Quiz 10

1. Consider this DNA sequence. What will its RNA transcript be?

UACUUAAAUUUUCUUAAUAAAUUAUAGUUA

ATGAATTTAAAAGAATTATTTAATATCAAT

AUGAAUUUAAAAGAAUUAUUUAAUAUCAAU

UTGUUTTTUUUUGUUTTUTTTUUTUTCUUT

The transcript will be an exact copy of the coding strand (ie, the one that starts with a start codon {ATG}), but the thymines (T) will be replaced with uracil (U).

Explanation

The transcript will be an exact copy of the coding strand (ie, the one that starts with a start codon {ATG}), but the thymines (T) will be replaced with uracil (U).

2. What type of mutation occurred in Question 4?

Missense mutation

Silent mutation

Nonsense Mutation

Frameshift Mutation

because there was a deletion that was not a multiple of 3 that resulted in a change of reading frame, this is a frameshift mutation.

Explanation

because there was a deletion that was not a multiple of 3 that resulted in a change of reading frame, this is a frameshift mutation.

3. What is the protein sequence of the RNA transcript generated in Question 1?

MET ASN LEU LYS GLU LEU PHE ASN ILE ASN

TYR LEU ASN PHE LEU ASN LYS LEU STOP

MET ASN LEU PHE LEU ASN LYS LEU STOP

Using the codon table, translate the triplet codes from the coding strand

Explanation

Using the codon table, translate the triplet codes from the coding strand

4. Another mutation occurs subsequently, and nucleotide number 9 is deleted entirely so the sequence is one base shorter overall. What is the resulting protein sequence?

MET ASN LEU LYS GLU LEU PHE ASN ILE ASN

TYR LEU ASN PHE LEU ILE ASN TYR MET

MET TYR LEU ASN PHE LEU ILE ASN TYR MET

MET ASN LEU LYS ASN TYR LEU ILE SER

Losing nucleotide #9 will alter the reading frame and result in new codons downstream of the mutation. Using the codon table, translate the new sequence (atgaatttaaagaattatttaatatcaat)

Explanation

Losing nucleotide #9 will alter the reading frame and result in new codons downstream of the mutation. Using the codon table, translate the new sequence (atgaatttaaagaattatttaatatcaat)

5. A mutation occurs in the DNA sequence from Question 1. Nucleotide number 9 is now a "G". What type of mutation is this?

Missense mutation

Nonsense mutation

Silent mutation

Frameshift mutation

Nuc #9 is an A, and it is part of the codon TTA (leucine). If it is changed to a G, it will now generate a TTG codon (leucine). Since this mutation will still result in the addition of leucine, it is silent.

Explanation

Nuc #9 is an A, and it is part of the codon TTA (leucine). If it is changed to a G, it will now generate a TTG codon (leucine). Since this mutation will still result in the addition of leucine, it is silent.