Protein Structure/Hemoglobin/Collagen

Question 1

What are three chemical interactions that maintain protein structure?

Answer 1

Hydrophobic interaction
Hydrogen bonds
Electrostatic interactions

Question 2

What amino acids can be phosphorylated and why?

Answer 2

Serine, Tyrosine, Threonine

Because they have OH hydroxyl groups

Question 3

What amino acid genetic mutation causes sickle cell anemia?

Answer 3

glutamine (-) to valine (neu)

Question 4

What is the lifetime of a healthy red blood cell?

Answer 4

120 days

Question 5

What is different about HbA1c?

Answer 5

It is glycosylated on the N-terminal valine of the beta chain.

Question 6

What hemoglobin form is used to measure blood glucose levels in diabetics?

Answer 6

HbA1c

Question 7

Oxygen binds to what oxidation state of Fe in hemoglobin?

Answer 7

Fe+2

Question 8

In terms of hemoglobin, what is positive cooperativity?

Answer 8

Binding the first O2 increases affinity of the other subunits

Question 9

What are tense and relaxed states of Hb subunits?

Answer 9

Tense = low O2 affinity
Relaxed = high O2 affinity

Question 10

What does low pH do to Hb O2 affinity?

Answer 10

decreases it

Question 11

What is the most abundant protein in mammals

Answer 11

collagen

Question 12

What is the basic structural unit fo collagen?

Answer 12

3 strand helix called tropocollagen

Question 13

The distribution of what hydrophobic aa side chain forces collagen into a left hand helix.

Answer 13

Proline

Question 14

What does vitamin C (ascorbate) used for in collagen?

Answer 14

It reduces proline to hydroxyproline.

Hydroxyproline increases stability of the triple helix via hydrogen bonds.

Question 15

Collagen is strengthened by covalent cross links from what amino acid side chain?

Answer 15

Lysine

Question 16

How does copper deficiency affect collagen?

Answer 16

Lysine cross links do not form

Question 17

Why does collagen need cross links?

Answer 17

Without them collagen is susceptible to proteases

Question 18

Osteogenesis Imperfecta

Answer 18

Defective collagen

brittle bones

Question 19

Ehlers-Danlos syndrome

Answer 19

Connective tissue problems due to collagen defects

Question 20

Vitamin D synthesis in the body is initiated by what?

Answer 20

UVB rays

Question 21

Vitamin D is synthesized from what molecule?

Answer 21

cholesterol

Question 22

Low calcium stimulates the release of what hormone?

Answer 22

Parathyroid Hormone (PTH)

Question 23

What is the active form of vitamin D?

Answer 23

1,25-Dihydroxycholecalciferol

calcitriol

Question 24

Where to steroid hormones bind to their receptors?

Answer 24

Inside of the cell

Question 25

What does vitamin D (calcitriol) do in the body?

Answer 25

It helps to regulate calcium concentration in the blood.

Calcitriol stimulates bones to uptake calcium for bone growth and maintenance. PTH does the opposite