Module 08: Carbohydrates (Stoker) Flashcards
1
Q
This is the study of the chemical substances found in living organisms and the chemical interactions of these substances with each other
A
Biochemistry
2
Q
This is a chemical substance found within a living organism
A
biochemical substance
3
Q
This form of biochemical substance are comprised of water and inorganic salts.
A
Bioinorganic substances
4
Q
This form of biochemical substance are comprised of carbohydrates, lipids, proteins, and nucleic acids
A
Bioorganic substances
5
Q
How many percentage of dry plant material is produced by photosynthesis?
A
75%
6
Q
This is the structural element of carbohydrates?
A
Cellulose
7
Q
This is the energy reservoir of the body and is present in small amounts.
A
Starch/glycogen
8
Q
The average human diet contains how many carbohydrates?
A
2/3 of carbohydrates
9
Q
Carbohydrates are also known as what
A
Saccharides (is perceived as the most abundant bioorganic molecules on Earth)
10
Q
How are carbohydrates produced?
A
Produced by photosynthesis
11
Q
What is the general formula of carbohydrates?
A
(CH2O)n (n≥3)
12
Q
What are the functions of carbohydrates?
A
(1) Carbohydrate oxidation - provides energy
(2) Carbohydrate storage, in the form of glycogen, provides a short-term energy reserve
(3) Carbohydrates supply carbon atoms for the synthesis of other biochemical substances (proteins, lipids, and nucleic acids)
(4) Carbohydrates form part of the structural framework of DNA and RNA molecules
(5) Carbohydrates linked to lipids (Chapter 19) are structural components of cell membranes
(7) Carbohydrates linked to proteins (Chapter 20) function in a variety of cell–cell and cell–molecule recognition processes
13
Q
When integrated with lipids, carbohydrates act as “_________________-“
A
structural components of cell membranes
14
Q
When integrated with proteins, carbohydrates act as “_________________-“
A
function in a variety of cell–cell and cell–molecule recognition processes
15
Q
What is the simpler formula of carbohydrates?
A
CnH2nOn or Cn(H2O)n (hydrates of C), where n pertains to the number of atoms
16
Q
In plants, these serve as structural elements in the cell wall of plants
A
Cellulose
17
Q
in plants, these serve as energy reserve for plants
A
Starch
18
Q
Carbohydrates are classified as either what?
A
polyhydroxy aldehydes or ketones
19
Q
How do some carbohydrates produce such substances?
A
Hydrolysis
20
Q
These contain single polyhydroxy aldehyde or ketone unit. They cannot be broken down into simpler substances by hydrolysis (reaction with water) reactions
A
Monosaccharide
21
Q
How many carbon atoms do Monosaccharides contain?
A
Contains 3 to 7 C atoms, where 5 and 6 carbon species are more common
22
Q
How are Monosaccharides classified?
A
They are water-soluble white crystalline solids
23
Q
What are examples of Monosaccharides?
A
Glucose and Fructose
24
Q
These contain 2 monosaccharide units and are classified to be more common and are also crystalline water soluble substances.
A
Disaccharides
24
What do Disaccharides form when hydrolyzed?
2 monosaccharide units
25
These are generic examples of Disaccharides?
Table sugar (sucrose) and milk sugar (lactose)
26
In the human body, Disaccharides function as what?
In human body, Disaccharides are associated with proteins and lipids for structural and regulatory functions
27
These contains 2 to 10 monosaccharide units that are covalently bonded to each other
Oligosaccharides
28
These contains many monosaccharide units that are covalently bonded.
Polysaccharides
29
These Polysaccharides may contain 100s of 1000s of monosaccharide units.
Polymers
30
These are generic examples of Polysaccharides?
Cellulose and Starch
31
Most monosaccharides exist in two forms:
(1) Left-handed
(2) Right-handed
32
These types of objects are defined as images that coincide at all points when the images are laid upon each other
Superimposible on their mirror images (achiral)
33
These types of objects are characterized to be Chiral (handedness).
Non-superimposable on their mirror images
34
How do you define a chiral center?
C atom attached to 4 different groups (A molecule with chiral center is a chiral molecule )
35
How do you classify chirality?
(1) Best way to visualize - look at all C atoms and see if there are at least two H atoms then that can’t be a chiral center
(2) C atoms with less than one H atoms are worth looking at for their chirality
(3) similarity and difference of groups
36
Why is 3-bromopentane achiral?
