Monosaccharides

Question 1

Definition of carbohydrates

Answer 1

Organic compounds characterized by 3 features:
1. Contain CHO
2. Poly-hydroxyl: more than one OH group
3. Contain free active carbonyl group: aldehyde or ketone

Question 2

Why we study CHO

Answer 2

CHO is the primary source for production of energy for tissues (brain,muscles and erythrocytes)

Question 3

Classification of carbohydrates

Answer 3

Classified according to the number of sugar units Into:
Monosaccharides: 1 sugar unit
Disaccharides: 2 sugar units
Oligosaccharides: 3-10 sugar units
Polysaccharides: more than 10 sugar units

Question 4

Monosaccharides definition

Answer 4

Simplest sugar units that cannot be hydrolyzed into smaller units

Question 5

Monosaccharides classification

Answer 5

Classified according to
1. Number of carbons
Trioses: 3 carbons
Tetroses: 4 carbons
Pentoses: 5 carbons
Hexoses: 6 carbons
Haptoses: 7 carbons
2. The active sugar carbonyl group:
Aldehyde (aldoses)
Ketone (ketoses)

Question 6

Monosaccharides classification table

Answer 6

Aldose(aldosugar):
Triose: glyceraldehyde
Tetrose: erythrose
Pentose: ribose, xylose
Hexose: glucose, galactose, mannose
Haptose: glucohaptose

Ketose(ketosugar):
Triose: dihydroxy acetone
Tetrose: erythrulose
Pentose: ribulose, xylulose
Hexose: fructose
Haptose: sedoheptulose

Question 7

Monosaccharides of biological importance

Answer 7

Glucose(dextrose)(grape sugar)
Galactose
Mannose
Fructose
Pentoses(ribose)

Question 8

Glucose

Answer 8

Also called dextrose and grape sugar
1. The principle famous sugar in blood
2. It is the primary source for production of energy for tissues (brain and erythrocytes)
3. Ingested carbohydrates are absorbed in the form of glucose
4.it can be converted into other sugars
- galactose and lactose: in mammary gland
- fructose: in seminal plasma
- ribose: in all tissues except skeletal muscle
- glycogen: in liver and skeletal muscle

Question 9

Galactose

Answer 9

Enters in the formation of:
1. Lactose(milk sugar): in mammary gland
2. Galactolipid and glycoproteins

Question 10

Mannose

Answer 10

Enters in the formation of glycoproteins

Question 11

Fructose

Answer 11

Fruit sugar
Enters in the formation of:
Sucrose (disaccharides)
Inulin (polysaccharide)
It is the sugar of seminal plasma (sperms utilize fructose for energy production)

Question 12

Pentoses

Answer 12

Ribose
Enter in the formation of:
1. Nucleic acids: RNA and DNA
2. High energy phosphate compounds: ATP
3. Co-enzymes: NAD and NADP
4. Second messenger for hormonal action: cAMP
5. Vitamins: riboflavin