Carbohydrate Structure and Function

Question 1

Aldoses

Answer 1

Carbohydrates that contain an aldehyde group as their most oxidized group

Question 2

Ketoses

Answer 2

Carbohydrates that contain a ketone group as their most oxidized functional group

Question 3

Glyceraldehyde

Answer 3

the simplest aldose
carbonyl carbon is most oxidized, always lowest number
aldehyde carbon can participate in glycosidic linkages

Question 4

Draw a D-Fructose structure.

Answer 4

Question 5

Draw a D-Glucose structure.

Answer 5

Question 6

D-galactose

Answer 6

Question 7

D-mannose

Answer 7

Question 8

D vs. L

Answer 8

D sugars have the hydroxide of their highest numbered chiral center on the right and all L sugars have that hydroxide on the left

Question 9

Optical isomers or stereoisomers

Answer 9

Compounds that have the same chemical formula, but differ from spatial arrangement of their component atoms

Question 10

Enantiomers

Answer 10

Stereoisomers that are nonidentical, nonsuperimposable mirror images of each other

Question 11

Number of stereoisomers with common backbone

Answer 11

Question 12

Diastereomers

Answer 12

Not identical and not mirror images of one another

Question 13

Epimers

Answer 13

Diastereomers that differ in configuration at exactly one chiral center only

Question 14

Hydroxyl group of monosaccharide

Answer 14

serves as a nucleophile

Question 15

Carbonyl group of monosaccharide

Answer 15

serves as an electrophile

Question 16

Anomeric Carbon

Answer 16

carbonyl group becomes chiral and forms a ring in the process

Question 17

alpha anomer

Answer 17

Alpha axial
fishes down in the sea, Birds in the air

Question 18

Beta Anomer

Answer 18

fishes down in the sea, Birds in the air

Question 19

Mutarotation

Answer 19

spontaneous change of configuration on C-1 to form alpha or beta anomer and occurs more rapidly when the reaction is catalyzed with an acid or base; interconversion between anomers of a compound

Question 20

Aldonic Acids

Answer 20

oxidation of aldolases during open-chain aldehyde form

Question 21

Since aldolases can be oxidized, they are called ____

Answer 21

reducing agents

Question 22

Any monosaccharides with a hemiacetal ring is considered ____

Answer 22

reducing sugar

Question 23

Lactone

Answer 23

when the aldose is in ring form and gets oxidized; it is a cyclic ester with a carbonyl group persisting on the anomeric carbon

Question 24

Tollen’s reagent

Answer 24

uses silver nitrate as an oxidizing agent;
positive test results in aldehydes reducing Ag+ to metallic silver

Question 25

Benedict’s Reagent

Answer 25

aldehyde group of an aldose is readily oxidized, indicated by red precipitate of cupric oxide

Question 26

Tautomerization

Answer 26

refers to the rearrangement of bonds in a compound, usually by moving a hydrogen and forming a double bond

Question 27

esterification

Answer 27

reaction by which a hydroxyl group reacts with either a carboxylic acid or carboxylic derivative to form an ester

Question 28

glycoside formation

Answer 28

reaction between an alcohol and a hemiacetal or hemiketal group on a sugar to yield an alkoxy group

Question 29

From a metabolic standpoint, does it make sense for carbohydrates to get oxidized or reduced? Purpose?

Answer 29

Oxidized because they will be able to reduce other groups. Aerobic metabolism requires reduced forms of electron carriers to facilitate processes such as oxidative phosphorylation

Question 30

Which of the two forms of starch is more soluble in the solution? Why?

Answer 30

amylopectin is more soluble in solution than amylose because of its branched structure; it decreases intermolecular bonding between polysaccharide polymers and increases interaction with the surrounding solution

Question 31

Between glycogen and amylopectin, which one have a higher rate of enzyme activity from enzymes that cleave side branches? Why?

Answer 31

glycogen has higher rate of enzymatic branch cleavage because it contains more branching than amylopectin

Question 32

beta-amylase

Answer 32

cleaves at the nonreducing end of the polymer to yield maltose only

Question 33

alpha-amylase

Answer 33

cleaves anywhere along the chain to yield polysaccharides, maltose, and glucose

Question 34

debranching enzyme

Answer 34

removes oligosaccharides from a branch in glycogen or starch

Question 35

glycogen phosphorylase

Answer 35

yields glucose 1- phosphate

Question 36

amylose and amylopectin

Answer 36

both are starches
alpha 1,4 and alpha 1,6 linkages

Question 37

cellulose uses what linkage?

Answer 37

beta-1,4 linkage

Question 38

what linkage cannot be cleaved in the human body?

Answer 38

b-glycosidic linkage

Question 39

glycogen

Answer 39

more alpha 1,6 linkages than starch, highly branched

Question 40

forming ring carbohydrate

Answer 40

down right up lefting

Question 41

Are we enzymatically programmed to digest L or D sugars?

Answer 41

D sugars