Carbohydrates Flashcards
1
Q
Study of the chemical
substances found in living organisms and the chemical interactions of these substances with each other
A
Biochemistry
2
Q
T/F. Carbohydrates account for 75% of dry plant material and are produced by photosynthesis
A
True
3
Q
Cellulose
A
Structural Element
4
Q
Starch/Glycogen
A
Energy/Reservoir
5
Q
In the process of photosynthesis, what enzymes are used to convert carbon dioxide, water, and solar energy to carbohydrates and oxygen?
A
Chlorphyll and plant enzymes
6
Q
Functions of Carbohydrates in Human Body
A
- ENERGY. Carbohydrate oxidation provides energy
- STORAGE. Carbohydrate storage, in the form of glycogen, provides a short-term energy reserve
- CARBON ATOMS. Carbohydrates supply carbon atoms for the synthesis of other biochemical substances
(proteins, lipids, and nucleic acids) - STRUCTURAL FRAMEWORK OF DNA N RNA. Carbohydrates form part of the structural framework of DNA and RNA molecules
7
Q
Carbohydrates linked to lipids are _________.
A
structural components of cell membranes
8
Q
Carbohydrates linked to protein function in a variety of
A
cell - cell and cell–molecule recognition processes
9
Q
Empirical Formula of Simple Carbohydrates
A
CnH2nOn (Cn(H2O)n)
10
Q
A polyhydroxy aldehyde, a polyhydroxy ketone, or a compound that yields polyhydroxy aldehydes or polyhydroxy ketones upon hydrolysis
A
Carbohydrates
11
Q
Striking feature of carbohydrates
A
Large number of functional group is present. A functional group is attached to each C-atom.
12
Q
Monosaccharide
A
+ Contain single polyhydroxy aldehyde or ketone unit
+ Cannot be broken down into simpler substances by hydrolysis reactions
13
Q
How many C-atoms in monosaccharides?
A
3 - 7 atoms
14
Q
Pure Monosaccharides physical appearance
A
Water soluble white, crystalline solids
15
Q
Monosaccharides examples
A
Glucose and Fructose
16
Q
Disaccharides
A
+ Contain 2 monosaccharide units covalently bonded to each other
+ crystalline and water soluble
+ upon hydrolysis = 2 monosaccharide units
17
Q
Common disaccharides
A
table sugar (sucrose)
milk sugar (lactose)
18
Q
Oligosaccharides
A
Contain three to ten monosaccharide units covalently bonded to each other
19
Q
T/F. Free oligosaccharides are often encountered in biochemical systems.
A
False. Always associated with proteins and lipids in complex molecules - structural and regulatory fxn
20
Q
Polysaccharide
A
a polymeric carbohydrate that contains many monosaccharide units covalently bonded to each other
21
Q
Polysaccharide number of units
A
few hundred to more than a million units (50, 000 sa ppt)
22
Q
Examples of Carbo
A
cellulose - paper, cotton, and wood
starch - bread, pasta, potatoes, and peas
23
Q
A form of isomerism
A
handedness
24
Q
Mirror Image
A
Reflection of an object in an mirror
25
Superimposable mirror images (achiral)
Images that coincide at all points when the images are laid upon each other
26
Other name for superimposable mirror images
achiral center
27
Nonsuperimposable mirror images (chiral)
images where not all points coincide when the images are laid upon each other
28
Nonsuperimposable mirror images other name
chiral molecule (handedness)
29
+ C atom attached to 4 different
groups
+ denoted by *
+ example bromochloroiodomethane
Chiral center
30
T/F. Both forms of handedness should be active.
False. One can be more active. One may be active and the other non-active. Both can be active
31
Monosaccharides handedness
right handed
32
Amino acids and proteins
left handed
33
Stereoisomers
Isomers that have the same molecular and structural formulas but differ in the orientation of atoms in space
34
Stereoisomers whose molecules are
non-superimposable mirror images of each other
Enantiomers
35
Diastereomers
Stereoisomers whose molecules are not mirror images of each other
36
Two-dimensional structural notation for showing the spatial arrangement of groups about chiral centers in molecules
Fischer Project Formula
37
Tetrahedral Arrangements. Vertical lines equates to
bonds directed into page
38
Tetrahedral arragnements, horizontal lines equates to
bonds directed out of the page
39
Used to designate the handedness of enantiomers
L and D system
40
Where is numbering of carbon chain in a D,L system?
