Carbohydrates

Question 1

A polyhydroxyaldehyde or polyhydroxyketone, or a substance that gives these compounds on hydrolysis.

Answer 1

Carbohydrate

Question 2

A carbohydrate that cannot be
hydrolyzed to a simpler carbohydrate.

Answer 2

Monosaccharide

Question 3

Monosaccharides have the general formula _______, where n varies from 3 to 7.

Answer 3

CnH2nOn

Question 4

A monosaccharide containing an aldehyde group.

Answer 4

Aldose

Question 5

A monosaccharide containing a ketone group.

Answer 5

Ketose

Question 6

The suffix _____ indicates that a molecule is a carbohydrate.

Answer 6

-ose

Question 7

The prefixes _________ and so forth indicate the number of carbon atoms in the chain.

Answer 7

tri-, tetra-, penta-,

Question 8

There are only two trioses:
1. ________
2. ________

Answer 8

1. Glyceraldehyde
2. Dihydroxyacetone

Question 9

____________, the simplest aldose, contains one stereocenter and exists as a pair of enantiomers.

Answer 9

Glyceraldehyde

Question 10

A two-dimensional representation for showing the configuration of tetrahedral stereocenters.

Answer 10

Fischer Projection

Question 11

• _________ lines represent bonds projecting forward from the stereocenter.

• _________ lines represent bonds projecting to the rear.

• Only the __________ is in the plane.

Answer 11

Horizontal

Vertical

Stereocenter

Question 12

In ______, ________ made the arbitrary assignments of D- and L- to the enantiomers of glyceraldehyde.

Answer 12

1891

Emil Fischer

Question 13

The –OH on its penultimate carbon is on the right in a Fischer projection.

Answer 13

D-monosaccharide

Question 14

–OH on its penultimate carbon is on the left in a the Fischer projection.

Answer 14

L-monosaccharide

Question 15

_______, _______, and ______ are all hexoses found prominently in our metabolism.

Answer 15

D-Glucose

D-galactose

D-fructose

Question 16

________ is normally found in human blood at concentrations of 65 to 110 mg/dL.

Answer 16

D-Glucose

Question 17

_______ is part of the disaccharide lactose.

Answer 17

D-Galactose

Question 18

_______ is twice as sweet as table sugar.

Answer 18

D-Fructose

Question 19

Aldehydes and ketones react with alcohols to form _________.

Answer 19

hemiacetals

Question 20

________ form readily when hydroxyl and carbonyl groups are part of the same molecule and their interaction can form a five- or six-membered ring.

Answer 20

Cyclic hemiacetals

Question 21

A ________ is represented as a planar ring, lying roughly perpendicular to the plane of the paper.

Answer 21

five- or six-membered cyclic hemiacetal

Question 22

The new carbon stereocenter created in forming the cyclic structure is called the __________.

Answer 22

anomeric carbon

Question 23

Stereoisomers that differ in configuration only at the anomeric carbon are called _________.

Answer 23

anomers

Question 24

The anomeric carbon of an aldose is _______; that of most common ketoses is _______.

Answer 24

carbon 1

carbon 2

Question 25

______ means that the –OH on the anomeric carbon is on the same side of the ring as the terminal –CH2OH

Answer 25

β (beta)

Question 26

_____ means that the –OH on the anomeric carbon is on the side of the ring opposite from the terminal –CH2OH.

Answer 26

α (alpha)

Question 27

A six-membered hemiacetal ring is called a ________.

Answer 27

pyranose

Question 28

A five-membered hemiacetal ring is called a ________.

Answer 28

furanose

Question 29

_______ also form cyclic hemiacetals.

Answer 29

Aldopentoses

Question 30

The most prevalent forms of D-ribose and other pentoses in the biological world are _______.

Answer 30

furanoses

Question 31

The prefix ______ means “without oxygen.”

Answer 31

“deoxy”

Question 32

The change in specific rotation that accompanies the equilibration of α- and β-anomers in aqueous solution.

Answer 32

Mutarotation

Question 33

Treatment of a monosaccharide, all of which exist almost exclusively in cyclic hemiacetal forms, with an alcohol gives an _____.

Answer 33

acetal

Question 34

A cyclic acetal derived from a monosaccharide is called a ______.

Answer 34

glycoside

Question 35

The bond from the anomeric carbon to the –OR group is called a ______.

Answer 35

glycosidic bond

Question 36

Mutarotation is not possible for a glycoside because an ______, unlike a ______, is not in equilibrium with the open-chain carbonyl-containing compound.

Answer 36

acetal hemiacetal

Question 37

Glycosides are stable in __________, but like other acetals, are hydrolyzed in aqueous acid to an __________.

