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 out from the helix axis, and hydrogen bonds are nearly parallel to 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 fibrous proteins is the main component of hair and fingernails?

Accepted Answer

Keratin

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 is a consequence of forming disulfide bonds in proteins?

Accepted Answer

Increased protein stability

Question 10

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

Accepted Answer

The spatial arrangement of multiple polypeptide chains to form multisubunit complexes.

Question 11

Which of the following is an example of a protein with helical symmetry capable of indefinite growth in length?

Accepted Answer

Actin

Question 12

A protein loses its function after a mutation disrupts a key ionic bond between two side chains. Which type of interaction has been affected?

Accepted Answer

Charge-charge interaction

Question 13

Which of the following statements about collagen is TRUE?

Accepted Answer

Collagen is a fibrous protein that serves as a matrix material in bone.

Question 14

Which of the following is a favorable thermodynamic factor in protein folding?

Accepted Answer

Formation of intramolecular hydrogen bonds

Question 15

A protein with three 2-fold axes of symmetry most likely exhibits which type of quaternary symmetry?

Accepted Answer

$$D_3$$ symmetry

Question 16

Which of the following best explains why silk fibroin is both strong and flexible?

Accepted Answer

It contains close-packed beta sheets interrupted by compact folded regions.

Question 17

Which of the following is a plausible effect of binding a prosthetic group to a protein?

Accepted Answer

It increases the protein's stability.

Question 18

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 19

A protein is found to have twofold symmetry about a $$C_2$$ axis. Which of the following best describes its quaternary structure?

Accepted Answer

It is a dimer with twofold symmetry.

Question 20

Which of the following is a direct consequence of the loss of conformational entropy during protein folding?

Accepted Answer

The folded state has only a few closely related conformations.

Chapter 6: The Three-Dimensional Structure of Proteins – Study Notes

스터디 가이드 - 연습 문제

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