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protein synthesis confusion

hi,

so the coding strand which contains the genes?, needs to produce the amino acid methionine which = ATG

if mRNA makes a copy of this to join with a ribosome the outcome = AUG?

so if this mRNA containing the strand AUG joins with a ribosome and then a tRNA with the anticodon and amino acid binds to it, the anticodon would carry UAC?

so if UAC on tRNA carries its amino acid over, the amino acid wouldn't be methionine, it would be tyrosine?



if anyone can clear this up for me I'd really appreciate it, thanks in advance (:

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The mRNA sequence would be complementary to ATG so would be UAC, and then the anti-codon would be complementary to that as AUG, which would be methionine. The general thing to remember is that the base sequence in tRNA is the same as in the DNA, which the U replacing the T.

Does this help?
Original post by Tristian Fox
The mRNA sequence would be complementary to ATG so would be UAC, and then the anti-codon would be complementary to that as AUG, which would be methionine. The general thing to remember is that the base sequence in tRNA is the same as in the DNA, which the U replacing the T.

Does this help?



thanks for the reply,

so i think im confused about the template strand and the coding strand :s

i thought it was always the coding strand which contained the genes needed to be made.

however, if a copy of the coding strand is made onto the mRNA, which joins with an anticodon, the anticodon would present the base sequence found on the template strand?

so does this mean its the template strand which actually holds genes needed to be made?


thanks again
can anybody help me please?
Reply 4
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Dynamo123
7
Original post by ThePremierLeague
thanks for the reply,

so i think im confused about the template strand and the coding strand :s

i thought it was always the coding strand which contained the genes needed to be made.

however, if a copy of the coding strand is made onto the mRNA, which joins with an anticodon, the anticodon would present the base sequence found on the template strand?

so does this mean its the template strand which actually holds genes needed to be made?


thanks again


A little bit of clarification about the template and coding strand. The template strand is complementary to the mRNA sequence, whereas the coding strand can be thought to be mRNA like (only to avoid confusion.)


Now the coding strand contains the coding genes. Therefore while you're right there, it's the codon that actually determines the amino acid type. The anticodon itself is specific, i.e, 2 or 4 codons may code for arginine, but even then, for each of these, the anticodon is different.
Original post by Dynamo123
A little bit of clarification about the template and coding strand. The template strand is complementary to the mRNA sequence, whereas the coding strand can be thought to be mRNA like (only to avoid confusion.)


Now the coding strand contains the coding genes. Therefore while you're right there, it's the codon that actually determines the amino acid type. The anticodon itself is specific, i.e, 2 or 4 codons may code for arginine, but even then, for each of these, the anticodon is different.



thanks for response

if we take your example and say ok UUU and GGG are 2 codons which code for arginine.
the anticodons which would bind to them would be AAA and CCC.

AAA and CCC are different to UUU and GGG.
so how is arginine coded for as AAA and CCC arent what codes for the amino acid?
Reply 6
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Dynamo123
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Original post by ThePremierLeague
thanks for response

if we take your example and say ok UUU and GGG are 2 codons which code for arginine.
the anticodons which would bind to them would be AAA and CCC.

AAA and CCC are different to UUU and GGG.
so how is arginine coded for as AAA and CCC arent what codes for the amino acid?


I think I don't get what you are asking. AGA snd AGG for instance code for arginine. They are codons. The specific anticodon bearing tRNA binds to each amino acid by the action of an enzyme which is specific for each amino acid. Could you make the original question clear a bit?

Posted from TSR Mobile
Original post by Dynamo123
I think I don't get what you are asking. AGA snd AGG for instance code for arginine. They are codons. The specific anticodon bearing tRNA binds to each amino acid by the action of an enzyme which is specific for each amino acid. Could you make the original question clear a bit?

Posted from TSR Mobile



so the specific anticodons on tRNA for these codons would be UCU and UCC correct?
these anticodons however both code for serine not arginine?
Original post by Dynamo123
I think I don't get what you are asking. AGA snd AGG for instance code for arginine. They are codons. The specific anticodon bearing tRNA binds to each amino acid by the action of an enzyme which is specific for each amino acid. Could you make the original question clear a bit?

Posted from TSR Mobile



I guess i mean how does the complementary anticodon know what amino acid to bring?
Reply 9
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Dynamo123
7
Original post by ThePremierLeague
so the specific anticodons on tRNA for these codons would be UCU and UCC correct?
these anticodons however both code for serine not arginine?


