Question

what is the approximate length of a DNA coding sequence of lysozyme a protein of 129 amino acids?
a.132nm
b.113nm
c.66nm
d.44nm
​

Answer 1

Answer:

a.132nm

Explanation:

Distance between two base pairs = 3.4 Angstrom

Amino acid occurs in triplets. Hence 129 amino acids imply 3×129 base pairs = 387 base pairs

Length of DNA = Total base pairs × Distance between two pairs

Implies Length= 387 ×3.4 Angstrom

Approximately = 132nm.

Thus the approximate length of a DNA coding sequence of lysozyme a protein of 129 amino acids is 132nm

Answer 2

The approximate length of a DNA coding sequence of lysozyme a protein of 129 amino acids is 132nm.

We know that each codon has 3 bases and 1 codon forms 1 amino acid.

So, for 129 amino acids no. of base pairs required=

3 X 129 = 387 base pairs

Distance between two base pairs in B DNA = 3.4 Angstrom

Length of DNA = 3.4 Angstrom X No. of base pairs

= 3.4 X 387

=1315 Angstrom

= 131.5 nm ≈ 132nm