Deck 20: Carbohydrates

Question 1

How many acetals are present in the disaccharide shown below?

A)1
B)2
C)3
D)4

Answer 1

B

Question 2

Which Haworth projection represents the $\beta$ anomer of the monosaccharide shown below?

A)
B)
C)
D)

Answer 2

Question 3

What product forms when the compound below is treated with Benedict's reagent?

A)
B)
C)
D)
E)No reaction occurs.

Answer 3

A

Question 4

What product forms when the compound below is treated with Benedict's reagent?

A)
B)
C)
D)

Question 5

The formation of what color in the Benedict's test indicates a reducing sugar is present in solution?

A)blue
B)brick red
C)bright yellow
D)silver

Question 6

Salicin is a naturally occurring, carbohydrate-containing pain reliever. Which statement concerning the functional groups present in salicin is incorrect?

A)Salicin contains an acetal.
B)Salicin contains an alcohol.
C)Salicin contains a hemiacetal.
D)Salicin contains a phenol.

Question 7

What are monosaccharides with a carbonyl group at C1 called?

A)anomers
B)aldoses
C)ketoses
D)alditols

Question 8

Which carbohydrates cannot be converted to simpler compounds by hydrolysis?

A)disaccharides
B)monosaccharides
C)polysaccharides
D)starches

Question 9

What product forms when the compound below is treated with H₂ in the presence of a Pd catalyst?

A)
B)
C)
D)

Question 10

When converting a Fischer projection to a Haworth projection, where are all of the substituents on the right side of the carbon skeleton drawn in the Haworth projection?

A)down
B)up
C)down in an $\alpha$ anomer and up in a $\beta$ anomer
D)down in an $\beta$ anomer and up in a $\alpha$ anomer

Question 11

What is the classification of the compound shown below?

A)an aldohexose
B)a ketohexose
C)an aldopentose
D)a ketopentose

Question 12

The structures of galactose (left)and glucose (right)are shown below. How are the two monosaccharides related?

A)structural isomers
B)stereoisomers
C)enantiomers
D)anomers

Question 13

Disaccharides and polysaccharides contain monosaccharide units joined together by which of the following?

A)hydrogen bonding
B)glycosidic linkages
C)hemiacetal bonds
D)dipole-dipole forces

Question 14

Lactose is present in milk. What type of sugar is lactose?

A)a disaccharide
B)a monosaccharide
C)a polysaccharide
D)a starch

Question 15

Which labeled carbon atom in the structure below is the anomeric carbon?

A)A
B)B
C)C
D)D

Question 16

How many chirality centers are present in the compound shown below?

A)2
B)4
C)5
D)6

Question 17

What is the classification of the compound shown below?

A)a tetraketose
B)a ketotriose
C)a ketotetrose
D)an aldotriose

Question 18

Which monosaccharide is an aldotriose?

A)
B)
C)
D)

Question 19

What is the classification of the compound shown below?

A)L
B)D
C)A sugar this small is not classified as L or D.

Question 20

Which compound is the most soluble in water?

A)CH₂OHCHOHCHOHCHOHCHOHCHO
B)CH₃CH₂CH=CHCH₂CH=CHCH₂CH₂CH₂CH₂CH₂CH₂CH₂COOH
C)CH₃CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₃
D)CH₃CH₂CH₂CH₂CH₂CH₂CH₂CH₂OH

Question 21

The simplest aldose is commonly called glyceraldehyde, although its IUPAC name is 2, 3-dihydroxypropanal. What is the structure of this compound?

A)
B)
C)
D)

Question 22

What is the most common type of starch molecules?

A)cellulose
B)amylose
C)amylopectin
D)glycogen

Question 23

What is the structure of amylopectin?

A)unbranched skeleton of glucose molecules joined by 1 $\rightarrow$ 4- $\alpha$ -glycoside linkages
B)branched skeleton of glucose molecules joined by 1 $\rightarrow$ 4- $\alpha$ -glycoside linkages
C)unbranched skeleton of glucose molecules joined by 1 $\rightarrow$ 4- $\beta$ -glycoside linkages
D)branched skeleton of glucose molecules joined by 1 $\rightarrow$ 4- $\beta$ -glycoside linkages

Question 24

Which is not a naturally-occurring polysaccharide?

A)starch
B)cellulose
C)maltose
D)glycogen

Question 25

What is the difference between the disaccharides lactose and maltose?

