Deck 16: Carbohydrates

Question 1

Which carbohydrate is present in RNA?

A)ribulose
B)glucose
C)mannose
D)ribose
E)fructose

Answer 1

ribose

Question 2

Which enantiomer of glyceraldehyde is represented in the following structure?

A)L-glyceraldehyde
B)α-glyceraldehyde
C)β-glyceraldehyde
D)D-glyceraldehyde
E)It is impossible to determine from the structure alone.

Answer 2

L-glyceraldehyde

Question 3

A ketose can be converted to an aldose through an enediol intermediate.What is the structure of the enediol intermediate when D-fructose is converted to D-glucose?

A)
B)
C)
D)
E)

Answer 3

Question 4

How do the structures of amylose and cellulose differ?

A)Amylose is a linear polysaccharide and cellulose is a branched polysaccharide.
B)Amylose is a homopolysaccharide and cellulose is a heteropolysaccharide.
C)Amylose is a polysaccharide of glucose units, and cellulose is a polysaccharide of galactose units.
D)Amylose is a polysaccharide made up of D-glucose units, and cellulose is a polysaccharide made up of L-glucose units.
E)Amylose contains α(1→4) glycosidic bonds joining D-glucose units, and cellulose contains β(1→4) glycosidic bonds joining D-glucose units.

Question 5

Monosaccharides are structurally defined as which of the following?

A)polyhydroxyaldehydes or polyhydroxyketones
B)hemiacetals and acetals
C)polyamides or polyesters
D)enols and enolates
E)carboxylic acids

Question 6

How does the structure of α-D-glucose differ from that of β-D-glucose?

A)α-D-Glucose is an aldose and β-D-glucose is a ketose.
B)In α-D-glucose the −OH group on the last chiral carbon is on the left, and in β-D-glucose the −OH group on the last chiral carbon is on the right.
C)In α-D-glucose the −OH group on the hemiacetal carbon is below the ring, and in β-D-glucose the −OH group on the hemiacetal carbon is above the ring.
D)In α-D-glucose the last −CH₂OH group is on the right, and in β-D-glucose the −CH₂OH group is on the left.
E)There is no structural difference between the two.

Question 7

What disaccharide is composed of two glucose units joined together?

A)lactose
B)maltose
C)sucrose
D)cellulose
E)galactose

Question 8

What is a reducing sugar?

A)a carbohydrate that can be oxidized by Benedict?s reagent
B)a sugar that contains an acetal
C)a carbohydrate that can be reduced by Benedict?s reagent
D)a sugar that can be digested by the body
E)a carbohydrate that is part of a polysaccharide

Question 9

What test can be used to distinguish between a reducing sugar and a nonreducing sugar?

A)iodine test
B)Tollens' test
C)chromic acid test
D)Benedict's test
E)hydrolysis test

Question 10

What two monosaccharides join to form the disaccharide lactose?

A)glucose and galactose
B)galactose and fructose
C)ribose and galactose
D)glucose and fructose
E)glucose and glucose

Question 11

What term is used to describe an excess of glucose in a urine sample?

A)glucosamine
B)glucosemia
C)glucosuria
D)hypoglucose
E)glucagon

Question 12

What is the most abundant carbohydrate on Earth?

A)sucrose
B)cellulose
C)glycogen
D)fructose
E)amylose

Question 13

Starch is composed of which two polysaccharides?

A)chitin and chondroitin
B)glycogen and cellulose
C)amylose and amylopectin
D)glucosamine and glycogen
E)cellulose and galactosamine

Question 14

Propranol is a chiral compound that exists as a pair of enantiomers.One enantiomer is used to treat irregular heartbeats, and the other is used as a contraceptive.Which labeled carbon atom(s) is/are chiral?

A)C-1
B)C-2
C)C-3
D)C-4
E)C-1 and C-3

Question 15

Carbohydrates are chiral or "handed" biomolecules.What does the term chiral describe?

