Question

Normal DNA sequence: 5′-CCTGAGGAG-3′

Mutant DNA sequence: 5′-CCTGTGGAG-3′

A. The point mutation causes an amino acid replacement of (1)___________ by (2)___________ for the sixth amino acid of β-globin.

Answer 1

you cut the sequence in pieces of 3 nucleobases called codons.
for the normal sequence, the codons are CCT/GAG/CAG
The mutant sequence: CCT/GTG/GAG

In the diagram I added you can search the amino acids that are produced for all codon combinations. GAG codes for glutamic acid and GTG codes for valine. So this small change in the β-globin chain of haemoglobin causes glutamic acid to be replaced with valine at the sixth position, and that will result in sickle cell anemia.

Answer 2

Thanks! Ok, now is see. Glutamic acid, valine, ect are made up of a 3 letter combination of nucleobases: G,T,A,and C

Answer 3

ooh I forgot to add the diagram...
Sorry

Answer 4

haha thanks :)

Answer 5

And there are 5 nucleobases, A (adenine), G (guanine), T (thymine), C (cytosine) and U (uracil)
U only exists in RNA and thymine only appears in DNA (T in DNA = U in RNA)

Answer 6

That's why you don't see T in the codon table, it's the same as U

Answer 7

Ohh one more thing if you have time, what did the question mean by: for the sixth amino acid. I know what it was talking about just not what it means

Answer 8

They're talking about the sixth position in the β-globin chain of haemoglobin. When this posision (codon) is point-mutated, the person has sickle cell anemia)

Answer 9

position*

Answer 10

But I think the only thing you need to worry about is how to find amino acids for the different codons :)

Answer 11

ok, thanks. :)

Answer 12

You're welcome \(\huge\ddot\smile\)