Carbohydrate Chemistry (ppt) Flashcards
1
Q
Functions of Carbohydrates
A
- SOURCE
- INTERMEDIATES
- ASSOCIATED
- FORM
- PARTICIPATE
2
Q
Simple sugars
A
MONSACCHARIDES
3
Q
Simplest sugar
A
Trioses:
D-GLYCERALDEHYDE (Aldose)
DIHYDROXYACETONE (Ketose)
4
Q
Is a carbon atoms attached to 4 different groups
A
CHIRAL CARBON (ASYMMETRIC CARBON)
5
Q
All monosaccharides have chiral carbon except?
A
DIHYDROXYACETONE
6
Q
Reference sugar
A
GLYCEROSE(GLYCERALDEHYDE)
7
Q
the —OH group on this carbon is on the right
A
D ISOMER
8
Q
the —OH group on this carbon is on the left
A
L ISOMER
9
Q
Most of the naturally occurring monosaccharides are?
A
D SUGARS
10
Q
Non mirror isomers
A
DIASTEREOISOMERS
11
Q
Mirror image isomers
Ex: D-fructose and L-fructose
A
ENANTIOMERS
12
Q
The presence of asymmetric carbon atoms also confers optical activity on the compound.
When a beam of plane-polarized light is passed through a solution of an optical isomer, it rotates either to the right, dextrorotatory (+), or to the left
A
OPTICAL ISOMERISM
13
Q
-
A
DEXTROROTATORY (+)
14
Q
-
A
LEVOROTATORY (-)
15
Q
Measurement of optical activity in chiral or asymmetric molecules using plane polarized light
A
POLARIMETRY
16
Q
Are the middle asymmetric carbons other than the subterminal one
Isomers differing as a result of variations in configuration of the —OH and —H on carbon atoms 2, 3, and 4 of glucose
Two sugars that differ only in the configuration around one carbon atom
A
EPIMERS
17
Q
Important epimer of glucose
A
MANNOSE (epimerized in carbon 2)
GALACTOSE (epimerized in carbon 4)
18
Q
A six membered ring
A
PYRAN
19
Q
A five-membered ring
A
FURAN
20
Q
These are isomeric forms of monosaccharides that differ only in their configuration about the hemiacetal or hemiketal carbon atom
A
ANOMERS
21
Q
It is the carbonyl carbon atom
A
Anomeric carbon
23
Q
These are ring structure formed by combination of an aldehyde/ketone into an alcohol group
A
HEMIACETAL/ HEMIKETAL
24
Q
Simple ring in perspective conformational representation
A
HAWORTH PROJECTION
25
Q
Straight chain representation
A
FISCHER PROJECTION
26
Process where CHO change spontaneosuly between the and configurations through the formation of intermediate open chain.
MUTAROTATION
27
Used to identify sugars
Monosaccharides reacting with phenylhydrazine
A crystalline compound with a sharp melting point and a characteristic shape is obtained
OSAZONE FORMATION
28
D-fructose and D-mannose give the same _ as D-glucose
NEEDLE SHAPE OSAZONE CRYSTALS
29
3 Types of acid formed when aldoses where oxidized:
ALDONIC ACID
URONIC ACID
SACCHARIC ACID
30
Aldehyde group is converted to a carboxyl group
Examples:
Glucose – Gluconic acid, Galactose-Galactonic acid and Mannose- Mannonic acid
ALDONIC ACID
31
Aldehyde is left intact and primary alcohol at the other end is oxidized to COOH
Examples:
Glucose --- Glucuronic acid
Galactose --- Galacturonic acid
Mannose-----Mannuronic acid
URONIC ACID
32
Oxidation at both ends of monosaccharide
Examples:
Glucose ---- Gluco saccharic acid
Galactose --- Mucic acid
Mannose --- Mannaric acid
SACCHARIC ACID (GLYCARIC ACID)
33
-
REDUCTION
34
Resultant product when a sugar is reduce
POLYOL (SUGAR ALCOHOL)
GLUCOSE - GLUCITOL
MANNOSE - MANNITOL
FRUCTOSE - MANNITOL AND SORBITOL
GLYCERALDEHYDE - GLYCEROL
35
Monosaccharides are normally stable to dilute acids, but are dehydrated by?
STRONG ACIDS
36
D-ribose when heated with concentrated HCl yields?
