tRNA....codon and anti-codon

[sps27]

The tRNA molecule has an anti-codon binding site. So how does a tRNA molecule know which protein to bind to since the codon and anti-codon both map to a specific protein. For ex., if mRNA has codon AAA which maps to Lys -- the anti-codon UUU on tRNA maps to Phe. The mRNA codon is expecting a Lys but the tRNA anti-codon has a UUU i.e., Phe in it. So how will a tRNA with amino acid Lys latch on to that mRNA codon? Does this make sense? Or have I understood it wrong?

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[icedragon]

I think you may be confused on what the codon chart is saying.

Let's start with the start sequence 5'-AUG-3' which is on the mRNA. The tRNA carrying methionine will pair up its anticodon 3'-UAC-5' to the 5'-AUG-3' mRNA. Does that clear things up?

 

[sps27]

I think you may be confused on what the codon chart is saying.

Let's start with the start sequence 5'-AUG-3' which is on the mRNA. The tRNA carrying methionine will pair up its anticodon 3'-UAC-5' to the 5'-AUG-3' mRNA. Does that clear things up?

Thanks for your response. So taking your example, if the mRNA is AUG then its anti-codon is UAC. So there must be a tRNA with UAC. Well how does that tRNA with UAC know that it needs to bind to Methionine? UAC actually translates to Tyr as per the table. So something in tRNA with UAC knows that it needs to bind to Methionine and not Tyrosine. Sorry if I have confused you more with this.

 

[icedragon]

All the codons in the table refer to the mRNA and what amino acid they correspond to, not the tRNA anticodon.

edit: The tRNA with the anticodon UAC is pre-attached to a methionine as seen here.

 

[sps27]

All the codons in the table refer to the mRNA and what amino acid they correspond to, not the tRNA anticodon.

edit: The tRNA with the anticodon UAC is pre-attached to a methionine as seen here.

That's a great picture. Awesome! I appreciate your help so much, with all the pictures that you have added to help elucidate it better. I read on some websites that aminoacyl tRNA synthetase enzyme binds the correct amino acid with the correct tRNA based on anti-codon. So that is fine, I can accept that. It must be doing that somehow......

 

[icedragon]

lol, glad I could help - just one more thing about the enzyme you mentioned. You are correct about its function and what it does is prep the tRNA with the appropriate amino acid, but I doubt this information will be required on the MCAT.

 

[sps27]

lol, glad I could help - just one more thing about the enzyme you mentioned. You are correct about it's function and what it does is prep the tRNA with the appropriate amino acid, but I doubt this information will be required on the MCAT.

Wow......dunno where you get these pictures from. I can remember these pictures better than pages full of text. In fact, I am taking a color printout here at work................