Point mutation, change in rna and protein

In summary, the conversation discusses how UV rays can cause point mutations in DNA, which are usually corrected by the excision repair mechanism but can sometimes be left out. The conversation then presents two scenarios where a nucleotide "T" is inserted after a bolded nucleotide, and asks if this will result in changes in the mRNA and protein sequences. There is uncertainty about the answer due to unclear information about the coding sequence.
  • #1
Raghav Gupta
1,011
76

Homework Statement



UV Rays is said to induce point mutations which get incorporated during the DNA replication process. These mutations are corrected by the excision repair mechanism of the DNA polymerase but sometimes they might be left out. In one of such cases, point insertions were incorporated. The DNA sequence is given as under
5'GTGTCCGTCTAATATTGTGAGATGTTATATCCCGCCGTCAACACCATCAACAGGATAATCGCCTGCTGGGGCAAAGGCGGTGAAG 3’
i) The nucleotide “T “is inserted after the “G” which has been bolded. Will the mRNA and the protein sequence change?
ii) The nucleotide “T” is inserted after the bolded “T”. What are the changes in mRNA and the protein?
2.

Homework Equations


Can't think for this question which is applicable.

The Attempt at a Solution


It is looking to me a frameshift mutation in both cases, so there will be completely different mRNA and proteins form. But I do not know properly that what I am thinking is correct or not.
 
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  • #2
Can you say what the changed protein sequence will be in each case?
 
  • #3
Ygggdrasil said:
Can you say what the changed protein sequence will be in each case?
The original protein sequence is:
Valine- Serine- Valine- Stop-......etc.
But, we should not go further since the stop codon UAA comes.
Here in question 5'...3' dna strand is non-template strand and mRNA sequence would be that of strand by substituting U in place of T.
Mutation is anyway taking place after that codon, so it does not matter.
So these answer my both questions that is no change in protein sequence?
So to this question, only this much answer?
 
  • #4
It depends which part of the sequence is considered the coding sequence. For example, there is a start codon further down. Is that AUG the start of the coding sequence or is the stop codon at the beginning the end of the coding sequence? It's unclear from the information you've given.
 
  • #5
So how do I answer this question?
It was given to us as an assignment and I am having confusion.
 
  • #7
If this question comes in test, having probability of coming 1/5, is my logic of answering correct? I don't have a class with my instructor till the test takes place.
Or should I mail him this question, though don't know if someone answers in a mail subject questions and it is not good to ask in a mail.
 

1. What is a point mutation?

A point mutation is a type of genetic mutation that involves a change in a single nucleotide base pair in the DNA sequence. This can result in a change in the corresponding RNA sequence and potentially a change in the protein that is produced.

2. How does a point mutation affect RNA?

A point mutation can affect RNA by causing a change in the sequence of nucleotides, which can result in a different amino acid being incorporated into the protein during translation. This can alter the structure and function of the protein.

3. Can a point mutation change the amino acid sequence of a protein?

Yes, a point mutation can change the amino acid sequence of a protein. This is because a point mutation can cause a change in the RNA sequence, which can result in a different amino acid being incorporated into the protein during translation.

4. What is the significance of a point mutation in protein structure?

A point mutation can have significant effects on protein structure. It can lead to a change in the shape and function of the protein, which can impact its ability to carry out its normal biological functions. This can have consequences for the overall health and development of an organism.

5. How do scientists study the effects of point mutations on proteins?

Scientists use a variety of techniques to study the effects of point mutations on proteins. This can include genetic engineering to create specific mutations, biochemical assays to measure protein function, and structural analysis to determine changes in protein structure.

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