C has two CH2-CH3 groups – so it is achiral
37
What are the responses of Left and Right Handed Forms of a Molecule in a Human Body?
(1) Both may be active, one may be more active or one may be active and other non-active
Example: Right handed hormone epinephrine is 20 times more active than left handed form
(2) Almost all monosaccharides are right handed
(3) Amino acids are almost always left handed
38
Where are Monosaccharides derived from?
Derived from CO2 and H2O by photosynthesis
39
How are Monosaccharides classified?
(A( their carbonyl group: aldehydes (aldose) or ketones (ketose)
(B) the number of C (trioses, tetroses, pentoses, hexoses, heptose)
(C) According to configuration – D or L sugar
40
This is known as the smallest aldose.
Glyceraldehyde
41
This is known as the smallest ketose
Dihydroxy-acetone
42
How many chiral carbons does aldohexose d-glucose have?
four (4) chiral carbons
43
These have the same absolute configuration at the asymmetric center farthest away from their carbonyl group as does D-glyceraldehyde (i.e., C5 in D glucose).
D sugars
44
How many asymmetric center does Glyceraldehyde have?
one asymmetric center
45
How did Emil Fischer propose spatial isomers (Stereoisomers)?
In 1892, Emil Fisher proposed that the spatial isomers (stereoisomers), of glyceraldehyde be designated D- and L-glyceraldehyde. Fisher assigned the D and L to the above structures of glyceraldehyde, but it was not until 1949 that experiments confirmed that his guess was correct.
46
What do D-isomers denote?
D indicates rotation to the right
47
What do L-isomers denote?
L indicates rotation of polarized light to the left. The L sugars are the mirror images of their D counterparts
48
This pertains to the monosaccharide with an aldehyde group on C1
Aldose
49
This pertains to the monosaccharide with a keto group on C2
Ketose
50
These are isomers that have the same molecular and structural formulas but differ in the orientation of atoms in space.
Stereoisomers
51
These are stereoisomers whose molecules are nonsuperimposable mirror images of each other. Molecules with chiral center.
Enantiomers
52
These are stereoisomers whose molecules are not mirror images of each other.
Diastereomers
53
This is a method for giving molecular chirality specifications in two dimensions
Fischer projection formulas
54
How are Fischer projection formulas characterized?
This is a two-dimensional structural notation for showing the spatial arrangement of groups about chiral centers in molecules.
55
In a Fischer projection formula, how is a chiral center (Carbon) represented?
as the intersection of vertical and horizontal lines
56
In a Fischer projection formula, D and L system are used to what
D and L system used to designate the handedness of glyceraldehyde enantiomers can be extended to other monosaccharides with more than one chiral center
57
These has four groups attached to the atom at the chiral center
tetrahedral geometry (Tetrahedral Arrangements)
58
In Tetrahedral Arrangements, what do vertical arrangements represent?
represent bonds to groups directed into the printed page.
59
In Tetrahedral Arrangements, what do horizontal arrangements represent?
represent bonds to groups directed out of the printed page
60
Where should one start numbering a carbon chain?
starting at the carbonyl group end of the molecule
61
What is used to determine D or L configuration?
highest-numbered chiral center
62
These are diastereomers whose molecules differ only in the configuration at one chiral center
Epimers
63
How do Constitutional isomers and Diastereomers differ?
in most chemical and physical properties.(boiling points and melting points)
64
How are enantiomers different?
(1) Their interaction with plane polarized light
(2) Their interaction with other chiral substances
65
In this property of light, these form light move in all directions
Ordinary (unpolarized) Light
66
In this property of light, these form light move in same (comparable) and in one direction.
Plane polarized Light
67
How is a Plane polarized Light rotated?
Plane polarized light is rotated clockwise (to right) or counterclockwise (to left) when passed through enantiomers (Direction and extent of rotation will
depend upon the enantiomer)
68
How do same concentration of two enantiomers rotate?
rotate light to same extent but in opposite direction (optically active)
69
This is a chiral compound that rotates light towards right (clockwise; +)
Dextrorotatory
70
This is a chiral compound that rotates light towards left (counterclockwise; -)
Levorotatory
71
How are D and L as well as + and - determined, respectively?
Structure and by using a polarimeter
72
How is the solubility of achiral solvents enantiomeric pairs characterized?
