Questions 9 to 13 are in reference to the DNA sequence shown in Question 8. Here
ID: 135871 • Letter: Q
Question
Questions 9 to 13 are in reference to the DNA sequence shown in Question 8.
Here is Question 8.
Question 8:
The top strand of the following segment of DNA serves as the template strand:
3’ TACACCTTGGCGACGACT 5’
5’ ATGTGGAACCGCTGCTGA 3’
We will refer to this segment of DNA as the original (or unmutated) sequence.
Please answer the following questions:
(a) What is the mRNA sequence?
The mRNA sequence is 5' 3'. (2 marks)
**Please enter your sequence in the 5' to 3' direction. Deductions will be made if a sequence is inputted in the wrong direction.**
(b) Using the mRNA sequence you determined in part (a) of this question, give the sequence of the protein that would be translated.
The amino acid sequence for this protein is N-terminus C-terminus. (2 marks)
**Please note**
The N-terminus refers to the beginning of the primary sequence for a protein, and the C-terminus refers to the end of the primary sequence for a protein.
i.e. input the amino acids in the order that they would be translated.
If a codon encodes for a stop codon, type STOP.
When inputting your sequence, separate each amino acid with a hyphen (e.g. Ser-Tyr-STOP).
You will need to consult the genetic code to answer this question.
Question 10:
The original (unmutated) DNA sequence (shown above in Question 8) has been mutated to the following (this represents the template strand):
3’ TACGACCTTGGCGACGACT 5’
We will refer to this sequence as mutation #2.
Please note that for simplicity only the template strand for this mutated segment of DNA is shown.
Answer the following questions:
(a) What is the complete mRNA sequence for the mutated segment mutation #2?
The mutated mRNA sequence is 5' 3'. (2 marks)
**Please enter your sequence in the 5' to 3' direction. Deductions will be made if a sequence is inputted in the wrong direction.**
(b) Using the mRNA sequence you determined in part (a) of this question, give the sequence of the protein that would be translated.
The amino acid sequence for this protein is N-terminus C-terminus. (2 marks)
**Please note**
The N-terminus refers to the beginning of the primary sequence for a protein, and the C-terminus refers to the end of the primary sequence for a protein.
i.e. input the amino acids in the order that they would be translated.
If a codon encodes for a stop codon, type STOP.
When inputting your sequence, separate each amino acid with a hyphen (e.g. Ser-Tyr-STOP).
You will need to consult the genetic code to answer this question.
4 points
QUESTION 11
Questions 9 to 13 are in reference to the DNA sequence shown in Question 8.
Question 11:
The original (unmutated) DNA sequence (shown above in Question 8) has been mutated to the following (this represents the template strand):
3’ TACACCTTAGCGACGACT 5’.
We will refer to this sequence as mutation #3.
Please note that for simplicity only the template strand for this mutated segment of DNA is shown.
Answer the following questions:
(a) What is the complete mRNA sequence for the mutated segment mutation #3?
The mutated mRNA sequence is 5' 3'. (2 marks)
**Please enter your sequence in the 5' to 3' direction. Deductions will be made if a sequence is inputted in the wrong direction.**
(b) Using the mRNA sequence you determined in part (a) of this question, give the sequence of the protein that would be translated.
The amino acid sequence for this protein is N-terminus C-terminus. (2 marks)
**Please note**
The N-terminus refers to the beginning of the primary sequence for a protein, and the C-terminus refers to the end of the primary sequence for a protein.
i.e. input the amino acids in the order that they would be translated.
If a codon encodes for a stop codon, type STOP.
When inputting your sequence, separate each amino acid with a hyphen (e.g. Ser-Tyr-STOP).
You will need to consult the genetic code to answer this question.
4 points
QUESTION 12
Questions 9 to 13 are in reference to the DNA sequence shown in Question 8.
Question 12:
(1 mark each)
In reference to the original sequence (shown in Question 8), classify each type of mutation present from Questions 9 to 11. Choose the best option for each.
mutation #1
mutation #2
mutation #3
base substitution - silent mutation
insertion - frameshift mutation
deletion - frameshift mutation
base substitution - missense mutation
base substitution - nonsense mutation
QUESTION 13
Questions 9 to 13 are in reference to the DNA sequence shown in Question 8.
Question 13:
Most mutations have a neutral effect on the phenotype, function or survival of an organism because they do not elicit any noticeable change. Whereas other mutations can have a positive effect on an organism leading to new versions of proteins that help an organism adapt to changes in its environment; while other mutations can have a negative effect on the organism and result in a protein that does not function normally or at all.
Answer the following questions based on the responses you gave above in Questions 8 to 12.
(a) Based on the protein sequences that were produced as a result of mutation #1, mutation #2, or mutation #3, describe the effect, if any, these mutations would likely have on the function of the protein within the cell. Support your answer. (3 marks)
(b) If these mutations occurred within a germline cell and not a somatic cell, how would the effects of these mutations differ? (2 marks)
mutation #1
mutation #2
mutation #3
A.base substitution - silent mutation
B.insertion - frameshift mutation
C.deletion - frameshift mutation
D.base substitution - missense mutation
E.base substitution - nonsense mutation
Explanation / Answer
The DNA sequence encoding the above 5 amino acids is included within the sequence below.
5’-AACCGAATTCCATGTTATAGC-3’ 3’-TTGGCTTAAGGTACAATATCG-5’
You isolate and sequence the following two different mutant alleles of Gene
Mutant 1 -
AACCAAATTCCATGTTATAGC-3’
Mutant 2 -
TTGGTTTAAGGTACAATATCG-5’
5’-AACCGTATTCCATGTTATAGC-3’ 3’-TTGGCATAAGGTACAATATCG-5’
Mutant 1 will not alter the folding of Protein A since this is an example of silent point mutation that does not alter the amino acid sequence of the protein.
Mutant 2 is an example of missense point mutation that changes the codon 5’AAU3’ (coding for asn106) to 5’UAU3’ (coding for tyr106) thus altering the folding of this protein.
You identify a disease of epidermal cells in mice in which Gene A is not transcribed. Further analyses reveals that the sequence of Gene A in affected and normal mice is the SAME.
Mature mRNA corresponding to Gene A lacks the 5 methyl Cap and 3’ Poly A tail
DNA around the promoter region of Gene A.
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