Carbohydrate Structure & Function

Question 1

How are monosaccharides named?

Answer 1

Tri, tetr -oses

Question 2

Aldose

Answer 2

Cars with an aldehyde group as their most oxidized functional group

Question 3

Ketose

Answer 3

Carbs with ketone as most oxidized functional group

Question 4

Glyceradehyde

Answer 4

Simplest aldotriose

Question 5

Dihydroxyacetone

Answer 5

Simplest ketotriose

Question 6

Fructose

Answer 6

hexose

Same a glucose but ketone group at C2

Question 7

Glucose

Answer 7

Like the middle finger

Question 8

Galactose

Answer 8

Glucose, switch at C4

Question 9

Mannose

Answer 9

Glucose, switch at C2

Question 10

What are the two absolute configurations of the carbs called?

Answer 10

D & L

Question 11

Number of stereoisomers with common backbone is

Answer 11

2^n

n=number of chiral carbons in the molecule

Question 12

Can (-) or (+) rotation be determined from D orL

Answer 12

No, must be determined experimentally

Question 13

D-sugars have hydroxide of highest chiral centers on?

Answer 13

Right side

Question 14

L- sugars have hydroxide of higher chiral centers on?

Answer 14

Left side

Question 15

Diastereomers

Answer 15

Two sugars in the same family that don’t mirror each other or are identical

Question 16

Epimer

Answer 16

Subtype of diastereomer that differ in configuration at one chiral center

Question 17

What is a hydroxyl group used as?

Answer 17

Nucleophile

Question 18

What is the carbonyl group used as?

Answer 18

Electrophile

Question 19

Cyclic hemiacetal

Answer 19

Intramolecular conversion from aldoes

Question 20

Cyclic hemicketals

Answer 20

Intramolecular conversion from ketose

Question 21

Six-membered rings

Answer 21

Pyranose

Question 22

Five-membered rings

Answer 22

Furanose

Question 23

Anomeric carbon

Answer 23

Carbonyl carbon attacked by hydroxyl group to form a chiral carbon attached to oxygen

Question 24

Anomer

Answer 24

a/B difference at anomeric carbon

Question 25

a-anomer

Answer 25

Has -OH group of C1 trans to CH2OH (axial down)

Question 26

B-anomer

Answer 26

Has-OH group of C1 cis to CH2OH (equitorial up)

Question 27

How are hemiacetals/hemiketals formed?

Answer 27

2nd to last -OH group attacks C1 carbonyl

Question 28

Right sideded on Fischer points on Haworth?

Answer 28

Down

Question 29

Mutarotation

Answer 29

Spontaneous change of conformation about C1
Occurs more rapidly when catalyzed with an acid or base
All other configurations stay the same

Question 30

Which anomer is favored?

Answer 30

Beta- equitorial

Question 31

What causes mutorotation?

Answer 31

Addition of water will cause a mixture of the sugars

Question 32

Oxidized carboxylic acid

Answer 32

Aldonic acid

Question 33

A aldose/hemicacetal is considered what because it an be oxidized?

Answer 33

Reducing agent, reducing sugar

Question 34

Lactone

Answer 34

Oxidation of aldose in ring from- cyclic ester with conbonyl carbon at anomeric carbon

Question 35

Tollen’s reagent

Answer 35

Oxidizing agent (it becomes reduced)
Aldehydes reduce Ag+ to metallic silver

Question 36

Benedict’s reagent

Answer 36

Oxidizing agent (it becomes reduced)
Aldehyde reduces to create Cu2O

Question 37

Nitric acid

Answer 37

Powerful oxidizing agent

Oxidizes aldehyde & hydroxyls to carboxylic acids

Question 38

What would be used to specifically test for glucose?

Answer 38

Glucose oxidase

Question 39

Enol

Answer 39

Ketone picks up a hydrogen while the double ond is moved between two adjacent groups- has a double bond and an alcohol group

Question 40

Tautomerization

Answer 40

Rearrangement of bonds in a compound, moving a hydrogen and forming a double bond

Question 41

When do ketones form aldoses

Answer 41

When they tautomerize under basic conditions to form enol-form

Question 42

Alditol

Answer 42

Aldehyde group of aldose reduced to alchol

Question 43

Deoxy sugar

Answer 43

Has a hydrogen that replaces a hydroxyl on the sugar