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Exam 1 Flashcards

1
Q

Identify the functions of carbohydrates in the
human body.

a. They provide energy during their oxidation and a short-term energy reserve.
b. They form part of the framework for nucleic acids and supply

carbon atoms for synthesis of other biomolecules.
c. When linked to proteins, they are involved in the cell–cell and cell–molecule recognition process, and they function asstructural components of cell membranes when linked to lipids.

d. All the above.

A

d. All of the above

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2
Q

Biochemistry, the study of the chemical
substances of living organisms, includes the study
of:

a. carbohydrates, lipids, proteins, and salts.
b. carbohydrates, lipids, proteins, and organic salts.
c. carbohydrates, lipids, proteins, and nucleic acids.
d. carbohydrates, lipids, and proteins.

A

C. carbohydrates, lipids, proteins, and nucleic acids.

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3
Q

Process in which plants produce carbohydrates

using carbon dioxide, water, and solar energy

A

Photosynthesis

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4
Q

It is estimated that more than __ of all organic
carbon atoms are found in the carbohydrate
materials of plants.

A. 50%
B. 25%
C. 100%
D.75%

A

A. 50%

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5
Q

What are some uses for for carbohydrates outside of food?

A

Carbohydrates in the form of cotton and linen are
used as clothing

Carbohydrates in the form of wood are used for
shelter and heating and in making paper

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6
Q

Most of the matter in plants, except water, is?

A

Carbohydrate Material.

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7
Q

what accounts for 75% of dry plant

material and are produced by photosynthesis?

A

Carbohydrates

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8
Q

What are 6 Functions of Carbohydrates in the Human Body?

A

Carbohydrate oxidation provides energy.

• Carbohydrate storage, in the form of glycogen,
provides a short-term energy reserve

• Carbohydrates supply carbon atoms for the
synthesis of other biochemical substances
(proteins, lipids, and nucleic acids)

• Carbohydrates form part of the structural
framework of DNA and RNA molecules

Carbohydrates linked to lipids are structural
components of cell membranes

• Carbohydrates linked to proteins function in a
variety of cell–cell and cell–molecule recognition
processes

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9
Q

Empirical formula of simple carbohydrates -

A

CnH2nOn (n is the number of atoms)

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10
Q

Polyhydroxy aldehyde, ketone,
or a compound that produces such substances
upon hydrolysis

A

Carbohydrate

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11
Q

What contains single polyhydroxy aldehyde or ketone

unit

A

Monosaccharides

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12
Q

What cannot be broken down into simpler substances

by hydrolysis reactions

A

Monosaccharides

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13
Q

What contains 2 monosaccharide units covalently

bonded to each other

A

Disaccharides

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14
Q

Contains 3–7 C atoms

A

Monosaccharides

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15
Q

Upon hydrolysis, they produce 2

monosaccharide units

A

Disaccharides

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16
Q

5 and 6 carbon species are more common

A

Monosaccharides

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17
Q

What are Pure Monosaccharides

A

Water soluble white,

crystalline solids

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18
Q

Common Disaccharides

A 
Table sugar (sucrose)
and milk sugar (lactose)
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19
Q

Upon hydrolysis, they produce 2

monosaccharide units

A

Disaccharides

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20
Q

Contain three to ten monosaccharide units

covalently bonded to each other

A

Oligosaccharides

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21
Q

Free _____ are seldom encountered

in biochemical systems

A

Oligosaccharides

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22
Q

Usually found associated with proteins and lipids

in complex molecules

A

Oligosaccharides

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23
Q

Contain many monosaccharide units covalently
bonded
• Number of monosaccharide units varies from a
few 100 units to 50,000 units

A

Polysaccharides

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24
Q

Name 3 Examples of Polysaccharides

A

Cellulose - Paper, cotton, wood
– Starch - Bread, pasta, potatoes, rice, corn, beans,
and peas

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25
Q

Carbohydrates are classified as:

a. monosaccharides, disaccharides, oligosaccharides, and polysaccharides.
b. polyhydroxy aldehydes or ketones.
c. monosaccharides and disaccharides.
d. monosaccharides, oligosaccharides, polysaccharides, and polyhydroxy aldehydes or ketones.