Enantiomeric pairs have same solubility in achiral solvents like ethanol
73
How is the solubility of chiral solvents enantiomeric pairs characterized?
Enantiomeric pairs have different solubility in chiral solvent like D-2-butanol
74
The comparable (similar) boing points melting points, and densities of enantiomers are dependent on what
intermolecular forces and chirality doesn’t depend on them
75
This classification of monosaccharides contains three carbon atoms.
Triose
76
This classification of monosaccharides contains four carbon atoms.
Tetrose
77
This classification of monosaccharides contains five carbon atoms.
Pentoses
78
This classification of monosaccharides contains six carbon atoms.
Hexoses
79
This is a monosaccharide with aldehyde group and 6 C atoms
D-Glucose (Aldohexose)
80
This is a monosaccharide with ketone group and 6 C atoms
D-Fructose (Ketohexose)
81
This is an optimal source of glucose.
Grape fruit, grape sugar, dextrose, and blood sugar (70 - 100 mg/100 mL of blood)
82
This is the most abundant in nature and is nutritionally most important
Glucose
83
How much glucose can be obtained from grapefruit?
20-30% by mass
84
Glucose is characterized as a What?
Six membered cyclic form )Aldohexose)
85
This is the sweetest tasting of all sugars, found in many fruits and in honey is also perceived as a good dietary sugar due to higher sweetness
Fructose
86
fructose is characterized as a What?
Six membered cyclic form Ketohexose)
87
This is known as the milk sugar and is synthesized by humans. It is also utilized to differentiate between blood types.
Galactose
88
Galactose is also known as "__________-"
brain sugar (part of the brain and nerve tissue)
89
Galactose is characterized as a What?
Six membered cyclic form )Aldohexose)
90
Ribose is a part of what?
(1) ATP
(2) DNA
(3) RNA
91
Ribose is characterized as a What?
Five membered cyclic form (Aldopentose)
92
This is the dominant form of monosaccharides with 5 or more C atoms.
Cyclic Hemiacetal Forms of D-Glucose
93
How are cyclic forms in equilibrium?
cyclic forms are in equilibrium with open chain form
94
How are cyclic forms formed (generated)?
Cyclic forms are formed by the reaction of carbonyl group (C=O) with hydroxyl (-OH) group on carbon 5
95
What is the alpha form of d-glucose?
Alpha-form: -OH of C1 and CH2OH of C5 are on opposite sides
96
What is the beta form of d-glucose?
OH of C1 and CH2OH of C5 are on same sides
97
What kind of isomerism is observed in aldose and ketose pair?
Functional isomers-
98
What are some examples of epimers?
glucose and mannose, glucose and galactose
99
How does D-glucose and D-Mannose differ?
epimer at C2
100
How does D-Glucose and D-Galactose?
epimer at C4
101
All aldoses with five or more carbon atoms establish similar equilibria, but with different percentages of the _______________.
alpha, beta, and open-chain forms.
102
This pertains to a cyclic monosaccharide containing a six-atom ring
Pyranose
103
This pertains to a cyclic monosaccharide containing a five-atom ring
Furanose
104
This is a two-dimensional structural notation that specifies the three-dimensional structure of a cyclic form of a monosaccharide
Haworth projection formula
105
How is alpha and beta configuration determined?
Alpha or Beta configuration is determined by the position of the —OH group on C1 relative to the CH2OH group that determines D or L series.
106
How are the positions of the OH group on C1 relative to the CH2OH group in the Beta Configuration?
both of these groups point in the same direction
107
How are the positions of the OH group on C1 relative to the CH2OH group in the Alpha Configuration?
the two groups point in opposite directions.
108
How is the specific identity of a monosaccharides determined?
by the positioning of the other —OH groups in the Haworth projection formula.
109
How is the OH group at a chiral center that is to the right in a Fischer projection formula pointed in the Haworth projection?
Down
110
How is the OH group at a chiral center that is to the left in a Fischer projection formula pointed in the Haworth projection?
Up
111
What are the five most important reactions of monosaccharides?
Oxidation to acidic sugars
Reduction to sugar alcohols
Glycoside formation
Phosphate ester formation
Amino sugar formation
112
What are examples of aldonic acids?
