Question

three different proteins were isolated from the same bacterial cells and their biological activity measured. each protein was then subjected to 10 - minute periods of increasing temperature, followed by measurement of biological activity. the results are shown in the table. based on these data, which statement is correct? protein b contains no disulfide bonds, whereas proteins a and c likely contain disulfide bonds. secondary structure in protein b is weaker than secondary structure in protein a or protein c. interactions between r groups in protein a add up to greater stabilization of tertiary structure than interactions between r groups in protein b or protein c. protein b is smaller than proteins a or c, giving it fewer amino acid r groups that can interact to stabilize its tertiary structure.

Explanation:

Disulfide bonds contribute to protein stability. Proteins with more stable tertiary structures (due to stronger R - group interactions) tend to retain biological activity better at higher temperatures. Protein A retains activity better than B and C, indicating stronger interactions between R groups stabilizing its tertiary structure. There is no evidence to suggest protein size or presence of disulfide bonds based on the given information about temperature - activity relationship.

Answer:

Interactions between R groups in Protein A add up to greater stabilization of tertiary structure than interactions between R groups in Protein B or Protein C.