of all the MCATs subjects, biology is the one that students have the strongest.

And so if you feel like you know this stuff, go ahead and as I've mentioned, see if you can write out these things before I do, and test yourself, and see if you're really do know these things, okay? Now, what can your bases be? Many of you probably know you have either pyrimidine or purines bases, and the classic way to remember it is you CUT the pie, or you're pure as gold, okay?

So pyrimidine bases are cytosine, uracil, and thymine. Purine bases are adenine and guanine, okay? G and C will bind. And A will bind with T or U. And in DNA, it will be, T a thymine and RNA, it would be the uracil. And G and C, they form three hydrogen bonds between the two of them.

A and T or A and U form two hydrogen bonds between the two of them, okay? And this is an opportunity for MCAT test makers to ask you one of their favorite questions that's shown up on several recent MCATs. Which is the fact that the more G to C content you have, the more hydrogen bonds you have. And thus, the higher melting of annealing temperatures that you are now having.

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