A

a. monosaccharides, disaccharides, oligosaccharides, and polysaccharides

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26
Q

C atom attached to 4 different

groups

A

Chiral center

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27
Q

Bromochloroiodomethane is a ___ organic molecule

A

Chiral

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28
Q 
A carbohydrate molecule whose mirror image is
not superimposable is said to be a \_\_\_\_\_
molecule.
a. achiral
b. chiral
c. nonidentical
d. nonsuperimposable
A

b. chiral

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29
Q

Two Types of Stereoisomers

A

Enantiomers: Stereoisomers whose molecules are
non-superimposable mirror images of each other
• Molecules with chiral center

– Diastereomers: Stereoisomers whose molecules are
not mirror images of each other
• Example: Cis-trans isomers

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30
Q

What feature does a carbohydrate possess that
generates stereoisomerism?
a. Presence of a chiral center
b. Presence of structural rigidity
c. Presence of three or more carbon atoms
d. Presence of an achiral center

A

a. Presence of a chiral center

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31
Q

Two-dimensional structural notation for showing
the spatial arrangement of groups about chiral
centers in molecules
• According to this formula, a chiral center is
represented as the intersection of vertical and
horizontal lines
• Functional groups of high priority will be written
at the top

A

Fischer Project Formula (see slides 31-33)

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32
Q

• The four groups attached to the atom at the
chiral center assume a tetrahedral geometry
governed by the following conventions:

A

Tetrahedral Arrangements (See slide 30)

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33
Q

What formula is used to show the two-dimensional
structure of groups around chiral centers in a
molecule?

A

Fischer projection

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34
Q
  • Vibrational Characteristics of Ordinary

Light and Plane-Polarized Light

A

See Slide 38

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35
Q

Name the properties of Ordinary light waves and Plane polarized light waves

A

Ordinary: Vibrate in all directions

Plane Polarized Light Waves: One direction

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36
Q

Dextrorotatory compound: Chiral compound
that rotates light towards ___
• Levorotatory compound: Chiral compound that
rotates light towards ___

A

Dextrorotatory: Right (Clockwise)
Levorotatory: Left (Counterclockwise)

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37
Q

Interactions Between Chiral Compounds

A

Check Slides 40 and 41

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38
Q

What is meant when it is said that carbohydrates
are optically active compounds?
a. A solution of carbohydrate when placed in a light beam
reflects the light back to the observer.
b. A solution of carbohydrate will rotate the plane of
polarized light.
c. A solution of carbohydrate will not rotate the plane of
polarized light.
d. Being optically active, they do not possess handedness.

A

b.A solution of carbohydrate will rotate the plane of

polarized light.

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39
Q

Triose

A

3 carbon atoms

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40
Q

Tetrose

A

4 carbon atoms

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41
Q

Pentoses

A

5 carbon atoms

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42
Q

Hexoses

A

6 carbon atoms

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43
Q

Aldoses:

A

Monosaccharides with one aldehyde

group

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44
Q

Ketoses:

A

Monosaccharides with one ketone group

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45
Q

Aldohexose

A

Monosaccharide with aldehyde group

and 6 C atom

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46
Q

Ketopentose

A

Monosaccharide with ketone group and

5 C atoms

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47
Q

What structural feature distinguishes an aldose
and a ketose?
a. An aldose possesses an aldehyde group, and a ketose
possesses a ketone group.
b. An aldose contains 5 carbon atoms, and a ketose
contains 6 carbon atoms.
c. An aldose possesses only –OH groups, and a ketose
possesses a carbonyl group.
d. An aldose possesses a ketone group, and a ketose
possesses an aldehyde group.

A

a. An aldose possesses an aldehyde group, and a ketose

possesses a ketone group.