A)Lactose contains two glucose units, while maltose contains two galactose units.
B)The two monosaccharides in lactose are joined by a 1 $\rightarrow$ 4- $\beta$ -glycoside bond, while the two monosaccharides in maltose are joined by a 1 $\rightarrow$ 4- $\alpha$ -glycoside bond.
C)Lactose contains both an acetal and a hemiacetal, while maltose contains two acetals.
D)Lactose can be hydrolyzed in the body, but maltose cannot.

Question 26

What monosaccharide is found in cellulose, starch, and glycogen?

A)glucose
B)galactose
C)sucrose
D)fructose

Question 27

Dihydroxyacetone, shown below, is the simplest ketose. Does the structure shown represent D-dihydroxyacetone or L-dihydroxyacetone?

A)D-dihydroxyacetone
B)L-dihydroxyacetone
C)Neither D nor L; dihydroxyacetone is not chiral
D)It is impossible to tell from the Fischer projection alone.

Question 28

What is responsible for the different blood types in humans?

A)three or four proteins attached to a membrane monosaccharide on the surface of red blood cells
B)three or four monosaccharides attached to a membrane protein on the surface of red blood cells
C)three or four amino acids attached to a membrane monosaccharide on the surface of red blood cells
D)three or four lipids attached to a membrane polysaccharide on the surface of red blood cells

Question 29

What type of polysaccharide is depicted in the "cartoon" shown below?

A)cellulose
B)amylose
C)amylopectin
D)chitin

Question 30

Which is not a reducing sugar?

A)glucose
B)fructose
C)sucrose
D)galactose
E)an aldopentose

Question 31

Chitin is identical in structure to cellulose, except that

A)the linkages are $\alpha$ -glycoside linkages.
B)each OH group at C4 is replaced by NHCOCH₃.
C)each OH group at C2 is replaced by NH₃.
D)each OH group at C2 is replaced by NHCOCH₃.

Question 32

Which naturally-occurring monosaccharide forms the Haworth structure shown?

A)
B)
C)
D)

Question 33

Which carbohydrate derivative forms a gel-like matrix in joints and the vitreous humor of the eye?

A)heparin
B)chondroitin
C)hyaluronate
D)chitin

Question 34

Salicin is a naturally occurring, carbohydrate-containing pain reliever. Which statement concerning the functional groups present in salicin is incorrect?

A)Salicin contains an acetal.
B)Salicin contains an alcohol.
C)Salicin contains a hemiacetal.
D)Salicin contains a phenol.

Question 35

What is the polysaccharide form in which glucose is stored in animals?

A)cellulose
B)amylose
C)amylopectin
D)glycogen

Question 36

What is the structure of cellulose?

A)unbranched skeleton of glucose molecules joined by 1 $\rightarrow$ 4- $\alpha$ -glycoside linkages
B)branched skeleton of glucose molecules joined by 1 $\rightarrow$ 4- $\alpha$ -glycoside linkages
C)unbranched skeleton of glucose molecules joined by 1 $\rightarrow$ 4- $\beta$ -glycoside linkages
D)branched skeleton of glucose molecules joined by 1 $\rightarrow$ 4- $\beta$ -glycoside linkages

Question 37

Why are humans not able to digest cellulose?

A)Humans cannot digest glucose.
B)Humans do not possess the enzyme necessary to hydrolyze the 1 $\rightarrow$ 4- $\beta$ -glycoside linkages found in cellulose.
C)Humans do not possess the enzyme necessary to unwind the helical shape of the cellulose molecule.
D)Humans do not possess the enzyme necessary to hydrolyze the 1 $\rightarrow$ 4- $\alpha$ -glycoside linkages found in cellulose.

Question 38

The simplest aldose is commonly called glyceraldehyde, although its IUPAC name is 2, 3-dihydroxypropanal. What is the structure of this compound?

A)
B)
C)
D)

Question 39

Which structure is a three-carbon alditol?

A)
B)
C)
D)

Question 40

Which is not a glycosaminoglycan?

A)hyaluronate
B)chitin
C)heparin
D)chondroitin

Question 41

The monosaccharide shown below is an $\alpha$ anomer.

Question 42

Gentobiose, a rare disaccharide found in saffron, produces two identical monosaccharides when it undergoes hydrolysis. What is the identity of the hydrolysis product?

A)
B)
C)
D)

Question 43

The Fischer projections of two monosaccharides are shown below. Which term best describes the relationship between the two?

A)enantiomers
B)anomers
C)constitutional isomers
D)diastereomers

Question 44

Which statement concerning carbohydrates is incorrect?

