Question 1

Which of the following best describes the tertiary structure of a protein?

Accepted Answer

The spatial arrangement of the secondary structural elements in the polypeptide chain

Question 2

Which of the following interactions is NOT a major contributor to the stabilization of protein tertiary structure?

Accepted Answer

Peptide bonds

Question 3

A mutation replaces a hydrophobic residue in the core of a globular protein with a charged residue. What is the most likely effect on protein stability?

Accepted Answer

The protein will become less stable due to disruption of the hydrophobic core.

Question 4

Which of the following statements about alpha helices is CORRECT?

Accepted Answer

Side chains radiate outward from the helix axis.

Question 5

Which of the following best explains the 'hydrophobic effect' in protein folding?

Accepted Answer

Hydrophobic side chains cluster in the interior, releasing ordered solvent molecules and increasing solvent entropy.

Question 6

Which of the following is a characteristic feature of beta sheets in proteins?

Accepted Answer

Side chains alternate above and below the plane of the sheet.

Question 7

Which of the following is TRUE regarding fibrous proteins such as collagen and keratin?

Accepted Answer

They have elongated structures with well-defined secondary structures.

Question 8

A protein domain is best described as:

Accepted Answer

A compact, independently folding unit within a protein, often with a specific function.

Question 9

Which of the following statements about protein quaternary structure is CORRECT?

Accepted Answer

It describes the spatial arrangement of multiple polypeptide chains in a multisubunit complex.

Question 10

Which of the following is a consequence of forming disulfide bonds in proteins?

Accepted Answer

Increased protein stability by covalently linking different parts of the polypeptide chain.

Question 11

A protein with $$D_2$$ symmetry would have which of the following features?

Accepted Answer

Three 2-fold axes of symmetry

Question 12

Which of the following best describes the arrangement of side chains in a beta sheet?

Accepted Answer

Side chains alternate above and below the plane of the sheet.

Question 13

Which of the following is a thermodynamic factor that opposes protein folding?

Accepted Answer

Unfavorable loss of conformational entropy

Question 14

Which of the following proteins is an example of a fibrous protein that provides elasticity due to its structure?

Accepted Answer

Silk fibroin

Question 15

Which of the following is a real-life example of a protein with helical symmetry capable of indefinite growth?

Accepted Answer

Actin

Question 16

A mutation disrupts the ability of a protein to bind its prosthetic group. What is the most likely effect?

Accepted Answer

The protein will lose stability and may not function properly.

Question 17

Which of the following best describes the difference between parallel and antiparallel beta sheets?

Accepted Answer

Parallel beta sheets have all strands running N to C in the same direction, while antiparallel beta sheets have adjacent strands running in opposite directions.

Question 18

Which of the following is a plausible effect of introducing a proline residue into the middle of an alpha helix?

Accepted Answer

It will disrupt the helix due to proline's rigid structure.

Question 19

Which of the following is TRUE regarding protein domains?

Accepted Answer

A typical domain is about 200 amino acids and can fold independently.

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