Incorrect. The codon UCU and UCC code for serine, not the anticodons.
Reply 10
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Dynamo123
7
Original post by ThePremierLeague
I guess i mean how does the complementary anticodon know what amino acid to bring?


Using a simple approach the binding of the related anticodon bearing tRNA to the amino acid is mediated by an enzyme aminoacyl tRNA synthetase which in its action is specific for each amino acid. So the tRNA with anticodon for serine cannot bind to arginine because the enzyme does not permit it.

Does this help?
Reply 11
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Dynamo123
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Posted from TSR Mobile
http://www.phschool.com/science/biology_place/biocoach/translation/addaa.html

This might help,
Original post by Dynamo123


I think im starting to grasp it a bit better now, thank you (+ rep)

so basically the specific anticodon to a codon will always carry the amino acid coded for by the codon regardless of the fact that the actual base nucleotides are opposite?
Reply 13
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Dynamo123
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Original post by ThePremierLeague
I think im starting to grasp it a bit better now, thank you (+ rep)

so basically the specific anticodon to a codon will always carry the amino acid coded for by the codon regardless of the fact that the actual base nucleotides are opposite?


:biggrin:

Righto. The anticodon bearing tRNA is specific (like the aminoacyl tRNA synthetase) for each amino acid. So there are 64 codons, 61 tRNAs (excluding stop codons, they don't have tRNAs) and 20 different amino acid, as well as 20 aminoacyl tRNA synthetases.

I hope the picture is getting clearer now :smile:
Original post by Dynamo123
:biggrin:

Righto. The anticodon bearing tRNA is specific (like the aminoacyl tRNA synthetase) for each amino acid. So there are 64 codons, 61 tRNAs (excluding stop codons, they don't have tRNAs) and 20 different amino acid, as well as 20 aminoacyl tRNA synthetases.

I hope the picture is getting clearer now :smile:



hey Dynamo,

if u have the main OCR A2 textbook, would u be able to confirm something for me on p107?

I think theres a mistake on figure 3 - part 2 - as the codon AUA codes for the amino acid lsoleucine correct? however, the amino acid tyrosine is brought to the codon instead by the anticodon?

thanks in advance
Reply 15
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Dynamo123
7
Original post by ThePremierLeague
hey Dynamo,

if u have the main OCR A2 textbook, would u be able to confirm something for me on p107?

I think theres a mistake on figure 3 - part 2 - as the codon AUA codes for the amino acid lsoleucine correct? however, the amino acid tyrosine is brought to the codon instead by the anticodon?

thanks in advance


I don't have the OCR textbook. However, i have read your post on the other thread too, and I think I can clarify the problem. If not, then can you post a pic of the related figure?

The codons AUU, AUC and AUA code for Isoleucine. Tyrosine is encoded bu UAU and UAC. The problem in your book might either be a technical error, or it might be due to the confusion between codon and anticodon.

Tyrosine is brought by the tRNA with anticodon AUA to the mRNA with exposed codon UAU.cancer22.jpg

I hope that helps. :smile:
Original post by Dynamo123
I don't have the OCR textbook. However, i have read your post on the other thread too, and I think I can clarify the problem. If not, then can you post a pic of the related figure?

The codons AUU, AUC and AUA code for Isoleucine. Tyrosine is encoded bu UAU and UAC. The problem in your book might either be a technical error, or it might be due to the confusion between codon and anticodon.

Tyrosine is brought by the tRNA with anticodon AUA to the mRNA with exposed codon UAU.cancer22.jpg

I hope that helps. :smile:







hey this is the image from the textbook
anticodon.jpg334.9KB
if its not quite clear enough, the yellow = A, pink = U, green = C and blue = G
also the first two amino acids are met and tyr

thanks
Reply 18
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Dynamo123
7
Original post by ThePremierLeague
hey this is the image from the textbook


No the figure is wrong. Like I said before, the book mentions the codon as AUA, when it's actually UAU. This cannot simply be a printing error.
Original post by Dynamo123
No the figure is wrong. Like I said before, the book mentions the codon as AUA, when it's actually UAU. This cannot simply be a printing error.



right thanks!

so basically, the error is that the bases are attached to the wrong RNA on the figure,

in fact, the AUA should be on the tRNA and the UAU should be on the mRNA?

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