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farmerjoe279 wrote: ↑January 31st, 2020, 7:58 am 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 wrote: ↑January 31st, 2020, 12:01 pm

farmerjoe279 wrote: ↑January 31st, 2020, 7:58 am 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 wrote: ↑January 31st, 2020, 12:07 pm

jaspattack wrote: ↑January 31st, 2020, 12:01 pm

farmerjoe279 wrote: ↑January 31st, 2020, 7:58 am 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 wrote: ↑January 31st, 2020, 3:21 pm

farmerjoe279 wrote: ↑January 31st, 2020, 12:07 pm

jaspattack wrote: ↑January 31st, 2020, 12:01 pm

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.

cclinton2 wrote: ↑February 7th, 2020, 1:00 pm 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.