Answer:
a. a polypeptide with four cysteines has two disulfide bonds
b. a polypeptide with six cysteines has three disulfide bonds
c. a polypeptide with 8 cysteines has four disulfide bonds
d. a polypeptide with 10 cysteines has five disulfide bonds
Explanation:
A disulfide bond is formed by two sulphur atoms linked covalently. Since it specifically require two linked sulphur atoms, and cysteine contains just one sulphur atom, then a polypeptide with an even number of cysteine molecules will have disulfide bonds halved the number of cysteine molecules.
Therefore, a polypeptide with even numbers of cysteine molecules like:
4 has 2 disulfide bonds;
6 has 3 disulfide bonds:
8 has 4 disulfide bonds;
10 has 5 disulfide bonds