48
Q

4 Groups of Monosaccharides

A

Ketoses, Aldohexose, Ketopentose, Aldoses

49
Q

Most abundant in nature

Most important source of human nutrition

A

D-Glucose

50
Q

Other names for Glucose

A

– Dextrose

– Blood sugar

51
Q

Glucose is a Six-membered cyclic form

A

see slide 50

52
Q 
Milk sugar
• Synthesized in human beings
• Also called brain sugar
– Part of brain and nerve tissue
• Used to differentiate between blood
types
A

D-Galactose

53
Q

D-Galactose is a Six-membered cyclic form

A

See Slide 51

54
Q 
Ketohexose
• Sweetest tasting of all sugars
– Found in many fruits and in honey
• Good dietary sugar due to
higher sweetness
A

D-Fructose

55
Q

D-Fructose is a Five-membered cyclic form

A

See Slide 52

56
Q 
Part of a variety of complex molecules which
include:
– RNA
– ATP
– DNA
A

D-Ribose

57
Q

D-Ribose is a Five-membered cyclic form

A

see slide 53

58
Q

Which monosaccharide is the most important from

a human nutritional standpoint?

A

Glucose

59
Q

Cyclic Hemiacetal Forms of D-Glucose

A

• Dominant forms of monosaccharides with 5 or

more C atoms

60
Q

Cyclic structures are formed by

A

the reaction of
carbonyl group (C=O) with hydroxyl (–OH) group
on carbon 5

61
Q

Cyclic monosaccharides that differ only in the
position of the substituents on the anomeric
carbon atom

A

Anomers (see slide 57, 58)

62
Q

Cyclic monosaccharide containing a

five-atom ring

A

Furanose

63
Q

Cyclic monosaccharide containing a

six-atom ring

A

Pyranose

64
Q

Monosaccharides in nature have cyclic forms
because they can form:
a. internal acetals that are stable.
b. internal hemiacetals that are stable.
c. internal acetals that are rapidly converted to stable
hemiacetals.
d. internal hemiacetals that are rapidly converted to stable acetals.

A

b. internal hemiacetals that are stable.

65
Q

Two-dimensional
structural notation that specifies the threedimensional structure of a cyclic form of a
monosaccharide

A

Haworth projection formula

66
Q

α and β Configuration

A

Slide 64

67
Q

–OH Group Position

A

Slide 65

68
Q

Haworth projection formula for a monosaccharide
is a formula showing:
a. a line structure of a stable internal acetal.
b. a two-dimensional notation that specifies the three dimensional structure of a cyclic monosaccharide.
c. a line structure of a stable internal hemiacetal.
d. a two-dimensional notation that specifies the three dimensional structure of a stable cyclic acetal.

A

b. a two-dimensional notation that specifies the three dimensional structure of a cyclic monosaccharide.

69
Q

Which of the monosaccharides glucose, fructose,
galactose, and ribose has each of the following
structural characteristics? (There may be more than
one correct answer for a given characteristic)

a. It is a pentose.
b. It is a ketose.
c. Its cyclic form has a 6-membered ring.
d. Its cyclic form has two carbon atoms outside the ring.

A

a. It is a pentose: Ribose
b. It is a ketose: Fructose
c. Its cyclic form has a 6-membered ring: Glucose,
and galactose
d. Its cyclic form has two carbon atoms outside the ring:
Fructose

70
Q

Five important reactions of monosaccharides:

A 
Oxidation to acidic sugars
– Reduction to sugar alcohols
– Glycoside formation
– Phosphate ester formation
– Amino sugar formation
71
Q
  • Formed when weak oxidizing agents
    such as Tollens and Benedict’s solutions oxidize the
    aldehyde end
A

Aldonic acid

72
Q

Carbohydrate that gives a positive

test with Tollens and Benedict’s solutions

A

Reducing Sugar

73
Q

Sorbitol

A

Used as a moisturizing agent in foods and
cosmetics and as a sweetening agent in chewing
gum

74
Q

Acetal formed from a cyclic
monosaccharide by replacement of the
hemiacetal carbon –OH group with an –OR
group

A

Glycoside

75
Q

Glycoside produced from glucose

A

Glucoside

76
Q

Glycoside produced from galactose

A

Galactoside

77
Q

Hydroxyl groups of a monosaccharide can react
with inorganic oxyacids to form inorganic esters
• Phosphate esters of various monosaccharides
are stable in aqueous solution and play
important roles in the metabolism of
carbohydrates

A

Phosphate Ester Formation

78
Q
  • Formed when one of the hydroxyl
    groups of a monosaccharide is replaced with an
    amino group
A

Amino sugar

79
Q 
Which of the following sugars can be oxidized by
Tollens and Benedict’s reagents in basic
conditions?
a. D-glucose, an aldohexose
b. D-fructose, a ketohexose
c. D-mannose, an aldohexose
d. All the above
A

d. All the above

80
Q

Maltose (Malt Sugar)

