Question

question 14
in proteins that contain the amino acid cysteine, what additional bond is found?
a hydrocarbon bond
a nitrogen carbon bond
a disulfide bond
a carbon oxygen bond

Explanation:

Cysteine is an amino acid with a sulfhydryl (-SH) group. When two cysteine residues come close, their sulfhydryl groups can oxidize to form a disulfide bond (-S-S-). This bond is crucial for protein tertiary and quaternary structures. Hydrocarbon bonds are general C - H bonds not specific to cysteine. Nitrogen - carbon bonds are common in peptide bonds (not unique to cysteine). Carbon - oxygen bonds are also widespread (e.g., in carbonyl groups) but not specific to cysteine - related additional bonds.

Answer:

C. A disulfide bond