A)a molecule that has a mirror image
B)a molecule that can be superimposed on its mirror image
C)a molecule that exists in two nonsuperimposable mirror image forms
D)a molecule that can be digested by the body
E)a molecule that may be synthesized by the body

Question 16

Which of the following statements concerning stereochemistry is INCORRECT?

A)Stereoisomers are molecules with the same molecular formula, same bonding pattern, but different spatial arrangement of atoms.
B)A chiral carbon is a carbon atom that has four different groups bonded to it.
C)A molecule that contains a chiral carbon is a chiral molecule, and exists as a pair of enantiomers.
D)Enantiomers are superimposable mirror image stereoisomers.
E)A racemic mixture of enantiomers is optically inactive.

Question 17

The simplest aldose is named 2,3-dihydroxypropanal, although it is more commonly referred to as glyceraldehyde.What is the structure of glyceraldehyde?

A)
B)
C)
D)
E)

Question 18

What are the major sites of glycogen storage in the human body?

A)fat and pancreas
B)liver and muscle
C)stomach and intestines
D)kidneys and stomach
E)heart and brain

Question 19

Amylose and amylopectin are both components of starch.How do their structures differ?

A)Amylose is a monosaccharide and amylopectin is a polysaccharide.
B)Amylose is a polysaccharide and amylopectin is a disaccharide.
C)Amylose is an aldose and amylopectin is a ketose.
D)Amylose is a linear polysaccharide and amylopectin is a branched polysaccharide.
E)Amylose is a hexose and amylopectin is a pentose.

Question 20

What two monosaccharides combine to form sucrose?

A)glucose and galactose
B)galactose and fructose
C)ribose and galactose
D)glucose and fructose
E)ribose and fructose

Question 21

What is the simplest type of carbohydrate?

A)sugars
B)monosaccharides
C)cellulose
D)starch
E)None of the choices are correct.

Question 22

The Fischer projection for the monosaccharide ribulose is shown below.How may this monosaccharide be appropriately classified?

A)ketotetrose
B)ketopentose
C)aldotriose
D)aldopentose
E)ketotriose

Question 23

What two functional groups are present in all monosaccharides?

A)hydroxyl and carboxyl
B)alkene and phosphate
C)acid and carbonyl
D)amino and hydroxyl
E)hydroxyl and carbonyl

Question 24

What complex carbohydrate provides a source of dietary fiber?

A)starch
B)cellulose
C)lactose
D)sucrose
E)glucose

Question 25

The monosaccharide derivative shown below bonds to hydrophobic molecules in the liver.What effect does this have on the molecule to which it binds?

A)It increases the hydrophobicity of the molecule, making it more soluble in fatty tissues.
B)It increases the polarity of the molecule, making it more soluble in bodily fluids, and more readily removed.
C)It eliminates the ability of the molecule to act as a nutritional source of energy.
D)It decreases the polarity of the hydrophobic molecule, allowing it to be retained in the body longer.
E)It increases the nutritional value of the molecule by allowing it to be retained by the body longer.

Question 26

What term describes a carbon atom that has four different groups bonded to it?

A)chiral
B)unbalanced
C)trigonal pyramidal
D)meso
E)unsaturated

Question 27

What term properly describes the relationship between the two compounds shown?

A)betamers
B)constitutional isomers
C)enantiomers
D)anomers
E)unrelated

Question 28

What type of compound is produced in the reaction between an alcohol and an aldehyde?

A)diol
B)carboxylic acid
C)acetal
D)hemiacetal
E)ester

Question 29

What is the molecular formula of glucose?

A)C₆H₁₂O₅
B)C₆H₁₂O₆
C)C₆H₁₀O₅
D)C₅H₁₀O₅
E)C₉H₁₈O₉

Question 30

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

A)dipole/dipole forces
B)hydrogen bonding
C)hemiacetal bonds
D)glycosidic linkages
E)peptide bonds

Question 31

The structure of ribose, found in RNA, is shown below.How does the structure of deoxyribose, found in DNA, compare to it?

