Carbohydrates

Question 1

Most abundant class of biological molecules

Answer 1

Carbohydrates

Question 2

Monosaccharide

Answer 2

Smallest unit of carbohydrate structure
Empirical formula (CH2O)n, where n= 3-9 (5-6 common)

Question 3

Oligosaccharide

Answer 3

Polymers containing 2-20 monosaccharide residues

Question 4

Polysaccharide

Answer 4

Polymers that typically contain more than 20 residues

Question 5

2 types of monosaccharides

Answer 5

Aldoses (aldehydes)

Ketoses (ketones)

Question 6

Epimers

Answer 6

Stereoisomers that differ in configuration at only 1 chiral center

Question 7

Hemiacetal/hemiketal

Answer 7

Structure with hydroxyl group and ether at same carbon

Question 8

2 forms of cyclized rings

Answer 8

Furanose (5-membered)

Pyranose (6-membered)

Question 9

Alpha and beta anomeric positions in D-sugars

Answer 9

Alpha: trans to C6
Beta: cis to C6
L-sugars: switched

Question 10

Sugar phosphates

Answer 10

One of the carbohydrate’s hydroxyl groups is converted to a phosphate ester

Question 11

Deoxy sugars

Answer 11

Hydrogen replaces the hydroxyl in the parent sugar

Question 12

Amino sugars

Answer 12

Amino group replaces a hydroxyl in the parent monosaccharide

Position of amino group is not always obvious, since it isn’t numbered (but often carbon #2)

Question 13

Sugar alcohols

Answer 13

Carbonyl of parent sugar is reduced to an alcohol

Replace -ose with -itol

Question 14

Sugar acids

Answer 14

Either C-1 aldehyde is oxidized to carboxylic acid or primary alcohol (highest carbon number) is oxidized to an acid

Question 15

Disaccharides

Answer 15

Covalent linkage of 2 monosaccharides through a glycosidic bond at the anomeric carbon
Named in order with “free anomeric” sugar last
Glycosidic bonding is indicated using numbers separated by an arrow

Question 16

Reducing sugars

Answer 16

Sugars with an aldehyde or a hemiacetal can be oxidized to an acid and can reduce other ions

Question 17

2 types of polysaccharides

Answer 17

Homoglycans: 1 type of monomer
Heteroglycans: several types of monomers

Question 18

Amylose

Answer 18

Type of starch (storage polysaccharide)
Smaller than amylopectin and glycogen
Alpha- (1 -> 4) glycosidic linkages

Question 19

Amylopectin

Answer 19

Type of starch (storage polysaccharide and polymer of glucose)
Bigger than amylose, but smaller than glycogen
Amylose with alpha- (1 -> 6) branches every ~25 residues

Question 20

Glycogen

Answer 20

Form of storage used in most animals
Main chain is alpha- (1 -> 4)
Alpha- (1 -> 6) linkages every 8-12 residues
Bigger than amylose or amylopectin

Question 21

Cellulose

Answer 21

Linear polymer of glucose
Structural polysaccharide in plants
Unbranched, beta- (1 -> 4) glycosidic bonds
Highly rigid

Question 22

Chitin

Answer 22

Structural polysaccharide in bugs and crustaceans
Linear polymer of N-acetylglucosamine
Beta- (1 -> 4) glycosidic bonds

Question 23

Glycoconjugates

Answer 23

Polysaccharides covalently bound to proteins or peptides

Question 24

Proteoglycans

Answer 24

Complexes of proteins and glycosaminoglycans

High surface area: attract water for connective tissue

Question 25

Glycoproteins

Answer 25

Carbohydrates attached to proteins

Classified as N-linked (asparagine) or O-linked (serine)

Question 26

Peptidoglycans

Answer 26

Polysaccharides linked to small peptides

Found in the cell walls of many types of bacteria: keeps cell in rigid shape by maintaining osmotic balance