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Hi, there is a question on EK biology 30 minute exams lecture 3, question 54.
It is stated in the passage that "Each single strand of DNA in an IS element possess a nucleotide sequence at one end that is complementary to the reverse sequence of nucleotide at its other end"
The question: One strand of an IS element begins with the nucleotide sequence 5'-ACTGTTAAG-3'. The same strand must end with the nucleotide sequence:
A. 5'-GAATTGTCA-3'
B. 5'-TGACAATTC-3'
C. 5'-CTTAACAGT-3'
D. 5'-ACTGTTAAG-3'
I chose B, but the back of the book told me the correct answer is C, and this is their explanation: "The passaqe says that the ends of the strands are reverse compliments of each other. The complement sequence is 5'TGACAATTC-3'. The reverse of this is 5'-CTTAACAGT-3'."
So the idea is, we should take the reverse sequence, then the complement of that reverse sequence. You can do the complement first and then reverse the complement too, it's the same thing.
Shouldn't the complement sequence be 5'-TGACAATTC-3', and thus making B the correct answer?? Basically, when they didn't make the complementary sequence anti-parallel to the reverse sequence. I.e. the complement of 5' AAC 3' should be 3' TTG 5', or 5'GTT3'.
It is stated in the passage that "Each single strand of DNA in an IS element possess a nucleotide sequence at one end that is complementary to the reverse sequence of nucleotide at its other end"
The question: One strand of an IS element begins with the nucleotide sequence 5'-ACTGTTAAG-3'. The same strand must end with the nucleotide sequence:
A. 5'-GAATTGTCA-3'
B. 5'-TGACAATTC-3'
C. 5'-CTTAACAGT-3'
D. 5'-ACTGTTAAG-3'
I chose B, but the back of the book told me the correct answer is C, and this is their explanation: "The passaqe says that the ends of the strands are reverse compliments of each other. The complement sequence is 5'TGACAATTC-3'. The reverse of this is 5'-CTTAACAGT-3'."
So the idea is, we should take the reverse sequence, then the complement of that reverse sequence. You can do the complement first and then reverse the complement too, it's the same thing.
Shouldn't the complement sequence be 5'-TGACAATTC-3', and thus making B the correct answer?? Basically, when they didn't make the complementary sequence anti-parallel to the reverse sequence. I.e. the complement of 5' AAC 3' should be 3' TTG 5', or 5'GTT3'.
