Carbohydrates

Question 1

What is the general formula of carbohydrates?

Answer 1

Cn(H2O)n

Question 2

In hyaluronic acid how is N-acetyl-D-glucosamine linked to D-glucuronate?

Answer 2

by a β(1 → 4) glycosidic bond

Question 3

In hyaluronic acid how is D-glucuronate linked to N-acetyl-D-glucosamine?

Answer 3

by a β(1 → 3) glycosidic bond

Question 4

What classification of carbohydrates has 3-10 units of sugar?

Answer 4

Oligosaccharides

Question 5

What carbohydrates cannot be hydrolyzed to a simpler compound?

Answer 5

Monosaccharides

Question 6

Monosaccharides that contain an aldehyde group (-CHO).

Answer 6

Aldoses

Question 7

Monosaccharides that contain a ketone group (-C=O).

Answer 7

Ketoses

Question 8

Two-dimensional representations showing the configuration of a tetrahedral stereocenter.

Answer 8

Fischer Projection Formula

Question 9

Molisch test gives a purple-colored ring at the junction. This test is specifically for what type of monosaccharides?

Answer 9

pentoses and hexoses

Question 10

What carbohydrates are associated with crustacean shells?

Answer 10

Chitin

Question 11

An unknown solution gives a reddish-orange color when tested in an iodine solution. What could be indicated in this result?

Answer 11

no presence of starch in the unknown solution

Question 12

An unknown solution shows a green color when tested in benedict’s test. This result shows ___________.

Answer 12

traces of reducing sugar

Question 13

OH group is replaced with _____ in amino sugar formation.

Answer 13

amino group (NH2)

Question 14

What is the arbitrary assignment (D or L) to the enantiomer if the -OH on the penultimate carbon is on the right in a Fischer projection?

Answer 14

(D-) Dextrorotatory-glyceraldehyde

Question 15

What is the arbitrary assignment (D or L) to the enantiomer if the -OH on the penultimate carbon is on the left in a Fischer projection?

Answer 15

(L-) Levorotatory-glyceraldehyde

Question 16

A component of many polysaccharides, including connective tissue such as cartilage.

Answer 16

N-Acetyl-D-glucosamine (derivative of D-glucosamine)

Question 17

What reacts with carbonyl groups (aldehydes and ketones) to form hemiacetals?

Answer 17

alcohol

Question 18

The common way to represent the cyclic structure of monosaccharides.

Answer 18

Haworth projections

Question 19

A new carbon stereocenter created in the formation of the cyclic structure.

Answer 19

Anomeric carbon

Question 20

Stereoisomers that differ in a configuration only at the anomeric carbon.

Answer 20

Anomers

Question 21

A six-membered hemiacetal ring.

Answer 21

Pyran

Question 22

A five-membered hemiacetal ring.

Answer 22

Furan

Question 23

What are the four essential monosaccharides?

Answer 23

1. Glucose
2. Galactose
3. Fructose
4. Ribose

Question 24

What is the sweetest tasting of all sugars?

Answer 24

Fructose

Question 25

What is the most abundant monosaccharide?

Answer 25

Glucose

Question 26

True or False. | Ribose has a six-membered cyclic form.

Answer 26

False. (It is a five-membered cyclic)

Question 27

Under what conditions can monosaccharides be oxidized to aldaric acids?

Answer 27

Through a strong oxidizing agent

Question 28

Under what conditions can monosaccharides be oxidized to aldonic acids?

Answer 28

Through a weak oxidizing agent

Question 29

Under what conditions can monosaccharides be oxidized to alduronic acids?

Answer 29

Through an enzymatic oxidizing agent

Question 30

An oxidizing agent that can oxidize both ends of a monosaccharide.

Answer 30

Strong oxidizing agent

Question 31

An oxidizing agent that oxidizes the primary alcohol end of an aldose (e.g. glucose).

Answer 31

Enzymatic oxidizing agent

Question 32

What reaction of monosaccharides happens when a carbonyl group is reduced to a hydroxyl group?

Answer 32

Reduction to sugar alcohols (alditol)

Question 33

It reacts with sugars to form glycosides

Answer 33

alcohol

Question 34

What glycoside is produced from glucose?

Answer 34

Glucoside

Question 35

The bond that joins a simple sugar unit (mono) to another group.

Answer 35

Glycosidic bond

Question 36

What are the four most common disaccharides?

Answer 36

1. Sucrose 2. Lactose 3. Maltose 4. Cellobiose

Question 37

Disaccharides that have β(1→4) glycosidic linkage.

Answer 37

Lactose and cellobiose

Question 38

A type of disaccharide that has a(1→4) glycosidic linkage.

Answer 38

Maltose

Question 39

A type of oligosaccharide that consists of (1) galactose, (1) glucose, and (1) fructose units.

Answer 39

Raffinose

Question 40

A type of oligosaccharide that consists of (2) galactose, (1) glucose, and (1) fructose units.

Answer 40

Stachyose

Question 41

What determines blood type A in the ABO blood typing system?

Answer 41

The presence of N-acetyl-D-galactosamine antigen only

Question 42

What are the four most common polysaccharides?

Answer 42

1. Starch 2. Glycogen 3. Cellulose 4. Chitin

Question 43

A polysaccharide that is used as storage in plants.

Answer 43

Starch

Question 44

True or False. | Polysaccharides are not sweet and do not show positive tests with Tollen's and Benedict's solutions.

Answer 44

True

Question 45

What do you call the formation of glycogen?

Answer 45

Glycogenesis

Question 46

What do you call the decomposition of glycogen?

Answer 46

Glycogenosis

Question 47

It consists of as many as 10,000 D-glucose units linearly linked by α(1 → 4) glycosidic bonds and there are branches every 24-30 units via α(1 → 6) glycosidic bonds.

Answer 47

Amylopectin (unbranched starch)

Question 48

It consists of as many as 4000 D-glucose units linearly linked by α(1 → 4) glycosidic bonds.

Answer 48

Amylose (branched starch)

Question 49

A polysaccharide that consists of 1 million glucose units.

Answer 49

Glycogen

Question 50

A polysaccharide that consists of 5000 glucose units.

Answer 50

Cellulose

Question 51

True or False. | Humans have cellulase to hydrolyze the β(1→4) linkages in cellulose.

Answer 51

False. | Humans do not have cellulase (enzyme), so they cannot digest cellulose.

Question 52

Polysaccharides with repeating disaccharide units containing amino sugar and sugar with a negative charge due to a sulfate or carboxyl group.

Answer 52

Acidic polysaccharide

Question 53

An acidic polysaccharide with 15-90 disaccharide residues per chain (a blood anticoagulant)

Answer 53

Heparin

Question 54

A qualitative test of color reaction specific for ketoses.

Answer 54

Seliwanoff's Test

Question 55

What is the purpose of Barfoed's test?

Answer 55

To detect the presence of monosaccharide (reducing) sugars in solution or to distinguish disaccharides to monosaccharides.