Carbonyl Group end of the molecule
41
The chiral center number that determines the D or L configuration of monosaccharide
highest number
42
Epimers
Diastereomers whose molecules differ only in the configuration at one chiral center
43
How can you identify the D isomer of a carbohydrate by looking at the Fischer projection formula?
The –OH group on the chiral carbon farthest from the carbonyl group is pointing to the right
44
Isomers differ in chemical and physical properties - boiling and melting
Constitutional isomers
45
Isomers that differ in most chemical and physical properties - boiling and freezing point.
Diastereomers
46
Two Differences between Constitutional Isomers and Diastereomers
1. Their interaction with plane polarized light
2. Their interaction with other chiral substances
47
Ordinary light waves
vibrate in all directions
48
Plane polarized light waves
vibrate only in one direction
49
T/F. Direction and extent of rotation will depend upon the concentration of the enantiomer.
True
50
T/F. Same concentration of two enantiomers rotates light
to same extent and same directions.
False. Opposite Directions
51
Why are enantiomers optically active?
They can rotate the plane of polarized lights.
52
Dextrorotatory Compound (Rotation)
Chiral compound that rotates light towards right (clockwise +)
53
Levorotatory compound (rotation)
chiral rotates left (counterclockwise, -)
54
Enantiomeric pairs have same solubility in?
Achiral Solvents
55
Enantiomeric pairs have different solubility in?
Chiral solvents i.e. D-2-butanol
56
T/F. Enantiomers have same boiling points, melting points, and densities
True. Chirality does depend in IMFA
57
Isomer of epinephrine have higher response. 20 times greater!!
D isomer
58
Monosaccharides Classification basis
number of carbon atoms
59
3 carbon atoms monosaccharide
Triose
60
6 carbon atoms monosaccharides
Hexose
61
Monosaccharide with one aldehyde group
Aldose
62
Monosaccharide with one ketone group
Ketose
63
biochem important monosaccharides
- most abundant in nature
- most important source of human nutrition
- also named as grape sugar
- 6 membered cyclic form
D-glucose
64
Other names for D - glucose
Dextrose
Blood Sugar (70 - 100 mg/dL)
65
- Milk sugar
- synthesized in human beings
- also called brain sugar
- differentiate between blood types
- 6 membered cyclic form
D-galactose
66
- sweetest tasting of all sugars
- good dietary sugar due to higher sweetness
- 5 membered cyclic form
D-fructose
67
Also a ketohexose
D-fructose
68
A part of a variety complex molecules which include: RNA, ATP, DNA
- five membered
D-ribose
69
Cyclic structures of Monosaccharides are formed by
reaction between carbonyl group with hydroxyl group on carbon 5
70
Cyclic hemiacetal forms of Monosaccharide
All -OH groups to the right appear below the ring. All groups on the left appear above the ring.
71
2 forms of D-Glucose
alpha form
beta form
72
alpha form of D-glucose
where the –OH of C1 and CH2OH of C5 are on opposite sides
73
beta form of D-glucose
where the –OH of C1 and CH2OH of C5 are on the same side
74
a carbon that, in the acyclic form, is not a stereocenter, but once it takes on the cyclic form, it becomes a stereocenter
anomeric carbons
75
Anomers
Cyclic monosaccharides that differ only in the position of the substituents on the anomeric carbon atom
76
Aside from glucose, what carbohydrates can also be cyclize?
Fructose and other ketoses
77
Furanose
Cyclic monosaccharide containing a five-atom ring
78
an alcohol and ether attached to the same carbon
hemiacetal
79
Cyclic monosaccharide containing a six-atom ring
Pyranose
80
Two-dimensional structural notation that specifies the three-dimensional structure of a cyclic form of a monosaccharide
Haworth Projection Formula
81
Five important reactions of monosaccharides
– Oxidation to acidic sugars
– Reduction to sugar alcohols
– Glycoside formation
– Phosphate ester formation
– Amino sugar formation
82
T/F. Glucose will be used as the monosaccharide reactant
True
83
How many sugar types are yielded by oxidation?
3
84
Acidic Sugar Types
Aldonic
Aldaric
Alduronic
85
The carbonyl group in a monosaccharide (either
an aldose or a ketose) is reduced to a hydroxyl
group using hydrogen as the reducing agent.
