Vitamins (Module 3 Lecture 6)

Question 1

What are five important things to know about vitamins?

Answer 1

1. They are essential organic molecules (required in the diet and cannot be synthesized by body).
2. They are usually enzymatic cofactors.
3. They play catalytic roles, not structural.
4. Only needed in small amounts.
5. Found in cells and cellular foods (most contain nitrogen, not present in sugars and fats).

Question 2

What B vitamins are required for cells in culture?

Answer 2

1. Thiamin
2. Riboflavin
3. Niacin
4. Pyroxidine
5. Biotin
6. Pantothenic acid
7. Folic acid
8. B12 required in serum-free media

Question 3

How was vitamin A originally classified?

Answer 3

1. Fat soluble

2. Cured nutritional eye disease

Question 4

How was vitamin B originally classified?

Answer 4

1. Water soluble
2. Found in wheat germ
3. Note: Later notated B1 (heat labile) and B2 (heat stable), and later found as a “complex” and known as essential for all cells due to its cofactor duties for major cellular enzymes.

Question 5

How was vitamin C originally classified?

Answer 5

1. Prevents scurvy

2. Now known as ascorbic acid

Question 6

How was vitamin D originally classified?

Answer 6

1. Prevents rickets

2. Second fat soluble vitamin, but stable to O2 whereas A is not

Question 7

How was vitamin K originally classified?

Answer 7

Koagulation factor

Question 8

Describe the structure of ascorbic acid.

Answer 8

Derivative of glucose with carbonyl group and diethenol as a substituent on a carbon.

Question 9

Vitamin C is essential to what living things and why?

Answer 9

Humans, non-human primates, and guinea pigs because they have lost a key enzyme in the synthetic pathway therefore rendering vitamin C necessary to be obtained via diet.

Question 10

List four enzymatic reactions for which vitamin C is a cofactor.

Answer 10

1. Hydroxylation of proline and lysine in procollagen (scurvy is a deficiency in collagen leading to bleeding gums and hemorrhages and can be prevented with diet)
2. Dopamine –> norepinephrine
3. Synthesis of corticosteroids (concentrated in adrenal glands and increases during stress)
4. Role with cytochrome P450 enzymes (synthesis of bile acids and detox of drugs)

Question 11

List 3 non-enzymatic roles of vitamin C.

Answer 11

1. anti-oxidant and free radical scavenger
2. enhances absorption of iron
3. protects vitamins A, E, and some B vitamins by sparing them.

Question 12

Vitamin B’s are key parts of coenzymes that participate in what reactions?

Answer 12

Intermediate metabolism