biology anyone any good?

[troung]

I have a take home assignment to do. We are allowed to us any source to work on it. There do seem to be a lot of smart people here so here goes...

A student discovered a mutation in a gene encoding a tRNA such that the anticodon of the tRNA - 3' AUU instead of 3' AUG. Assume that this tRNA still carries the same amino acid. What will be the effect on proein synthesis?

Anyone know the answer?

[illusha]

is this college biology? I know this isn't high school

[platinum786]

I don't think it can synthesis can it?

I used to an expert at this, then i decided to study computing, bigest mistake of my life ever.

[Karthik]

Originally Posted by troung

I have a take home assignment to do. We are allowed to us any source to work on it. There do seem to be a lot of smart people here so here goes...

A student discovered a mutation in a gene encoding a tRNA such that the anticodon of the tRNA - 3' AUU instead of 3' AUG. Assume that this tRNA still carries the same amino acid. What will be the effect on proein synthesis?

Anyone know the answer?

Well troung, hope this is OK :

Out of the 22 tRNA anticodons available, AUU and AUG both signify the stop stage of transcription.

So this actually means that if there is a mutation that changes a AUU code to AUG in a tRNA, then the end process will still end up producing the same amino acid, meaning there will be no change.

AUG, AUU and ACU are three codes for the same stop state operation.

Dude,hope that answers your question in time for your assignment !

[barrowaj]

Originally Posted by Karthik

Well troung, hope this is OK :

Out of the 22 tRNA anticodons available, AUU and AUG both signify the stop stage of transcription.

So this actually means that if there is a mutation that changes a AUU code to AUG in a tRNA, then the end process will still end up producing the same amino acid, meaning there will be no change.

AUG, AUU and ACU are three codes for the same stop state operation.

Dude,hope that answers your question in time for your assignment !

Nice. I just looked this up to check. The mRNA stop codons are: UAA, UAG, and UGA (5' - 3'). That would make the (3' - 5') tRNA anticodons AUU, AUC, and ACU. Note that I got AUC instead of AUG for the 3rd stop codon... I think that AUG would correspond to the mRNA codon UAC, which actually codes for Tyrosine...

However, Karthik seems to know what he is talking about, and perhaps it is the 3rd base position wobble that accounts for this anomaly. Note that I haven't actually looked up the tRNA anticodons, I've just gone off of what the complimentary mRNA sequences are.

[Asim Aquil]

Originally Posted by platinum786

I don't think it can synthesis can it?

I used to an expert at this, then i decided to study computing, bigest mistake of my life ever.

I had taken Biology as a filler subject. Scored the highest in Biology, in the entire freakin school. Folks were all over me to get into med school. But I got into computers... !

Didn't turn out so bad, eventually. But Dr. Sid M.D. would've had a nice ring to it, as well.

[troung]

Nice. I just looked this up to check.

Well troung, hope this is OK

Thanks guys so much

I am not a science expert but had to take this class to finish up at school.

I have just two more questions actually (had a total of 30 to do by Saturday)

Here is one...

A. For the following DNA sequence (at the bottom), write and label the mRNA , the tRNA and the amino acid sequence using the codon table.

B. After you have done this rewrite the DNA sequence to reflect a point mutation.

C. Write it again to reflect a frameshift mutation. Please include the changes in the amino acid sequence for hte mutations also.

TAC CAT ACA ACC AGT

-------------

[barrowaj]

Originally Posted by troung

A. For the following DNA sequence (at the bottom), write and label the mRNA , the tRNA and the amino acid sequence using the codon table.

For this one you just need to do the following: write the mRNA compliment of the sequence. So A:T G:C, except instead of T (thymine), substitute U (uracil). For the tRNA sequences, just find the complement again, still using uracil. You should know what I am talking about, otherwise you are screwed when it comes to test time. For the amino acid sequence you can just look up the three base code on the mRNA table to figure out what aa it will produce.

Originally Posted by troung

B. After you have done this rewrite the DNA sequence to reflect a point mutation.

Just change one of the bases to something else.

Originally Posted by troung

C. Write it again to reflect a frameshift mutation. Please include the changes in the amino acid sequence for hte mutations also.

Insert an extra base into the sequence, or delete one from the sequence. Basically, if this happens during your replication the product is ****ed.

[troung]

Thanks man!!!

You do this for a living

[Karthik]

Hmm...nice one barrowaj

[The Chap]

God how I've destroyed my brain.

I did Nat-Sci at Camb as my first degree. I now have no bloody clue without hunting through old books. I could mention something about the question not specifying the medium ... etc.

But that would be an extended essay regarding ...

No; I just remembered my mislayed ramble telling you to stop cheating. Go and read a bloody book or pay attention in lectures. Cheeky sod! (for which full credit - I would have chanced my arm too!)

[barrowaj]

Originally Posted by The Chap

I did Nat-Sci at Camb as my first degree. I now have no bloody clue without hunting through old books. I could mention something about the question not specifying the medium

Then I'm sure you know your stuff. Its not like I pulled this stuff off the top of my head either. Actually, my degree was in electrical engineering, but I had to take a lot of biology and chemistry credits as medical school prerequisites.