Reduction to Produce Sugar alcohols
86
Used as a moisturizing agent in foods and cosmetics and as a sweetening agent in chewing
gum
Sorbitol
87
Acetal formed from a cyclic
monosaccharide by replacement of the hemiacetal carbon –OH group with an –OR group
Glycoside
88
Glycoside produced from glucose
Glucoside
89
Glycoside produced from galactose
Galactoside
90
Hydroxyl groups of a monosaccharide can react
with inorganic oxyacids to form inorganic esters
Phosphate Ester Formation
91
Phosphate esters of various monosaccharides stable in?
aqueous solution
92
formed when one of the hydroxyl groups of a monosaccharide is replaced with an amino group
Amino sugar
93
What carbon is replaced by the C2 carbon
Carbon 2
94
Important building blocks of polysaccharides i.e. chitin and hyaluronic acid
amino sugars , and N-acetyl derivatives
95
resulting ether bond of two monosaccharides reacting together
glycosidic linkage
one monosaccharide = hemiacetal
other = alcohol
96
Structurally made of 2 D-glucose units, one of which must be α-D-glucose, linked via an α(1 to 4) glycosidic linkage
Maltose
97
Baby foods are rich in
Malt sugar
98
Produced as an intermediate in the hydrolysis of the polysaccharide cellulose
cellobiose
99
Contains two D-glucose monosaccharide units, one
of which must have a β configuration, linked through
a β(14) glycosidic linkage
cellobiose
100
disaccharides cannot be digested by humans
cellobiose
101
Made up of β-D-galactose unit and a D-glucose unit joined by a β(1 to 4) glycosidic linkage
Lactose
102
Lactose in human mother's milk
7 - 8%
103
Cow's milk lactose
4% - 5%
104
a condition in which
people lack the enzyme lactase needed to hydrolyze lactose to galactose and glucose
Lactose intolerant
105
the most abundant of all disaccharides found in plants
Sucrose
106
Produced commercially from the juice of sugar cane and sugar beets
Sugar
107
Sugar beets percentage of sucrose
17%
108
Sugar cane percentage of sucrose
20%
109
T/F. Sucrose is a nonreducing sugar.
True
110
Carbohydrates that contain 3–10 monosaccharide units bonded to each other via
glycosidic linkages
- commonly found in onions, cabbage, broccoli, an whole wheat
Oligosaccharides
111
Made of 1 galactose, 1 glucose, and 1 fructose
Raffinose
112
Made of 2 galactose, 1 glucose, and 1 fructose units
Stachyose
113
The basis for difference in blood types present
- responsible for blood groups and D-galactose and its derivatives
Oligosaccharides
114
a potato plant toxin, is a
oligosaccharide found in association with an
alkaloid
- causes bitter taste in potato
Solanine
115
Polysaccharides are polymers of many monosaccharide units bonded with glycosidic
linkages
Polysaccharides
116
Types of polysaccharides
homopolysaccharides
heteropolysaccharides
117
Characteristics of Polysaccharides
Polysaccharides are not sweet and do not show positive tests with Tollen’s and Benedict’s solutions. Limited water solubility
118
examples of polysaccharides
cellulose and glycogen
chitin
hyaluronic acid
119
Polysaccharide that is
a storage form for monosaccharides and used
as an energy source in cells
Storage polysaccharides
120
- Unbranched-chain polymer and accounts for 15%–
20% of the starch
– Has α (1to 4) glycosidic bonds
Amylose
121
– Branched chain polymer and accounts for 80%–85%
of the starch
– Has α(14) and α(16) glycosidic bonds
– Up to 100,000 glucose units are present
– Amylopectin is digested more readily by humans (can
hydrolyze α linkages but not β linkages)
Amylopectin
122
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
Acidic polysaccharides
123
Dietary
monosaccharides or disaccharides
- sweet
- 20% of energy in US diet
simple carbohydrates
124
complex carbohydrates
dietary polysaccharides
– Include starch and cellulose, which are normally not sweet to taste
125
Lipid molecule that has one or more carbohydrate (or carbohydrate derivative) units
covalently bonded to it
glycoplipid
126
Protein molecule that has one or more carbohydrate (or carbohydrate derivative)
units covalently bonded to it
- important in cellular functions
glycoproteins