A)Deoxyribose has one less oxygen.
B)Deoxyribose has one more oxygen.
C)Deoxyribose has one less oxygen and one less hydrogen.
D)Deoxyribose has one less hydrogen.
E)Deoxyribose has one less oxygen and two less hydrogens.

Question 32

Which enantiomer of glyceraldehyde is represented in the following structure?

A)trans
B)α
C)β
D)D
E)L

Question 33

To what class of carbonyl-containing compounds does glucose belong?

A)aldehyde
B)ketone
C)alcohol
D)amide
E)Both aldehyde and ketone are correct.

Question 34

What is the name of the simplest ketose?

A)acetone
B)fructose
C)ethanone
D)1,3-dihydroxyacetone
E)ethose

Question 35

What is the stereochemical relationship between your right and left hands?

A)cis- and trans- isomers
B)structural isomers
C)conformers
D)enantiomers
E)diastereomers

Question 36

What term describes carbohydrates consisting of two to ten monosaccharide units bonded together?

A)disaccharide
B)polysaccharide
C)oligosaccharide
D)glycogen
E)starch

Question 37

Monosaccharides exist predominantly as cyclic hemiacetals.Cyclic hemiacetals have both an α and a β form.Which of the following monosaccharides are shown in the β form?

A)III only
B)IV only
C)I and III
D)II and IV
E)All are shown in the β form.

Question 38

Which monosaccharide found in the blood has its concentration regulated by the hormones insulin and glucagon?

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

Question 39

Which property of D-glyceraldehyde and L-glyceraldehyde differs?

A)melting point
B)solubility
C)direction of rotation of plane-polarized light
D)density
E)None of the choices are correct.

Question 40

The Fischer projections of two monosaccharides are shown below.What is the relationship between the two monosaccharides?

A)enantiomers
B)diastereomers
C)structural isomers
D)meso isomers
E)cis-trans isomers

Question 41

What polysaccharide found in animals has a structure very similar to amylopectin?

A)glucose
B)glycogen
C)starch
D)amylose
E)cellulose

Question 42

Which of the following is a nonreducing disaccharide?

A)mannose
B)maltose
C)sucrose
D)lactose
E)ribose

Question 43

Which of the following is NOT a carbohydrate?

A)sucrose
B)simple sugar
C)fatty acid
D)cellulose
E)starch

Question 44

Melibiose is a carbohydrate found in some plant juices.Which of the following statements concerning melibiose is INCORRECT?

A)It is a disaccharide.
B)It is composed of two different monosaccharide units.
C)It contains both an acetal and a hemiacetal.
D)It contains an α(1→5) glycosidic linkage.
E)It is a reducing sugar.

Question 45

What type of product forms in the intramolecular reaction between the aldehyde portion of the glucose molecule below and its C-5 hydroxyl group?

A)disaccharide
B)ester
C)carboxylic acid
D)stereoisomer
E)hemiacetal

Question 46

Which statement concerning a chiral carbon is always TRUE?

A)A chiral carbon is bonded to four different atoms or groups of atoms.
B)A chiral carbon is bonded to a hydroxyl group and carbonyl group.
C)A chiral carbon has two double bonds connected to it.
D)A chiral carbon causes plane-polarized light to rotate in a clockwise fashion.
E)A chiral carbon is present in all aldehydes.

Question 47

What heteropolysaccharide is a component of cartilage and may relieve symptoms of osteoarthritis?

A)chondroitin sulfate
B)hyaluronic acid
C)heparin
D)glycogen
E)α-D-glucuronate

Question 48

The Fischer projection for the naturally occurring form of fucose, one of the carbohydrates used as a cell marker in the determination of blood types, is shown below.Is this D-fucose or L-fucose?

A)D-fucose
B)L-fucose
C)It is neither D- nor L-; fucose is not chiral.
D)It is impossible to determine from the Fischer projection alone.

Question 49

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

A)
B)
C)
D)
^E. None of these are correct.

Question 50

Which statement is FALSE?

