Designer Genes C

[jaspattack]

Does the structure of tRNA come up often other than the fact that it has an anticodon on one end and an amino acid on another? Also, are Lac and Trp operons still relevant? They aren't explicitly stated in the rules, but it also probably falls under mechanisms of gene expression or something.

[eagerlearner102]

You should probably know aminoacyl synthetase and peptidyl transferase. It would be a good idea to know that ATP binds to the tRNA activating enzymes to attach amino acid to tRNA, leaving ATP to become AMP.

[farmerjoe279]

Long time no see.

When converting a DNA sequence to protein are these the following steps?

1. Convert DNA (5'-3') to mRNA (3'-5')
2. Flip mRNA (3'-5') to mRNA (5'-3')
3. Use codon table to convert RNA (5'-3') to protein.

I did a test where the answer key skipped the 2nd step, but I'm pretty sure that's incorrect because ribosomes can't read mRNA in the 3'-5' direction (according to google and my textbook it reads mRNA from 5' to 3').
Just wanted to ask you all to make sure I'm not missing anything.

Thanks!

[jaspattack]

Long time no see.

When converting a DNA sequence to protein are these the following steps?

1. Convert DNA (5'-3') to mRNA (3'-5')
2. Flip mRNA (3'-5') to mRNA (5'-3')
3. Use codon table to convert RNA (5'-3') to protein.

I did a test where the answer key skipped the 2nd step, but I'm pretty sure that's incorrect because ribosomes can't read mRNA in the 3'-5' direction (according to google and my textbook it reads mRNA from 5' to 3').
Just wanted to ask you all to make sure I'm not missing anything.

Thanks!

You're right that ribosomes can't read RNA in the 3' to 5' direction, but you're wrong about the idea that RNA runs from 3' to 5'. The DNA is read by the RNA polymerase from 3' to 5' so the RNA is built from 5' to 3'. This way, it matches the sense (coding) strand instead of the antisense strand that it's replicated from. Since translation reads from 5' to 3', no flipping needs to occur.

[farmerjoe279]

Long time no see.

When converting a DNA sequence to protein are these the following steps?

1. Convert DNA (5'-3') to mRNA (3'-5')
2. Flip mRNA (3'-5') to mRNA (5'-3')
3. Use codon table to convert RNA (5'-3') to protein.

I did a test where the answer key skipped the 2nd step, but I'm pretty sure that's incorrect because ribosomes can't read mRNA in the 3'-5' direction (according to google and my textbook it reads mRNA from 5' to 3').
Just wanted to ask you all to make sure I'm not missing anything.

Thanks!

You're right that ribosomes can't read RNA in the 3' to 5' direction, but you're wrong about the idea that RNA runs from 3' to 5'. The DNA is read by the RNA polymerase from 3' to 5' so the RNA is built from 5' to 3'. This way, it matches the sense (coding) strand instead of the antisense strand that it's replicated from. Since translation reads from 5' to 3', no flipping needs to occur.

That makes sense, so 5'-CTTCGGGAA-3' DNA would not result in Phe-Pro-Lys?

[jaspattack]

Long time no see.

When converting a DNA sequence to protein are these the following steps?

1. Convert DNA (5'-3') to mRNA (3'-5')
2. Flip mRNA (3'-5') to mRNA (5'-3')
3. Use codon table to convert RNA (5'-3') to protein.

I did a test where the answer key skipped the 2nd step, but I'm pretty sure that's incorrect because ribosomes can't read mRNA in the 3'-5' direction (according to google and my textbook it reads mRNA from 5' to 3').
Just wanted to ask you all to make sure I'm not missing anything.

Thanks!

You're right that ribosomes can't read RNA in the 3' to 5' direction, but you're wrong about the idea that RNA runs from 3' to 5'. The DNA is read by the RNA polymerase from 3' to 5' so the RNA is built from 5' to 3'. This way, it matches the sense (coding) strand instead of the antisense strand that it's replicated from. Since translation reads from 5' to 3', no flipping needs to occur.

That makes sense, so 5'-CTTCGGGAA-3' DNA would not result in Phe-Pro-Lys?

The strand you just posted would be the sense (coding) strand. The complete strand of DNA would be:
5'-CTTCGGGAA-3'
3'-GAAGCCCTT-5'
Since the RNA is replicated from the 3'-5' (antisense) strand of DNA, it matches the 5'-3' strand instead of being complementary to it. Since that's the case, the resulting RNA would be CUUCGGGAA instead of GAAGCCCUU. The answer is probably Leu-Arg-Glu instead of Phe-Pro-Lys.

[farmerjoe279]

You're right that ribosomes can't read RNA in the 3' to 5' direction, but you're wrong about the idea that RNA runs from 3' to 5'. The DNA is read by the RNA polymerase from 3' to 5' so the RNA is built from 5' to 3'. This way, it matches the sense (coding) strand instead of the antisense strand that it's replicated from. Since translation reads from 5' to 3', no flipping needs to occur.

That makes sense, so 5'-CTTCGGGAA-3' DNA would not result in Phe-Pro-Lys?

The strand you just posted would be the sense (coding) strand. The complete strand of DNA would be:
5'-CTTCGGGAA-3'
3'-GAAGCCCTT-5'
Since the RNA is replicated from the 3'-5' (antisense) strand of DNA, it matches the 5'-3' strand instead of being complementary to it. Since that's the case, the resulting RNA would be CUUCGGGAA instead of GAAGCCCUU. The answer is probably Leu-Arg-Glu instead of Phe-Pro-Lys.

Welp, my textbook is wrong.

[eagerlearner102]

I think the easy way to remember is that 5'-->3' is the coding strand so it has to code for the sequence. The mRNA binds to template strand (3'-->5') so mRNA can be 5'-->3' by complementary base pairing.

[cclinton2]

I wrote a test for Designer Genes C at one of my states' regional competitions but I'm not sure how to upload the test and key files to the test exchange. Last competition season I wrote a Solar Systems B test and got it up on the wiki without any problems, but now that the test exchange isn't tied to the wiki I have no clue how to use it.

[jaspattack]

I wrote a test for Designer Genes C at one of my states' regional competitions but I'm not sure how to upload the test and key files to the test exchange. Last competition season I wrote a Solar Systems B test and got it up on the wiki without any problems, but now that the test exchange isn't tied to the wiki I have no clue how to use it.

People can't upload to the test exchange at the moment. The 2020 Test Exchange Wiki is where you should put tests you've written yourself, I believe.