Chemistry Of Carbohydrates Flashcards
1
Q
Functions of carbohydrate
A
Storage form of energy (starch and glycogen
Source of energy
Excess carbohydrates are stored as fat
Carbohydrates are structural components of bio membrane e.g glycoproteins and glycolipid
Serves as structural basis of many organism, cellulose of plant, exoskeleton of insects, cell wall of micro organisms
2
Q
What serves as ground substance in higher organism
A
Mucopolysaccharides
3
Q
What are carbohydrates
A
They are polyhydroxyl ketone or aldehyde
4
Q
Glucose can be used to synthesize what
A
The cellulose of the plant cell walls
5
Q
What are carbohydrates
A
Carbohydrates are aldehyde or ketone derivatives of polyhydric alcohols
6
Q
Classifications of carbohydrates
A
Monosaccharides
Disaccharides
Oligosaccharides
Polysaccharides
7
Q
What are monosaccharides
A
Monosaccharides are sugas that can’t be hydrolyzed into simper carbohydrates
8
Q
Classification of monosaccharides
A
Based on number of carbon atoms (trioses, tetroses, pentoses, hexoses, hepptoses)
Based on the aldehyde or ketone group(Aldoses, ketoses)
9
Q
Functions of polyhydric alcohols
A
They are bulk sweeteners, with low caloride content,(weight reduction and diabetics)
10
Q
Reactions of monosaccharides
A
Mutorotation
Reducing properties
Formation of osazone with phenylhydrazine.
11
Q
Enediol formation
A
In mild alkaline solution, carbohydrates containing a free sugar group (aldehyde or ketone) will tautomerise to form enediol
12
Q
What happens in enediol formation
A
Two hydroxyl group are attached to the double bonded carbon atom
13
Q
What happens in enediol formation
A
Two hydroxyl group are attached to the double bonded carbon atom
14
Q
In mild alkaline condition, glucose is converted to what
A
Fructose and mannose
15
Q
The inter conversion of sugars through a common enediol form is called what
A
Lobry de bruyn _van Ekenstein formation
15
Q
The inter conversion of sugars through a common enediol form is called what
A
Lobry de bruyn _van Ekenstein formation
16
Q
Sugars are powerful reducing agents in what medium
A
Alkaline medium
17
Q
When oxidizing agents like cupric ions are present sugar forms what
A
A mixture of carboxylic acids by breaking at the double bond
18
Q
Use of Benedict’s reagent
A
To test for the presence of glucose in urine . I.e diagnosing diabetes mellitus
19
Q
What does Benedict’s reagent contain
A
It contains sodium cirate
Sodium carbonate
Copper sulphate
20
Q
What happens to sugar in alkaline medium
A
Enediol are formed
Cupric ion is reduced
Sugar is oxidized
21
Q
What are reducing sugars
A
They are sugars with free aldehyde or ketone group e.g glucose, fructose
22
Q
Osazone formation
A
All reducing sugars will react with excess of phenylhydrazine at boiling temperature
23
Q
Uses of osazone
A
Used to differentiate sugars in urine and other biological fluid
24
Physical form of osazone
They are needle_shaped crystal like
25
The difference in glucose fructose and mannose are dependent on what
The first and second carbon atom
26
Furfural derivatives
Monosaccharides when treated with concentrated sulphuric acid undergo dehydration with the removal of 3 molecules of water
27
Hexoses plus concentrated sulphuric acid
Hydroxylmethyl furfural
28
Pentose+ con sulphuric acid
It gives furfural
29
Furfural derivatives can condense with phenolic compounds to give what
Colored products, this forms the basis of Molisch test
30
Glucose iss reduced to what with reducing agents
Sorbitol
31
Mannose is reduced to what
Mannitol
32
Fructose is reduced to what
Sorbitol and mannitol
33
Galactose is reduced to
What
Dulcito
34
Ribose is reduced to what
Ribitol
35
What is a glycoside
When the hemi acetal group( the hydroxyl group of an anime tic
36
Stereoisomers
Compounds having the same structural formula but different spatial configuration
37
Asymmetrical carbon atom
It means that 4 different groups are attached to the carbon atom
38
Glyceraldehyde/glycerose has how many assymetric carbon
Have a single assymetric carbon
39
The number of possible stereoisomers depends on what
The number of assymetrical carbon atoms
40
Optical activity
The presence of assymetric carbon atom
41
When a beam of polarized light is passed through a carbon atom
It would rotate the light either to the left or right
42
D glucose is what
Deoxyrotatory
43
D fructose
Levorotatory
44
D and L isomerism of glucose