FURFURAL
37
Forms the basis of Molisch test, Seliwanoff test and Bial’s Test
DEHYDRATION OF STRONG ACIDS ON MONOSACCHARIDES.
38
Highly reactive sugars
Powerful reducing agents
Allows interconversion of D-mannose, D-fructose and D-glucose
ENEDIOLS
39
Interconversion reaction of D-mannose, D-fructose and D-glucose
LOBRY DE BRUYN-VAN ECKENSTEIN TRANSFORMATION
40
This happens when sugar is reacted to strong alkalis (decomposition)
CARAMELISATION
41
Enediols obtained by the action of bases are quite susceptible to oxidation when heated in the presence of an oxidising agent. It forms the basis of _ for the detection of reducing sugars
BENEDICT’S AND FEHLING’S TEST
42
Frequently used as the oxidising agent and a red precipitate of Cu2O is obtained
COPPER SULFATE
43
Sugars which give a reaction with copper sulfate and forming a red precipitate of Cu2O.
REDUCING SUGARS
44
Fehling’s solution
KOH or NaOH and CuSO4
45
Benedict’s solution
Na2CO3 and CuSO4
46
They are formed by replacing the hydroxyl group (at C2 usually) of monosaccharides by amino group
AMINO SUGARS
47
The most common amino sugars
GLUCOSAMINE and GALACTOSAMINE
48
Amino sugar present in Heparin, Hyaluronic acid and blood group substances
GLUCOSAMINE
49
Amino sugar present in Chondroitin of cartilages and tendons.
GALACTOSAMINE
50
The amino group may be condensed with active acetate forming?
They are components of glycosaminoglycans and some glycosphingolipids (lipids)
Component of CHITIN
N-ACETYL GLUCOSAMINE
51
Amino sugar that is a component of glycoproteins and gangliosides(Lipids) of cell membrane.
N-ACETYL MANNOSAMINE
52
Component of Chondroitin sulphate.
N-ACETYL GALACTOSAMINE
53
Amino sugar acids are produced by?
CONDENSATION OF AMINO SUGAR WITH PYRUVIC OR LACTIC ACID
54
Amino sugar acid produced by the condensation of lactic acid with D- Glucosamine
MURAMIC ACID
55
An amino sugar acid that is formed from the condensation of pyruvic acid with N-Acetyl Mannosamine
N-AACETYL NEURAMINIC ACID
56
Sugars that are formed by removal of an oxygen atom usually from 2nd carbon atom
DEOXY SUGARS
57
Deoxy sugar is which is the sugar found in DNA
2’-DEOXY RIBOSE
58
A deoxy sugar used as a fermentative reagent in bacteriology
6-DEOXY-L-MANNOSE (L-RHAMNOSE)
59
Are formed by the oxidation of aldehyde C1(Aldonic acid)
- or terminal hydroxyl group at C6 of aldose sugar(uronic acid)
- or both (saccharic) to form carboxylic group.
- Glucuronic and Iduronic acids are the components of glycosaminoglycans.
- L-ascorbic acid(vitamin C) is a sugar acid.
SUGAR ACIDS
60
A sugar acid involved in detoxification of bilirubin and other foreign compounds.
GLUCURONIC ACID
61
Are formed by the reduction of the carbonyl group (aldehyde or ketone) of monosaccharide
SUGAR ALCOHOLS
62
```
Give the reduction form of the following sugars into sugar alcohol:
Glucose
Mannose
Fructose
Galactose
Ribose
```
```
Respectively:
SORBITOL
MANNITOL
SORBITOL/ MANNITOL
DULCITOL/ GALACTITOL
RIBITOL (Vitamin B2)
```
63
Hydroxyl groups of sugars can be esterified to form Acetates, phosphates, benzoates etc.
Sugars are phosphorylated at terminal C1 hydroxyl group or at other places
At terminal hydroxyl: Glucose-6-Phosphate or Ribose-5-Phosphate
SUGAR ESTERS
64
Metabolism of sugars inside the cell starts with?
PHOSPHORYLATION
65
Also components of nucleosides and nucleotides.
SUGAR PHOSPHATES
66
Formed by the reaction of the -OH group of anomeric carbon (hemiacetal or hemiketal) with the hydroxyl group of any other molecule with the elimination of water.
A glycosidic bond is formed.
GLYCOSIDES
67
These include derivatives of digitalis and strophanthus such as oubain.