Benedict’s, Fehling’s, Barfoeds and Tollens reagent
113
This form of oxidation to sugar acids involve enzymes/
alduronic acid
114
This form of oxidation to sugar acids involve a strong oxidizing agent (HNO3)-
aldaric acid
115
The redox chemistry of monosaccharides in terms of the oxidation of acidic sugar is closely linked to what? .
the alcohol and aldehyde functional groups present in them
116
Weak oxidizing agents such as Tollens and Benedict’s solutions oxidize what?
oxidize the aldehyde end to give an aldonic acid.
117
This is a carbohydrate that gives a positive test with Tollens and Benedict’s solutions.
reducing sugar
118
What can a reducing sugar do?
A reducing sugar reduces the oxidizing agent and is oxidized to an acid.
119
How can Monosaccharides be oxidized>
Monosaccharides can be oxidized by weak oxidizing agents such as Cu2+ ions.
120
What kind of acid is d-gluconate?
aldonic acid
121
What is oxidized by strong oxidizing agents?
Strong oxidizing agents like concentrated nitric acid can oxidize both ends of a monosaccharide at the same time (the carbonyl group and the terminal primary alcohol group)
122
What is produced upon oxidizing both ends of a monosaccharide at the same time (the carbonyl group and the terminal primary alcohol group)?
dicarboxylic acid:
123
Aldaric acids are known as "_______________"
polyhydroxy dicarboxylic acids
124
How is alduronic acid produced
In biochemical systems enzymes can oxidize the primary alcohol end of an aldose such as glucose, without oxidation of the aldehyde group, to produce an alduronic acid.
125
How are sugars reduced?
The carbonyl group in a monosaccharide (either an aldose or a ketose) is reduced to a hydroxyl group using hydrogen as the reducing agent.
126
What is the product of the reduction to sugar alcohols?
The product is the corresponding polyhydroxy alcohol
127
This is used as moisturizing agents in foods and cosmetics and as a sweetening agent in chewing gum
Sorbitol
128
Cyclic forms of monosaccharides are called "___________"
hemiacetals (they react with alcohols to form acetals)
129
Monosaccharide acetals are called "______________"
glycoside
130
How are glycosides formed?
A glycoside is an acetal formed from a cyclic monosaccharide by replacement of the hemiacetal carbon —OH group with an —OR group:
For example:
A glycoside produced from glucose - glucoside
A glycoside produced from galactose – galactosidase
131
What are the four blood types?
A, B, AB, and O:
132
What happens when the wrong blood is transfused?
A transfusion of wrong blood type can cause the blood cells to form clumps - a potentially fatal reaction.
133
They are universal donors.
People with type O blood
134
They are universal recipients.
People with type AB blood
135
What are the most common blood types in the United States?
In the United States type O blood is the most common and type A the second most common.
136
What is the biochemical basis for various blood types?
The biochemical basis for the various blood types involves monosaccharides present on plasma membranes of red blood cells.
137
What is the importance of monosaccharides in blood groups?
The monosaccharides responsible for blood groups are D-galactose and its derivatives.
138
What is formed when the hydroxyl groups of a monosaccharide react with inorganic oxyacids to form inorganic esters?
Phosphate ester
139
When are Phosphate ester stable?
When they are in aqueous solution and play important roles in the metabolism of carbohydrates.
140
These are important building blocks of polysaccharides such as chitin
Amino sugars and their N-acetyl derivatives
141
One monosaccharide can act as what?
hemiacetal and other as alcohol
142
This is produced as an intermediate in the hydrolysis of the polysaccharide cellulose:
Cellobiose
143
Cellobiose contains what?
two b - D-glucose monosaccharide units linked through a b (1—4) glycosidic linkage.
144
Why can't cellobiose be digested properly?
Because humans do not have enzymes that can break (1-4) linkages of cellobiose
145
This is digested easily by humans because we have enzymes that can break a (1-4) linkages
Maltose
146
Lactose is made up of what?
b-D-galactose unit and a b-D-glucose unit joined by a b(1-4) glycosidic linkage
147
This is the principal carbohydrate in milk.
Lactose
148
How much lactose constitutes humans?
7%–8% lactose
149
How much lactose constitutes cow's milk?
- 4%–5% lactose
150
This is a condition in which people lack the enzyme lactase needed to hydrolyze lactose to galactose and glucose.
Lactose intolerance
151
This hydrolyzes b(1-4) glycosidic linkages.
