Practice Questions - Week 4 - Proteins structure and function

Question 1

The overall folding of a single protein subunit is called:

a) primary structure

b) secondary structure

c) tertiary structure

d) quaternary structure

e) All of the above

Answer 1

c)

(The overall 3D structure of a single polypeptide (amino acid chain) is the tertiary. A fully functional 3D structure protein can also be quaternary but this involves more than one polypeptide chain)

Question 2

What happens when a protein is denatured?

a) Secondary structure is disrupted but its primary structure remains intact.

b) Primary structure is disrupted but its secondary structure remains intact.

c) It is broken apart into its constituent amino acids.

d) It becomes an alpha-helix.

Answer 2

a)

(Higher order structures are held together by weak non-covalent interactions thus can be disrupted with heat or chemicals. The primary structure - that is the amino acids chain is held tightly together by peptide bonds, which are strong covalent associations, thus cannot easily break)

Question 3

Secondary structures that repeat over and over in patterns are called:

a) primary structure

b) domains

c) prosthetic groups

d) super-secondary structures

Answer 3

d)

(These are also called MOTIFS - repeating patterns of helices or sheets, often found in tertiary structures)

Question 4

Crossword (to be completed)

Answer 4

2. Helix
   1.