CARDIAC GLYCOSIDES
68
A glycoside that is use as an antibiotic
STREPTOMYCIN
69
A glycoside that displaces Na+ from the binding sites of “carrier protein” and prevents the binding of sugar molecule and produces glycosuia
PHLORIDZINE
70
Sugars composed of two monosaccharide residues link by glycosidic bond
DISACCHARIDES
71
Formed by joining of 2 glucose units by alpha-1,4 glycosidic bond
- O-α-D-glucopyranosyl-(1->4)- α -D-glucopyranose
Produced by partial hydrolysis of starch either by Salivary or Pancreatic amylase
Fermentable sugar
Used as nutrient as a sweetener and as a fermentative reagent
Has a free active group and hence exhibits reducing properties, mutarotation and α-β isomerism.
MALTOSE (MALT SUGAR)
72
Composed of 2 glucose units linked by alpha-1,6 glycosidic linkage
Produced by enzymatic hydrolysis of starch (at the
ISOMALTOSE
73
Non reducing sugar
O-α-D-glucopyranosyl-(1->2)-β-D-fructofuranoside
-the configuration of this glycosidic linkage is α for glucose and β for fructose.
No free reactive group (because the anomeric carbons of both monosaccharides units are involved in the glycosidic bond)
Neither shows reducing properties nor mutarotation characters
Invert sugar
SUCROSE (TABLE SUGAR)
74
Hydrolytic product of Sucrose is called? Because the optical activity of sucrose ( dextrorotatory) is inverted after hydrolysis [by an acid or an enzyme (invertase or sucrase)] into equimolar mixture of its two components glucose (+52.5) and fructose (-92.5) and the optical activity of the mixture becomes levorotatory.
INVERT SUGAR
75
Enzyme that cleave sucrose into its component monosaccharides
SUCRASE
76
Galactose + Glucose via β (1,4) glycosidic linkage
Sugar of milk
Syntesized in the mammary glands during lactation
Milk contains the alpha and beta anomers in a 2:3 ratio
Used in infant formulations, medium for penicillin production and as diluent in pharmaceuticals
LACTOSE
77
Is sweeter and more soluble than ordinary α - lactose
BETA LACTOSE
78
Enzyme that catalyze the hydrolysis of lactose to its monosaccharide components.
```
LACTASE (Human)
BETA GALACTOSIDASE (Bacteria)
```
79
Deficiency of lactase enzyme that is manifested by diarrhea, abdominal cramps, bloating and distension
LACTOSE INTOLERANCE
80
Composed of beta-galactose and beta-fructose in a beta-(1,4) glycosidic bond
Semi-synthetic disaccharide
Osmotic laxative
Management of portal systemic encephalopathy
Use to lower the high ammonia content i chronic liver disease
LACTULOSE
81
O-alpha-D-glucopyranosyl-1->)-alpha-D-glucopyranoside
Found in yeast and fungi
The main sugar of insect hemolymph
Non reducing in nature due to lack of free functional group
TREHALOSE
82
-
OLIGOSACCHARIDES
83
Trisaccharide
| Glucose + Galactose + Fructose
RAFFINOSE
84
Tetrasaccharide
| 2 Galactose + Glucose + Fructose
STACHYOSE
85
Pentasaccharide
| 3 Galactose + Glucose + Fructose
VERBASCOSE
86
Hexasaccharide
| 4 Galactose + Glucose + Fructose
AJUGOSE
87
Sugar constituent of honey
MELEZITOSE
88
A break down product of starch useful in chromatographic separation
CYCLOHEPTAMYLOSE (HEPETASACCHARIDE)
89
Characteristics:
```
Polymers (MW from 200,000)
White and amorphous products (glassy)
Not sweet
Not reducing; do not give the typical aldose or
ketose reactions
Form colloidal solutions or suspensions
```
POLYSACCHARIDE/ GLYCAN
90
2 Types of Polysaccharides:
HOMOGLYCANS
| HETEROGLYCANS
91
Examples of Homoglycans:
```
💡💡
G
S
C
G
F
I
```
GLUCOSANS:
Starch
Cellulose
Glycogen
FRUCTOSAN:
Inulin
GALACTOSAN
Agar
92
Example of Heteroglycans:
MUCOPOLYSACCHARIDES
93
These are polymers composed of a 💡single type of sugar monomers
Homopolysaccharides/ Homoglycans
94
Also known as 💡animal starch
Stored in 💡muscle and liver
Present in cells as granules (high MW)
Contains both 💡α(1,4) links and 💡α(1,6) branches at every 8 to 12 glucose unit
Complete hydrolysis yields glucose
With iodine gives a 💡red-violet color
Hydrolyzed by both α and 💡β-amylases and by 💡glycogen phosphorylase
Serves as a 💡buffer to maintain blood glucose level.