A)Molecules that contain a chiral carbon will rotate plane-polarized light.
B)If one molecule rotates plane-polarized light clockwise 10°, its enantiomer will rotate plane-polarized light counterclockwise by 10°.
C)The D- and L- designation of sugars is determined by the chiral atom farthest from the most oxidized carbon.
D)All sugars designated with a D- prefix will rotate plane-polarized light in a clockwise direction.
E)Dextrorotatory sugars rotate plane-polarized light clockwise and are designated by a plus sign (+).

Question 51

A laboratory sample contains enantiomers present in equal concentrations.Which of the following statements concerning this sample is FALSE?

A)The sample contains a racemic mixture.
B)The sample will be optically inactive.
C)The sample contains two different compounds related as non-superimposable mirror image isomers.
D)The sample contains a meso compound.

Question 52

What is the principal carbohydrate found in milk?

A)glucose
B)maltose
C)mannose
D)lactose
E)sucrose

Question 53

Which of the following is a highly branched polymer of glucose?

A)dextran
B)cellulose
C)amylose
D)amylopectin
E)peptidoglycan

Question 54

Which monosaccharide combines with glucose to form the disaccharide lactose?

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

Question 55

Which of the following correctly matches the term with its definition?

A)ketose - monosaccharide with a ketone functional group
B)aldose - monosaccharide with a carbonyl group on the end carbon
C)tetrose - has the formula (CH₂O)_n where n = 4
D)pentose - a five carbon sugar
E)All of the choices are correct.

Question 56

What type of glycosidic linkage between glucose units is present in cellulose?

A)α(1→4)
B)β(1→4)
C)α(1→6)
D)β(1→6)
E)α(1→4) and α(1→6)

Question 57

Which form of D-glucose has the -OH group on carbon-1 below the ring in the Haworth projection?

A)meso
B)L
C)α
D)β
E)γ

Question 58

Which of the following carbohydrates cannot be digested by humans?

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

Question 59

Which of the following carbohydrates is also known as dextrose, and is the sugar referred to when blood sugar is measured?

A)glycogen
B)sucrose
C)glucose
D)starch
E)lactose

Question 60

What is the position of the -OH group on carbon-1 in the Haworth projection of β-D-glucose?

A)above the ring
B)below the ring
C)in the plane of the ring
D)to the left of carbon-1
E)to the right of carbon-1

Question 61

For D-glyceraldehyde shown below, which carbon, if any, is chiral?

A)C-1
B)C-2 and C-3
C)C-2
D)None of the carbon atoms are chiral.
E)C-3

Question 62

Which of the following is the major storage molecule of glucose in animals?

A)cellulose
B)sucrose
C)blood sugar
D)amylose
E)glycogen

Question 63

A meso compound is a chiral compound because it contains two chiral carbons and an internal plane of symmetry.

Question 64

Enantiomers are related as non-superimposable mirror images.

Question 65

Aldaric acids are a type of monosaccharide derivative, formed when both the aldehyde group and the terminal -CH₂OH group of a monosaccharide are oxidized to carboxylic acids.D-Glucaric acid is the aldaric acid derivative of D-glucose.What is the structure of D-glucaric acid?

A)I
B)II
C)III
D)IV
E)V

Question 66

Cellulose molecules are all unbranched, while starch contains only branched molecules.

Question 67

If D-glucose is levorotatory, then L-glucose must be levorotatory as well.

Question 68

All monosaccharides give a positive result with Benedict's reagent.

Question 69

The glycosidic linkages found in most disaccharides and polysaccharides are acetal bonds.

Question 70

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

A)monosaccharide
B)aldose
C)hemiacetal
D)D-sugar
E)reducing sugar

Question 71

A termite's digestive organs produce a cellulase that allows it to break down wood fibers.

Question 72

Which of the following is NOT a common name for D-glucose?

A)table sugar
B)dextrose
C)grape sugar
D)blood sugar
E)All of the choices are correct.

Question 73

If left untreated, galactosemia leads to mental retardation.

Question 74

The principal carbohydrate in milk is galactose.