With respect to the penultimate carbon atom :C5, as in glucose, the configuration of OH and H groups is changed and two mirror images are formed
45
Diasteroisomers of glucose
Configurations changes with regard to C2, C3 and C4 will produce 8 different monosaccharides , though only 3 are found in the body
46
D glucose is also called
Dextrose
47
Galactose is a constituent of
Lactose(milk sugar ) and glycoproteins
48
Galactose is epimerized to what
Glucose in the liver and then utilized as fuel
49
Mannose is a consistent of what
Many glycoproteins
It was isolated from plant mammals, hence its name
50
What are diastomers
Are non mirror images , non identical isomers
51
Epimers
When sugar are different from one another , only in configuration with regard to a single carbon atom, other than the reference carbon atom
52
Glucose and mannose are epimers
With respect to carbon 2
53
Galactose and glucose are epimers with regards to
Carbon 4
54
Galactose and mannose are what
Diassteroisomers
55
Mutorotation
Change in rotation with time
56
What causes mutorotation
The fact that D glucose has 2 anomers, alpha and beta derivatives
57
Oxidation of sugars
Under mild oxidation conditions(hypobromus acid) , aldehyde group is oxidized to carboxyl group to form aldonic acid
58
When aldehyde group is protected and the molecule is oxidized
The last carbon becomes COOH group to produce uronic acid
59
Functions of glucuronic acids
It is used by the body in conjugation with insoluble molecules to make them soluble in water for detoxification purposes
Also for synthesis of Herero polysaccharides
60
Under strong oxidation conditions ( nitric acid + heat)
The first and last carbon atoms are oxidized to form dicarboxylic acid
61
Another name for dicarboxylic acid is
Saccharin acids
62
Furfural derivatives
Monosaccharides when treated with concentrated sulphuric acid undergo dehydration with the removal of 3 molecules of water
63
Reaction of hydrogen with reducing agents such as sodium amalgam
Reduces sugar
64
Reduction of aldose and ketose
Aldose yields corresponding alcohol
Ketose forms 2 alcohol because of appearance of a new assymetric carbon atom in this process
65
Glucose is reduced to
Sorbitol
66
Mannose is reduced to
Mannitol
67
Fructose is reduced to
Sorbitol and mannitol
68
Galactose is reduced to
Dorcitol
69
Functions of sorbitol mannitol and dulcitol
Used to identify bacteria colonies
70
Mannitol
Is used to reduce intercranial tension by forced diuresis
71
Osmotic effect of sorbitol and dulcitol produces changes where
In tissue when they accumulate in abnormal amounts e.g cataract of lens
72
Glycoside
When the hemiacetal group( hydroxyl group of an anomeric carbon) of a monosaccharide is condensed with an alcohol or phenol group
73
The non carbohydrate group of a glycoside
Aglycone
74
Why do glycosides not reduce Benedict's reagent
The sugar group is masked
75
Anomers of carbohydrates
Alpha and beta varieties
76
Anomers are produced by spatial configuration with reference to
First carbon atom in aldose
Second carbon In ketose
77
An anomer
Is an epimer at the hemiacetal and hemiacetal carbon in a cyclic saccharide
78
Specific rotation of alpha d_glucose
+112
79
Specific rotation of beta d glucose
+19
80
Differences between alpha and beta anomeric forms are dependent on
The first carbon atom only
81
Glucose has how many stereoisomers
16, each has 2 anomers and hence there are a total of 32 isomers of glucose
82
How is a glucose ring formed
The first carbon aldehyde is condensed with the hydroxyl group of the 5th carbon to form a ring
83
The ring structure represents what
Hemiacetal form, which is the condensation of an aldehyde group with a hydroxyl group
84
Open chain form of glucose
Glucose has an open in branched backbone of 6 carbon atom
85
Glucose exists in biological systems has
A pyramided ring
86
Structure of glucose
Beta and alpha d_ glucopyranose
Glucofuranose
87
Predominant form of glucose in solution
Beta D glucopyranose
88
Keto group in fructose
2nd carbon atom
89
Isomers of fructose
It has 4 isomers
Each having a d and l form in regard to penultimate carbon atom
90
Structure of fructose
Furs nose ring structure
91
Fructose is a major constituent of what
Honey
92
Number of diastereoisomers for aldohexoses
8
93
Reactions of monosaccharides
Mutorotation
Reducing property
Osazone formation with phenylhydrazine
Enediol formation
Benedict's reaction
Oxidation
Reduction to form alcohols
Furfural derivatives
94
The interconversion of sugars through a common enediol is called