GLYCOGEN
95
The concentration of glycogen is __ in the liver than in muscle (10% versus 2% by weight), but more glycogen is stored in skeletal muscle overall because of its much greater mass.
HIGHER
96
It is the most common storage polysaccharide in 💡plants
Composed of 10 – 30% Amylose and 70-90% amylopectin depending on the source
STARCH
97
A linear polymer of α-D-glucose, linked together by 💡α 1→4 glycosidic linkages.
It is soluble in water, reacts with iodine to give a 💡blue color and the molecular weight of ranges between 50,000 – 200,000.
AMYLOSE
98
A highly branched polymer, 💡insoluble in water, reacts with iodine to give a 💡reddish violet color. The molecular weight ranges between 70,000 - 1,000,000.
Branches are composed of 💡25-30 glucose units linked by 💡α 1→4 glycosidic linkage in the chain and by 💡α 1→6 glycosidic linkage at the branch point.
AMYLOPECTIN
99
Examples of storage polysaccharide:
STARCH
GLYCOGEN
INULIN
100
Suspensions of Amylose in water adopt a __.
HELICAL CONFORMATION
101
It can insert in the middle of the Amylose helix to give a 💡blue color that is characteristic and diagnostic for starch
IODINE
102
Produced by the 💡partial hydrolysis of starch along with maltose and glucose
Used as 💡mucilages (glues)
Used in 💡infant formulas (prevent the curdling of milk in baby’s stomach)
Used as 💡thickening agents in food processing.
DEXTRINS
103
Dextrins are often referred to as either;
Amylodextrins
Erythrodextrins
Achrodextrins
104
Products of the reaction of glucose and the enzyme 💡transglucosidase from Leuconostoc mesenteroides
Contains 💡α (1,4), 💡α(1,6) and 💡α (1,3) linkages
Used as 💡plasma expanders (treatment of shock)
Used as 💡molecular sieves to separate proteins and other large molecules (gel filtration chromatography)
Components of 💡dental plaques
DEXTRANS
105
Polymer of β-D-glucose linked by 💡β(1,4) linkages
Yields glucose upon complete hydrolysis
Partial hydrolysis yields 💡cellobiose
Most 💡abundant of all carbohydrates
Gives no color with iodine
Cellulose is tasteless, odorless and insoluble in water and most organic solvents.
Cannot be hydrolyze by mammals because it lacks the enzyme that hydrolyzes the 💡β 1→ 4 bonds
It is an important source of "bulk" in the diet, and the major component of dietary fiber.
CELLULOSE
106
It is used as binder-disintegrant in tablets
Microcrystalline cellulose
107
Suspending agent and bulk laxative
Methylcellulose
108
Hemostat
Oxidized cellulose
109
Laxative
Sodium carboxymethyl cellulose
110
rayon; photographic film; plastics
Cellulose acetate
111
enteric coating (capsules)
Cellulose acetate phthalate
112
explosives; collodion (pyroxylin)
Nitrocellulose
113
Examples of Structural Polysaccharide
CELLULOSE
| CHITIN
114
The second most abundant carbohydrate polymer of 💡N- Acetyl Glucosamine
Present in the 💡cell wall of fungi and in the 💡exoskeletons of crustaceans, insects and spiders
Used commercially in coatings (extends the shelf life of fruits and meats)
CHITIN
115
💡β-(1,2) linked fructofuranoses
Linear ,no branching
Lower molecular weight than starch
Colors yellow with iodine
Hydrolysis yields 💡fructose
Sources include onions, garlic, dandelions and Jerusalem artichokes
Used as diagnostic agent for the evaluation of 💡glomerular filtration rate (renal function test)
INULIN
116
Uses of Inulin:
```
💡💡
G
DF
AS
LGIS
F/C S
```
```
Used clinically as a highly accurate measure of
glomerular filtration rate (GFR)
Used as a soluble dietary fiber
Used as appetite suppressant
Used as a low glycemic index sweetener
Also used as a fat/cream substitute
```
117
A 💡galactose polymer
Obtained from the cell walls of some species of 💡red algae or seaweeds (Sphaerococcus Euchema ) and species of Gelidium
Dissolved in hot water and cooled, agar becomes gelatinous;
Its chief use is as a 💡culture medium for microbiological work. Other uses are as a 💡laxative,
A 💡vegetarian gelatin substitute,
A thickener for soups, in jellies, ice cream and Japanese desserts, As a clarifying agent in brewing, and for sizing fabrics.
