Protein structure (non-covalent forces)

Question 1

What does the folding of a protein in 3D allow amino acids to do?

Answer 1

Allows amino acids that need to come close together in a specific orientation can do so to carry out the function

Question 2

Is the folding of a protein spontaneous or unspontaneous?

Answer 2

Spontaneous

Question 3

How do you calculate the energy of association, E, of 2 electric charges, q1 + q2?

Answer 3

E = (k x q1 x q2) / (D x r)
r = distance
D = dielectric constant of the medium
k = 9 x 10^9 JmC^-2
one electronic charge = 1.6 x 10^-19 C

Question 4

What is the relationship between the value of D and the strength of ionic interaction?

Answer 4

Larger value of D = weaker ionic interaction

Question 5

What is the dielectric constant of a solvent?

Answer 5

A measure of its ability to keep opposite charges apart

Question 6

What are dipole-induced dipole interactions?

Answer 6

A polar molecule causes the electron cloud in a non-polar molecule to shift, resulting in a dipole

Question 7

What are london dispersion forces?

Answer 7

-between 2 non-polar bonds
-electrons are continually moving around the bond, causing partial charges in the bond
-attraction between the opposite slight charges of 2 molecules

Question 7

What bond is the strongest of the non-covalent interactions?

Answer 7

Hydrogen bonding

Question 8

In a hydrogen bond, what is the bond length between the H and H acceptor, and the bond length of the H and H donor?

Answer 8

H and H acceptor = approx. 2.0A
H and H donor = approx. 0.9A

Question 9

Describe the enthalpy change of the folding of proteins?

Answer 9

Slightly -ive - comes from bond formation or breakage

Question 10

What is entropy change?

Answer 10

Measures the degree of order in a system