Biochemistry Ch 4. Carbohydrate Structure and Function

Question 1

Carbohydrates

Answer 1

Organized by their number of carbon atoms and functional groups, common names are also frequently used when referring to sugars such as glucose, fructose, and galactose, three carbon sugars are trioses, four carbon sugars are tetroses, and so on, nomenclature of all sugars is based on the D and L forms of glyceraldehyde, sugars with the highest numbered chiral carbon with the -OH on the right are D-sugars and those with -OH on the left are L-sugars

Question 2

Aldoses

Answer 2

Sugars with aldehydes as their most oxidized group

Question 3

Ketoses

Answer 3

Sugars with kenos as their most oxidized group

Question 4

Sugar enantiomers

Answer 4

D and L forms of the same sugar

Question 5

Diastereomers

Answer 5

Nonsuperimposable configurations of molecules with similar connectivity, differ at at least one but not all chiral carbons, include epimers and anomers

Question 6

Epimers

Answer 6

A subtype of diastereomers that differ at exactly one chiral carbon

Question 7

Anomers

Answer 7

A subtype of epimers that differ at the anomeric carbon

Question 8

Cyclization

Answer 8

Describes the ring formation of carbohydrates from their straight chain form, when the ring forms, the anomeric carbon can take on either an alpha or beta conformation

Question 9

Anomic carbon

Answer 9

The new chiral center formed in ring closure, it was the carbon containing the carbonyl in the straight chain form

Question 10

Alpha-anomers

Answer 10

Have the -OH on the anomeric carbon trans to the free -CH2OH group

Question 11

Beta-anomers

Answer 11

Have the -OH on the anomeric carbon cis to the free -CH2OH group

Question 12

Haworth projections

Answer 12

Provide a good way to represent three-dimensional structure

Question 13

Mutarotation

Answer 13

When cyclic compounds shift from one anomeric from to another with the straight chain form as an intermediate

Question 14

Monosaccharides

Answer 14

Single carbohydrate units with glucose as the most commonly observed monomer, can undergo three main reactions: redox, esterification, and glycoside formation

Question 15

Aldose redox

Answer 15

Can be oxidized to aldonic acids and reduced to alditols

Question 16

Tollen’s or Benedict’s reagents

Answer 16

Can detect sugars that can be oxidized (reducing sugars/agents)

Question 17

Deoxy sugars

Answer 17

Sugars with an -H replacing an -OH group

Question 18

Esterification of sugars

Answer 18

Sugars can react with carboxylic acids and their derivatives, forming esters

Question 19

Phosphorylation of sugars

Answer 19

A similar reaction to esterification in which a phosphate ester is formed by transferring a phosphate group from ATP onto a sugar

Question 20

Glycoside formation

Answer 20

The basis for building complex carbohydrates and requires the anomeric carbon to link to another sugar

Question 21

Disaccharides

Answer 21

Form as result of glycosidic bonding between two monosaccharides subunits, common disaccharides include sucrose, lactose, and maltose

Question 22

Polysaccharides

Answer 22

Form by repeated monosaccharide or polysaccharide glycosidic bonding

Question 23

Cellulose

Answer 23

Main structural component for plant cell walls and is a main source of fiber in the human diet

Question 24

Starches

Answer 24

includes amylose and amylopectin, function as a main energy storage form for plants

Question 25

Glycogen

Answer 25

Functions as a main energy storage form for animals