A

See Slide 80

81
Q

Cellobiose

A

See Slide 81

82
Q

Lactose

A

See Slide 82

83
Q

a condition in which
people lack the enzyme lactase needed to
hydrolyze lactose to galactose and glucose

A

Lactose intolerance

see slide 84 for more information on what happens

84
Q

The most abundant of all disaccharides and
found in plants
• Produced commercially from the juice of sugar
cane and sugar beets

A

Sucrose (Table Sugar)

85
Q

What is the linkage that is formed when two
monosaccharides react to form a disaccharide
called?
a. Alcohol group linkage
b. Glycosidic linkage
c. Hemiacetal linkage
d. Acetal linkage

A

b. Glycosidic linkage

86
Q 
Which disaccharide is a nonreducing sugar?
a. Maltose
b. Lactose
c. Cellobiose
d .Sucrose
A

d. Sucrose

87
Q

Which of these disaccharides, i.e., maltose, cellobiose,
lactose, and sucrose, have the following structural or
reaction characteristics? (There may be more than one
correct answer for a given characteristic)

a. Two different monosaccharide units are present.
b. Hydrolysis produces only monosaccharides.
c. Its glycosidic linkage is a “head-to-head” linkage.
d. It is not a reducing sugar

A

a. Two different monosaccharide units are present.
Lactose, sucrose

b. Hydrolysis produces only monosaccharides.
Maltose, cellobiose, lactose, sucrose

c. Its glycosidic linkage is a “head-to-head” linkage.
Sucrose

d.It is not a reducing sugar.
Sucrose

88
Q

Carbohydrates that contain 3–10
monosaccharide units bonded to each other via
glycosidic linkages

A

Oligosaccharides

89
Q

Blood Types and Oligosaccharides

A

See Slide 93 and 94

90
Q 
Which of the following is a toxin produced by
potato plants?
a. Raffinose
b. Stachyose
c. Solanine
d. None of the above
A

c. Solanine

91
Q

Polymers of many
monosaccharide units bonded with glycosidic
linkages

A

Polysaccharides

92
Q

Two types of Polysaccharides

A

– Homopolysaccharide

– Heteropolysaccharide

93
Q

Not sweet and do not show
positive tests with Tollen’s and Benedict’s
solutions, whereas monosaccharides are sweet
and show positive tests
• Limited water solubility

A

• Polysaccharides

94
Q

A _____ is a polysaccharide in which only one
type of monosaccharide monomer is present.

a. heteropolysaccharide
b. homopolysaccharide
c. heteromonosaccharide
d. homomonosaccharide

A

b. homopolysaccharide

95
Q

Polysaccharide that is
a storage form for monosaccharides and used
as an energy source in cells

A

Storage polysaccharide

96
Q

Glucose is the monomeric unit

– Storage polysaccharide in plants

A

Starch

97
Q

Types of Polysaccharides Isolated From Starch

A

Amylose, • Amylopectin

98
Q 
Glucose storage polysaccharide in humans and
animals
• Contains only glucose units
• Branched chain polymer with α(1->4) glycosidic
bonds in straight chains and α(1->6) in
branches
• Three times more highly branched than
amylopectin in starch
• Contains up to 1,000,000 glucose units
A

Glycogen

99
Q

Excess glucose in blood is stored in the form of:

A

Glycogen

100
Q

In starch, two different glucose-containing
polysaccharides can be isolated. They are _____
and _____

a. glycogen; amylose
b. amylose; amylopectin
c. amylose; cellulose
d. glycogen; cellulose

A

b. amylose; amylopectin

101
Q 
Linear homopolysaccharide with β(14)
glycosidic bond
• Contains up to 5000 glucose units with
molecular mass of 900,000 amu
It serves as dietary fiber in food and readily
absorbs water resulting in softer stools
A

Cellulose

102
Q

Similar to cellulose structurally and functionally
• Linear polymer with all β(1->4) glycosidic
linkages
– It has an N-acetyl amino derivative of glucose
• Function is to give rigidity to the exoskeletons of
crabs, lobsters, shrimp, insects, and other
arthropods