A)Carbohydrates serve important energy and structural roles for both plants and animals.
B)Monosaccharides are the simplest carbohydrates and are known as simple sugars.
C)Humans store excess glucose for short term energy requirements in the polysaccharide cellulose.
D)Carbohydrates that can be oxidized by Benedict's reagent are called reducing sugars.

Question 45

The monosaccharide shown below is an $\alpha$ anomer.

Question 46

The $\beta$ anomer of a cyclic monosaccharide has the -OH group drawn down, below the ring.

Question 47

At equilibrium, a solution of glucose in water is an equal mixture of the $\alpha$ anomer, the $\beta$ anomer, and the acyclic aldehyde.

Question 48

A hemiacetal is a compound that contains a hydroxyl group (-OH)and an alkoxy group (-OR)on adjacent carbon atoms.

Question 49

Carbohydrates that are oxidized with Benedict's reagent are called reducing sugars, because they reduce the Cu²⁺ in Benedict's reagent to Cu⁺ during the reaction.

Question 50

An $\alpha$ glycoside has the glycosidic linkage oriented down, below the plane of the ring that contains the acetal joining the monosaccharides.

Question 51

An alditol contains an -OH group on every carbon atom.

Question 52

The carbonyl group of an aldose is reduced to a secondary alcohol using hydrogen (H₂)in the presence of palladium (Pd)metal.

Question 53

When a monosaccharide forms a cyclic hemiacetal, the carbon atom that is part of the hemiacetal is a new chirality center, called the anomeric carbon.

Question 54

All disaccharides contain at least one acetal that joins the rings together.

Question 55

Certain monosaccharides-notably aldopentoses and ketohexoses-form five-membered rings, not six-membered rings, in solution.

Question 56

Melibiose is a carbohydrate found in some plant juices. Which statement concerning melibiose is incorrect?

A)It is a disaccharide.
B)It is composed of two different monosaccharides.
C)It contains both an acetal and a hemiacetal.
D)It contains a 1 $\rightarrow$ 5- $\alpha$ -glycosidic linkage.

Question 57

All aldoses and ketoses are reducing sugars.

Question 58

Modern glucose meters are electronic devices that measure the amount of oxidizing agent that reacts with the glucose in a known amount of blood.

Question 59

Which of the following is not a term that would properly describe glucose as it is shown below?

A)monosaccharide
B)aldohexose
C)reducing sugar
D) $\beta$ -D-glucose

Question 60

Test strips that contain the enzyme lactase are used to measure glucose concentration in urine.

Question 61

The conversion of D-ribose to L-ribose is an example of mutarotation.

Question 62

$\alpha$ -D-galactose and $\beta$ -D-galactose are enantiomers.

Question 63

In aldohexoses, it is the -OH group on C5 that reacts with the aldehyde carbonyl to form two cyclic hemiacetals called anomers.

Question 64

Monosaccharides are polar compounds with low melting points.

Question 65

Carbohydrates are chiral biomolecules. The term chiral indicates that carbohydrates can be both synthesized and digested by the human body.

Question 66

Carbohydrates serve important energy and structural roles for both plants and animals.

Question 67

In the disaccharide structure shown, the anomeric carbons are properly labeled.

Question 68

Monosaccharides with a carbonyl group at C2 are called ketoses.

Question 69

The two compounds N-acetyl-D-glucosamine and N-acetyl-D-galactosamine are a set of constitutional isomers.

Question 70

Cellulose is a highly branched polymer composed of repeating glucose units joined in a 1 $\rightarrow$ 4- $\beta$ -glycosidic linkage.

Question 71

In addition to the three monosaccharides that occur in all blood types, type A blood contains the monosaccharide N-acetyl-D-galactosamine, and type B blood contains an additional D-galactose unit.

Question 72

Carbohydrates are structurally defined as polyhydroxyaldehydes and polyhydroxyketones, or compounds that can be hydrolyzed to them.

Question 73

The disaccharide shown below has an $\alpha$ -glycosidic linkage.

Question 74

Disaccharides contain two carbonyl groups.

Question 75

Glucose and other naturally occurring sugars are D sugars.

Question 76

Maltose is a reducing sugar.

Question 77

Individuals with type AB blood are called universal recipients because their blood contains no antibodies to blood types A, B, or O. Individuals with type AB blood can receive blood of any type.

Question 78

The structure shown has four (4)chirality centers and is a D monosaccharide.

Question 79

Hydrolysis of the disaccharide below yields the indicated products.

Question 80

When the monosaccharide below is oxidized by Benedict's reagent, the indicated product results.