Answer 37

water and aqueous base alcohol and a monosaccharide

Question 38

Glycosides are named by listing the ________ group bonded to oxygen followed by the name of the _______ in which the ending -e is replaced by -ide.

Answer 38

alkyl or aryl carbohydrate

Question 39

The carbonyl group of a monosaccharide can be reduced to an hydroxyl group by a variety of reducing agents, including _______ in the presence of a transition metal catalyst (H2/Pt).

Answer 39

NaBH4 and H2

Question 40

The reduction product of the carbonyl group of a monosaccharide to a hydroxyl group is called an ______.

Answer 40

alditol

Question 41

Alditols are named by changing the suffix ______ to -itol.

Answer 41

-ose -itol

Question 42

_______ is found in the plant world in many berries and in cherries, plums, pears, apples, seaweed, and algae.

Answer 42

Sorbitol

Question 43

Sorbitol is about ______ as sweet as sucrose (table sugar) and is used in the manufacture of candies and as a sugar substitute for diabetics.

Answer 43

60 percent

Question 44

These three alditols are also common in the biological world:

Answer 44

1. Erythritol 2. Mannitol 3. Xylitol

Question 45

The aldehyde group of an aldose is oxidized under basic conditions to a ________.

Answer 45

carboxylate anion

Question 46

The oxidation product of an aldehyde group of an aldose to a carboxylate anion is called an _______.

Answer 46

aldonic acid

Question 47

A carbohydrate that reacts with an oxidizing agent to form an aldonic acid is classified as a _______ (it reduces the oxidizing agent).

Answer 47

reducing sugar

Question 48

Enzyme-catalyzed oxidation of the primary alcohol at carbon 6 of a hexose yields a ______.

Answer 48

uronic acid

Question 49

________ is widely distributed in both the plant and animal worlds; an important component of the acidic polysaccharides of connective tissues.

Answer 49

D-Glucuronic acid

Question 50

Table sugar, obtained from the juice of sugar cane and sugar beet.

Answer 50

Sucrose

Question 51

The principal sugar present in milk. • About 5–8% in human milk, 4–5% in cowʼs milk

Answer 51

Lactose

Question 52

From malt, the juice of sprouted barley and other cereal grains.

Answer 52

Maltose

Question 53

A carbohydrate consisting of large numbers of monosaccharide units joined by glycosidic bonds.

Answer 53

Polysaccharide

Question 54

A polymer of D-glucose.

Answer 54

Starch

Question 55

Starch can be separated into _____ and ______.

Answer 55

amylose amylopectin

Question 56

_____ is composed of unbranched chains of up to 4000 D-glucose units joined by a-1,4-glycosidic bonds.

Answer 56

Amylose

Question 57

______ contains chains up to 10,000 D-glucose units also joined by a-1,4-glycosidic bonds. At branch points, new chains of 24 to 30 units are started by a-1,6-glycosidic bonds.

Answer 57

Amylopectin

Question 58

_______ is the energy-reserve carbohydrate for animals.

Answer 58

Glycogen

Question 59

Glycogen is a branched polysaccharide of approximately _______ joined by a-1,4- and a-1,6-glycosidic bonds.

Answer 59

10^6 glucose units

Question 60

The total amount of glycogen in the body of a well- nourished adult human is about _____, divided almost equally between liver and muscle.

Answer 60

350g

Question 61

_______ is a linear polysaccharide of D-glucose units joined by b-1,4-glycosidic bonds.

Answer 61

Cellulose

Question 62

Cellulose has an average molecular weight of _______, corresponding to approximately 2200 glucose units per molecule.

Answer 62

400,000 g/mol

Question 63

Cellulose molecules act like stiff rods and align themselves side by side into well-organized water-insoluble fibers in which their _______ form numerous intermolecular hydrogen bonds.

Answer 63

–OH groups

Question 64

This arrangement of parallel chains in bundles gives cellulose fibers their ________.

Answer 64

high mechanical strength

Question 65

Humans and other animals can not digest cellulose because their digestive systems do not contain _________, enzymes that catalyze the hydrolysis of b-glycosidic bonds.

Answer 65

b-glycosidases

Question 66

_________ have such bacteria (b-glycosidases) in their intestines and can use wood as their principal food.

Answer 66

Termites

Question 67

Humans have only _____; hence, the polysaccharides we use as sources of glucose are starch and glycogen.

Answer 67

a-glucosidases

Question 68

______ is synthesized and stored in mast cells of various tissues, particularly the liver, lungs, and gut.

Answer 68

Heparin

Question 69

The best known and understood of Heparin’s biological functions is its _______.

Answer 69

anticoagulant activity

Question 70

Heparin binds strongly to ________, a plasma protein involved in terminating the clotting process.

Answer 70

antithrombin III