Vitamin B3

Question 1

What is another name for niacin?

Answer 1

Nicotinic acid

Question 2

What is niacin also known as?

Answer 2

Pellagra preventive (P.P.) factor of Goldberger

Question 3

Which coenzymes are derived from niacin?

Answer 3

NAD+ and NADP+

Question 4

Which amino acid can synthesize niacin coenzymes?

Answer 4

Tryptophan

Question 5

What disease is caused by niacin deficiency?

Answer 5

Pellagra

Question 6

What does pellagra mean in Italian?

Answer 6

Rough skin

Question 7

Who identified the dietary cause of pellagra?

Answer 7

Goldberger

Question 8

What experiment did Goldberger conduct?

Answer 8

Gave pellagrous diet to convicts for one year

Question 9

What foods were included in the pellagrous diet?

Answer 9

Corn meal, corn starch, rice, sweet potato, pork fat

Question 10

How many subjects developed pellagra in Goldberger’s experiment?

Answer 10

More than half

Question 11

What cured pellagra in the experiment?

Answer 11

Dried meat or liver

Question 12

When was this pellagra experiment conducted?

Answer 12

1928

Question 13

How was nicotinic acid originally produced?

Answer 13

By oxidation of nicotine in tobacco leaves

Question 14

Why was the term ‘niacin’ coined?

Answer 14

To avoid confusion with nicotine and show its vitamin role

Question 15

Are niacin and nicotinic acid the same?

Answer 15

Yes

Question 16

What is the structure of niacin?

Answer 16

Pyridine 3-carboxylic acid

Question 17

What is the amide form of niacin?

Answer 17

Niacinamide or nicotinamide

Question 18

Which three dietary sources contribute to NAD+/NADP+ synthesis?

Answer 18

Nicotinamide, niacin, tryptophan

Question 19

What happens to nicotinamide in the body?

Answer 19

Deaminated to niacin

Question 20

What does tryptophan first form in niacin synthesis?

Answer 20

Quinolinate

Question 21

What is the intermediate formed after quinolinate?

Answer 21

Nicotinate mononucleotide

Question 22

What is the final product of niacin synthesis?

Answer 22

NAD+ and NADP+

Question 23

How much tryptophan equals 1 mg of niacin?

Answer 23

60 mg

Question 24

What does phosphoribosyl pyrophosphate provide in NAD+ synthesis?

Answer 24

Ribose phosphate

Question 25

What does ATP provide in NAD+ synthesis?

Answer 25

AMP moiety

Question 26

What does glutamine donate in NAD+ synthesis?

Answer 26

Amide group

Question 27

What is the charge on the nitrogen of nicotinamide in coenzymes?

Answer 27

Positive charge

Question 28

Why is the nitrogen positively charged in coenzymes?

Answer 28

Extra bond makes nitrogen quaternary

Question 29

How is excess nicotinamide excreted?

Answer 29

As N-methyl nicotinamide in urine

Question 30

What do NAD+ and NADP+ participate in?

Answer 30

Oxidation-reduction reactions

Question 31

What do NAD+ and NADP+ accept?

Answer 31

Hydride ion (H?)

Question 32

What part of nicotinamide ring is involved in the redox reaction?

Answer 32

Nitrogen and fourth carbon atom

Question 33

What happens to the second hydrogen during redox reaction?

Answer 33

Released as H+ into medium

Question 34

How is NADH converted back to NAD+?

Answer 34

By oxidation

Question 35

Does NADP+ function similarly to NAD+?

Answer 35

Yes

Question 36

How many enzymes use NAD+/NADP+?

Answer 36

About 40 oxidoreductases

Question 37

What does niacin inhibit in adipose tissue?

Answer 37

Lipolysis

Question 38

What happens to circulating free fatty acids with niacin?

Answer 38

They decrease

Question 39

What happens to triacylglycerol synthesis with niacin?

Answer 39

It decreases

Question 40

What serum components are lowered by niacin?

Answer 40

LDL, VLDL, triacylglycerol, cholesterol

Question 41

What condition is niacin used to treat?

Answer 41

Hyperlipoproteinemia type IIb

Question 42

What does megadose niacin deplete in muscles?

Answer 42

Glycogen and fat reserves

Question 43

What can increase with prolonged niacin use?

Answer 43

Glucose and uric acid levels

Question 44

What may elevated serum enzymes suggest after niacin use?

Answer 44

Liver damage

Question 45

What are harmful effects of prolonged high-dose niacin?

Answer 45

Muscle depletion, high glucose, high uric acid, liver damage