Lactase
152
What causes the Deficiency of lactase?
Deficiency of lactase can be caused by a genetic defect, physiological decline with age, or by injuries to intestinal mucosa.
153
What happens when lactase is not digested properly?
it attracts water causing fullness, discomfort, cramping, nausea, and diarrhea. Bacterial fermentation of the lactose further along the intestinal tract produces acid (lactic acid) and gas, adding to the discomfort
154
This is the most abundant of all disaccharides and found in plants. It is produced commercially from the juice of sugar cane and sugar beets.
Sucrose (table sugar):
155
How much sucrose does sugar cane contain?
20% by mass
156
How much sucrose does sugar beet contain?
17% by mass sucrose
157
These are formed from monosaccharide units bonded with glycosidic linkages
Polymers
158
What are the two types of polymer chain?
Linear and branched, homo- and hetero-polysaccharides
159
Why don't Polysaccharides show positive tests with Tollen’s and Benedict’s solutions?
They are not sweet and they have limited water solubility.
160
What are some examples of Polysaccharides?
Cellulose, starch in plants
Glycogen in animals
Chitin in arthropods
161
Glucaric acid is characterized as what "____________-"
water soluble
162
Galactaric acid is characterized as what "____________-"
nonpolar due to symmetry (water insoluble).
163
What is the basis of mucic acid test used to differentiate glucose from galactose.
polarity and solubility
164
This sugar acid is related to the Oxidation of the aldehyde group of aldoses
Aldonic acids
165
This sugar acid is related to the Oxidation of the primary alcohol group of aldoses
alduronic acids
166
This sugar acid is related to the Oxidation of both with concentrated HNO3
aldaric acid
167
what kind of acid is d-gluconic acid?
Aldonic acids
168
What kind of acid is d-glucuronic acid?
Alduronic acid
169
What kind of acids are glucaric and Galactaric acid
Aldaric acid
170
These are known as sugar alcohols. These are known as sweeteners in chewing gum and accumulates in the lens of diabetics resulting to cataracts
Glucitols
171
How can an aldehyde group or keto group be reduced?
The aldehyde group or keto group can be reduced to a 1o alcohol or 2o alcohol using H2 as reducing agent.
172
What occur predominantly as a cyclic structures?
aldotetroses and all monosaccharides with n ≥ 5
173
How are cyclic hemiacetals and cyclic hemiketals formed?
Alcohol groups can react with the aldehydes or ketones (The hydroxyl and either the aldehyde or the ketone of monosaccharides can react intramolecularly to form cyclic hemiacetals and hemiketals)
174
what are intramolecular hemiacetal formation?
Sugars with ≥ 5 C mostly exist in their cyclic form (Since C1 becomes a chiral center, there are two new possible stereoisomers that are named a and b)
175
These isomeric forms that differ only in their configuration about the hemiacetal or hemiketal carbon atom. ⇒ a, b anomers
Anomers
176
This is the hemiacetal carbon atom or the new chiral C.
anomeric carbon
177
How is the anomeric carbon formed?
Cyclic sugars have 2 anomeric forms. During cyclization, the carbonyl carbon becomes a chiral center and is called, the anomeric carbon with two possible configurations.
178
How do Disaccharides arise?
They arise through the formation of O-glycosidic bonds: condensation of anomeric carbon hydroxyl group with an alcohol.
179
How is lactose formed
condensation of a molecule of β-D galactopyranose with a molecule of D-glucose (a or b) through β-I,4- glycosidic linkage.
180
How is sucrose formed?
the condensation of a molecule of a-D-glucopyranose with a molecule of β-D-fructofuranose through α-1,2-glycosidic bond
181
What is the monomer and linkage of maltose respectively?
Two a-D-GLUCOSE and a-1,4-GLYCOSIDIC
182
What is the monomer and linkage of lactose respectively?
B-D GALACTOSE and a-D-GLUCOSE and b-1,4-GLYCOSIDIC
183
What is the monomer and linkage of sucrose respectively?
a-D-FRUCTOSE and a-D-GLUCOSE and b-1,2-GLYCOSIDIC
184
What is the monomer and linkage of cellobiose respectively?
Two b-D-GLUCOSE and b-1,4-GLYCOSIDIC
185
What is the monomer and linkage of isomaltose respectively?
Two a-D-GLUCOSE and a-1,6-GLYCOSIDIC