Lovey de bruyn van ekenstein formation
95
Functions of osazone
May be used to differentiate sugars in biological fluids like urine
96
Oxidation of sugars
Under mild oxidation conditions, hypobromous acid) the aldehyde group is oxidized to carboxyl group to produce aldonic acid
97
When the aldehyde group is protected during oxidation
The last carbon becomes COOH and uldonic acid is formed
98
What happens during strong oxidation conditions
Nitric acid + heat
The first and last carbon atoms are oxidized to di carboxylic acids known as saccharin acids
99
Furfural derivatives of hexoses
Hydroxymethyl furfural
Pentose gives furfural
100
Disaccharides
When 2 monosaccharides are combined together by glycosidic linkage
101
Examples of disaccharides
Sucrose
Lactose
Isomaltose
Maltose
102
Sucrose
It is a sweetening agent known as cane sugar
It is present in sugar cane and other fruits
103
Sucrose contains
Glucose and fructose
104
Properties of sucrose
It is not a reducing sugar
It will not form osazone
When sucrose is hydrolyzed the products have reducing properties
105
Hydrolysis of sucrose
Rotation of + 65 would produce one molecule of glucise(+52.5) and one molecule of fructose (92 degrees
Changing the dextrororation to levorotation
106
The enzyme producing hydrolysis of sucrose
Sucrase or invertase
107
What does honey contain
Invert sugar
It is sweeter than sucrose
108
What produces isomaltose
Partial hydrolysis of glycogen and starch
109
Starch is composed of what
Amylose and amylopectin
110
Amylose
When starch is treated in boiling water
10_20 % is solubilized this part is amylose
It is made up of glucose units with alpha 1,4 glycosidic linkages to form an ynbranched long chain with a weight of 400,000 d or more
111
Amylopectin
The insoluble part abosorbs water and forms paste like gel
It is highly branched
Has one million molecular weight
Branching points are mad by alpha 1,6 linkage
112
Examples of heteroglycans
Hyaluronic acid
Chondriotin sulfate
113
What type of sugar is starch
It is a non reducing sugar
114
Starch's reaction with iodine
It would form a blue colored complex
115
When starch is hydrolyzed by mild acid
Amylodextrin is formed( it gives a violet color)
116
Further hydrolysis produces
Erythrodextrin
117
Erythrodextrin is what color
Red
118
End product of starch hydrolysis
Maltodextrins
Glucose
Fructose
Maltose
119
Action of amylases on starch
Alpha _maltose
120
Beta amylase are of plant origin
Yes
121
Beta amylase split starch to form what
Beta maltose
122
The action of beta amylase stops at branching points , leaving a large molecule called
Limit dextrin or residual dextrin
123
What Is the reserve carbohydrate in animals
Glycogen
124
Glycogen is stored where
In liver and muscle
125
Glycogen is composed of glucose molecules joined by
Alpha 1,4 links in straight chains
And alpha 1,6 links at the branching points
126
Glycogen contains a primer protein called
Glycogenin
127
Difference between glycogen and amylopectin
Glycogen is more branched and compact
128
Supporting tissues of plant
Cellulose
129
Cellulose link
It is made of glucose units combined with beta 1,4 glycosidic linkages
130
Enzymes in cellulose
Cellulose has only straight chains
It's bridges are hydrolyzed by the enzyme Cellobiase
131
Inulin
It is a long chain homoglycan composed of D fructose units with repeating beta 1,2 linkages.
132
Where is inulin found
It is found in various bulbs and tubers
133
Functions of inulin
It is used to find renal clearance value and glomerular filtration rate
134
Dextrans
Are highly branched homopolymers of glucose units with 1_6 , 1-4, and 1_3, linkages
135
What produces dextrans
Microorganisms
136
Uses of dextrans
For intravenous infusion
Used to treat hypervolemic shock
137
Chitin
It is present in exoskeleton of Crustacea and insects
138
Chitin is composed of units of
N acetyl_ glucosamine with beta 1,4 glycosidic linkages
139
Heteroglycans
Agar and Aagarose
Mucopolysaccharides
Glycoproteins and mucoproteins
140
Agar is prepared from
Sea weeds
141
Agar contains
Galactose, glucose and other sugars
142
When agar dissolves in water at 100
It sets into gek
143
Mucopolysaccharides are also called
Glycosaminoglycans
144
Constituents of mucopolysaccharides
Uronic acid and amino sugars
145
Examples of mucopolysaccharides
Hyaluronic acid
Heparin
Chondriotin sulphate
Keratan sulphate
Dermatan sulphate
146
Heparin activates what
Thrombomin 3