AGAR
118
Are carbohydrates containing a repeating disaccharide
The disaccharide usually contains an acid sugar and an amino sugar.
Acid sugar is generally 💡D- Glucuronic acid or its 💡C-5 epimer Iduronic acid, while amino sugar is either 💡D- Glucosamine or 💡D-Galactosamine, amino group is generally acetylated eliminating its positive charge.
The amino sugar may be sulfated on non acetylated nitrogen.
Carboxyl groups of acid sugars together with sulfate groups give Glycosaminoglycans 💡strongly negative nature.
Heteropolysaccharides/ Mucopolysaccharides/ Glycosaminoglycans
119
Occurrence: synovial fluid, ECM of loose connective tissue.
Serves as a lubricant and shock absorber.
Only GAG that 💡does not contain any sulfate and is 💡not found covalently attached to proteins.
It forms non-covalently linked complexes with Proteoglycans in the ECM.
Are very large (100 - 10,000 kDa) and can displace a large volume of water.
Hyaluronic acid (💡D-glucuronate + GlcNAc)n
120
skin, blood vessels, heart valves
💡(L-Iduronate + GalNAc sulfate)n
Dermatan sulfate
121
Occurrence: cartilage, tendons, ligaments, heart valves and aorta.
It is the 💡most abundant GAG.
💡(D-glucuronate + GalNAc sulfate)n
Chondroitin sulfate
122
Component of intracellular granules of mast cells lining the arteries of the lungs, liver and skin
Contrary to other GAGs that are extra cellular compounds, it is intracellular.
💡(D-glucuronate sulfate + N-sulfo-D-glucosamine)n
Acts as an 💡anticoagulant.
Heparin
123
Occurrence: cornea, bone, cartilage;
They are often aggregated with Chondroitin sulfates.
💡(Gal + GlcNAc sulfate) n
Keratan sulfate
124
Found in 💡Pneumococci capsule
Act as 💡blood group substances.
Four monosaccharides , Galactose, Fucose, Galactosamine(Acetylated) and Acetylated Glucosamine are present in all types of blood group substances.
Also found in egg protein- ovalbumin
Neutral Mucopolysaccharides
125
Formed of 💡glycosaminoglycans (GAGs) covalently attached to the 💡core proteins.
Found in all connective tissues, extracellular matrix (ECM) and on the surfaces of many cell types.
Remarkable for their 💡diversity
Proteoglycans (mucoproteins)
126
A Proteoglycan monomer found in cartilage consists of a __
core protein to which the linear GAG chains are covalently linked.
127
The proteoglycan monomers associate with a molecule of Hyaluronic acid to form __
Bottle brush
Proteoglycan aggregates
128
Biophysical functions of Proteoglycans:
```
💡💡
C ECM
I CE
T ECM
B
L
CM
GFR
AC
SS
TC
```
Act as constituent of extracellular matrix or ground substance
Interact with collagen and Elastin
Contribute turgor to ECM acting as polycations and attracting water.
Act as barrier in the tissues
Act as lubricant in the joints
Help in the release of hormones
Help in cell migration in embryonic tissues
Present in the basement membrane of glomerulus of kidney, play important role in the Glomerular filtration
Heparin acts as an anticoagulant .
Heparin helps in the release of lipoprotein lipase, also called ‘Clearing factor’.
Components of cell membrane, act as receptors.
Chondroitin sulfates and hyaluronic present in cartilages have a great role in compressibility of cartilage in weight bearing
Maintain shape of sclera
Help in maintaining the transparency of cornea
129
Biochemical functions of Proteoglycans:
Participate in cell and tissue development and physiology.
130
D-glucose when heated with concentrated HCl yields?
5-HYDROXYMETHYLFURFURAL
