Questions and answers for exam Preparation

MCQs

Total Questions : 76 | Page 3 of 8 pages

Question 21. As folding progresses which of the following does not take place?

Entropy decreases
Amount of protein in native state increases
Free energy increases
Amount of protein in native state decreases

Discuss Question

Answer: Option D. -> Amount of protein in native state decreases
Answer: (d).Amount of protein in native state decreases

Question 22. Which of the following are chaperons in E.coli?

Hsp70
Hsp40
DnaA
DnaK and DnaJ

Discuss Question

Answer: Option D. -> DnaK and DnaJ
Answer: (d).DnaK and DnaJ

Question 23. Protein A will fold into its native state only when protein B is also present in the solution. However, protein B can fold itself into native confirmation without the presence of protein A. Which of the following is true?

Protein B serves as precursor for protein A
Protein B serves as molecular chaperon for protein A
Protein B serves as ligand for protein A
Protein B serves as structural motif for protein A

Discuss Question

Answer: Option B. -> Protein B serves as molecular chaperon for protein A
Answer: (b).Protein B serves as molecular chaperon for protein A

Question 24. Which of the following is true about ribonucease?

Native state which is catalytically inactive is denatured
Unfolded state is inactive
Renatured ribonuclease is inactive
Renaturation involves reestablishment of the correct disulfide cross links

Discuss Question

Answer: Option A. -> Native state which is catalytically inactive is denatured
Answer: (a).Native state which is catalytically inactive is denatured

Question 25. Which of the following about spontaneous folding is false?

It involves the initial formation of highly compact structure
It involves initial formation of a local secondary structure
It is essentially a random process
It may be defective in some human diseases

Discuss Question

Answer: Option C. -> It is essentially a random process
Answer: (c).It is essentially a random process

Question 26. Myoglobin binding of O₂ depends on ___________

Hemoglobin concentration
O₂ concentration and affinity of myoglobin for O₂
Ka
Kd

Discuss Question

Answer: Option B. -> O₂ concentration and affinity of myoglobin for O₂
Answer: (b).O₂ concentration and affinity of myoglobin for O₂

Question 27. When oxygen binds to a heme-containing protein, the two open coordination bonds of Fe²⁺ are occupied by___________

One O atom and one amino acid atom
One O₂ molecule and one amino acid atom
One O₂ molecule and one heme atom
Two O atoms

Discuss Question

Answer: Option B. -> One O₂ molecule and one amino acid atom
Answer: (b).One O₂ molecule and one amino acid atom

Question 28. The interactions of ligands with proteins are ___________

Relatively nonspecific
Relatively rare in biological systems
Usually irreversible
Usually transient

Discuss Question

Answer: Option D. -> Usually transient
Answer: (d).Usually transient

Question 29. Myoglobin and the subunits of hemoglobin have ___________

Very different primary and tertiary structures
Very similar primary and tertiary structures
Very similar primary structures, but different tertiary structures
Very similar tertiary structures, but different primary structures

Discuss Question

Answer: Option D. -> Very similar tertiary structures, but different primary structures
Answer: (d).Very similar tertiary structures, but different primary structures

Question 30. In the binding of oxygen to myoglobin, the relationship between the concentration of oxygen and the fraction of binding sites occupied can best be described as ___________