General Characteristics of Vitamins ㅡ Water-Soluble Vitamins: The B Vitamins

Question 1

A ___________ is an organic compound, essential in small amounts for the proper functioning of the human body, that must be obtained from dietary sources because
the body cannot synthesize it.

Answer 1

vitamin

Question 2

____________________ function as coenzymes for
a number of important biochemical reactions in humans, animals, and microorganisms.

Answer 2

Water-soluble vitamins

Question 3

__________________ generally do not function as coenzymes in humans and animals and are rarely utilized in any manner by microorganisms.

Answer 3

Fat-soluble vitamins

Question 4

Water-Soluble Vitamins

Answer 4

Vitamin C
Thiamin
Riboflavin
Niacin
Pantothenic acid
Vitamin B6
Biotin
Folate
Vitamin B12

Question 5

Fat-Soluble Vitamins

Answer 5

Vitamin A
Vitamin D
Vitamin E
Vitamin K

Question 6

Vitamin C’s biosynthesis involves ________, an acid derivative of the monosaccharide L-gulose.

Answer 6

L-gulonic acid

Question 7

The most completely characterized role of ___________ is its function as a cosubstrate in the formation of the structural protein collagen which makes up much of the skin, ligaments, and tendons and also serves as the
matrix on which bone and teeth are formed.

Answer 7

vitamin C

Question 8

An intake of _________ of vitamin C saturates all body tissues with the compound.

Answer 8

100 mg/day

Question 9

All of the ___________ serve as precursors for enzyme cofactors

Answer 9

B vitamins

Question 10

The currently preferred names for the B vitamins (alternative names in parentheses) are:

Answer 10

1. Thiamin (vitamin B1)
2. Ribofl avin (vitamin B2)
3. Niacin (nicotinic acid, nicotinamide, vitamin B3)
4. Pantothenic acid (vitamin B5)
5. Vitamin B6 (pyridoxine, pyridoxal, pyridoxamine)
6. Biotin (vitamin B7)
7. Folate (folic acid, vitamin B9)
8. Vitamin B12 (cobalamin)

Question 11

__________’s structure consists of a central carbon atom to which is attached a six-membered heterocylic amine and a five-membered thiazole (sulfurnitrogen) ring system.

Answer 11

“Free” thiamin

Question 12

The coenzyme form of thiamin is called _____________________, a molecule in which a diphosphate group has been attached to the side chain.

Answer 12

thiamin pyrophosphate (TPP)

Question 13

__________ was once called the “yellow vitamin” because of its color.

Answer 13

Riboflavin

Question 14

Two important riboflavin-based coenzymes exist:

Answer 14

flavin adenine dinucleotide (FAD)
flavin mononucleotide (FMN)

Question 15

Niacin occurs in food in two different, but similar, forms:

Answer 15

nicotinic acid
nicotinamide

Question 16

The name pantothenic acid is based on the Greek word “____________,” which means “from everywhere.”

Answer 16

pantothen

Question 17

___________, one of the most used of all vitamin B coenzymes, contains pantothenic acid as part of its structure.

Answer 17

Coenzyme A (CoA)

Question 18

Vitamin B6 is a collective term for three related compounds: ___________ (found in foods of plant origin) and ___________ and _______________ (found in foods of animal origin).

Answer 18

pyridoxine
pyridoxal
pyridoxamine

Question 19

__________ is unique among the B vitamins in that it can be obtained both from dietary intake and also via biotin-producing bacteria (microbiota, hence the name biotin) present in the human large intestine.

Answer 19

Biotin

Question 20

The active coenzyme form of folate, which is known as ______________, has only one glutamate, and four hydrogen atoms have been added to the double-ring nitrogen system.

Answer 20

tetrahydrofolate (THF)

Question 20

In food, about 90% of the folate molecules have three or more glutamate residues present; such molecules are called ______________.

Answer 20

polyglutamates

Question 21

The name ____________ comes from the fact that an atom of the metal cobalt and numerous amine groups are present in the structure of vitamin B12, which is by
far the most complex of all vitamin structures in that it is the only vitamin that contains a metal atom.

Answer 21

cobalamin