A

Chitin

103
Q 
What is the structural component of plant cell
walls?
a. Starch
b. Glycogen
c. Chitin
d. Cellulose
A

d. Cellulose

104
Q

The Structure of Chitin

A

slide 112

105
Q

Polysaccharides with a repeating disaccharide
unit containing an amino sugar and a sugar with
a negative charge due to a sulfate or a carboxyl
group
• They are heteropolysaccharides, i.e., different
monosaccharides exist in an altering pattern

A

Acidic polysaccharides

106
Q

Examples of Acidic polysaccharides

A

Hyaluronic acid

Heparin

107
Q

Alternating residues of N-acetyl- β-Dglucosamine and D-glucuronate
• Highly viscous and serve as lubricants in the
fluid of joints as well as vitreous humor of the
eye

A

Hyaluronic Acid

108
Q

Polysaccharide with 15–90 disaccharide
residues per chain
• Blood anticoagulant

A

Heparin

109
Q

Heparin, a well known acidic polysaccharide, is
best known for its biochemical function as a(n)
_____.
a. coagulant
b. anticoagulant
c. exoskeleton
d. dietary fiber

A

b. anticoagulant

110
Q

Dietary
monosaccharides or disaccharides
Sweet to taste and commonly referred to as sugars

A

Simple carbohydrates

111
Q

Dietary
polysaccharides
– Include starch and cellulose, which are normally not
sweet to taste

A

Complex carbohydrates

112
Q 
Dietary carbohydrates constitute \_\_\_\_\_ of the diet
of most people.
a.10%
b.25%
c.35%
d.50%
A

d. 50%

113
Q

Lipid molecule that has one or more
carbohydrate (or carbohydrate derivative) units
covalently bonded to it

A

Glycolipid

114
Q

Protein molecule that has one or
more carbohydrate (or carbohydrate derivative)
units covalently bonded to it

A

Glycoprotein

115
Q 
A protein molecule that has one or more
carbohydrate units covalently bonded to it is
known as a(n) \_\_\_\_\_.
a. glycolipid
b. glucoprotein
c. glycoprotein
d. oligosaccharide protein
A

b. glucoprotein

116
Q

D-glucose consists of six carbon atoms. When drawn using the Fischer projection formula, how do you determine that it is the D isomer? How many chiral carbon centers does it have and how many stereoisomers are possible?

a. The –OH on the chiral carbon farthest from the carbonyl group points to the
right. There are five chiral centers providing 32 stereoisomers.

b. The –OH on the chiral carbon farthest from the carbonyl group points to the
right. There are four chiral centers providing 16 stereoisomers.

c. The –OH on the chiral carbon farthest from the carbonyl group points to the
left. There are five chiral centers providing 32 stereoisomers.

d. The –OH on the chiral carbon farthest from the carbonyl group points to the
left. There are four chiral centers providing 16 stereoisomers.

A

b. The –OH on the chiral carbon farthest from the carbonyl group points to the
right. There are four chiral centers providing 16 stereoisomers.

117
Q

Prior to a marathon run, an athlete consumes large amounts of complex carbohydrates to do what is known as “carbohydrate loading.”
What happens in the body to the glucose molecules present in these complex carbohydrates and why is carbohydrate loading important?

a. The complex carbohydrates are broken down to glucose and any excess glucose, not
used for immediate energy, is stored in the form of glycogen, which can be used later as
a source of stored energy.

b. The complex carbohydrates are broken down to glucose and any excess glucose, not
used for immediate energy, is stored in the form of starch, which can be used later as a
source of stored energy.

c. The complex carbohydrates are broken down to galactose and any excess galactose,
not used for immediate energy, is stored in the form of glycogen, which can be used later
as a source of stored energy.

d. The complex carbohydrates are broken down to glucose and any excess glucose, not
used for immediate energy, is stored in the form of glycogen, which can be used later to
produce muscle tissue needed to complete the marathon.

A

a. The complex carbohydrates are broken down to glucose and any excess glucose, not
used for immediate energy, is stored in the form of glycogen, which can be used later as
a source of stored energy.

Biochem (1 decks)

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