3. Organic substances composed of carbon, hydrogen and oxygen
Soluble in water
CLASSIFICATION
1. Monosaccharides (simple sugars)
2. disaccharides
3. Oligosaccharides
4. Polysaccharides (glycans)
4. The simplest units and can’t be hydrolyzed into simpler forms
CLASSIFICATION
Acc to no. of carbon atoms > triose, tetrose, pentose,hexose…
Acc to the “carbonyl” group
A. Aldo sugar : having an aldehyde group ex. Glucose or ribose
B. Keto sugar : having a ketone group ex. Fructose
Carbonyl group is C-1 in aldoses and C-2 in ketoses
5.
6. Monosaccharides of 5 or more carbon atoms are present in ring form
In “Howorth” configuration of the ring form, all groups to the right
of the carbon atom will be directed downward and all groups to its
left will be directed upward, except around C-5 where the reverse
occurs
Condensation of the carbonyl group with one of the alcohol groups of
the same sugar forms closed ring structure “pyran or furan”
Carbonyl group will be called “Anomeric” group in ring form and can
exist in two forms
α form with hydroxyl group to the right (down)
β form with hydroxyl group to the left (up)
7.
8. A carbon atom attached to 4 different atoms or groups
Compounds having one of those will have
1. Isomers : compounds having the same molecular weight and composition but
differ in their physical and chemical properties
2. Optical activity : when a beam of light passes in their solution it will be either
rotated to the right “dextrorotatory” or the left “levorotatory” D & L
9. Epimers : differ only around one carbon “not anomeric”
1. Glucose & mannose at C-2
2. Glucose & galactose at C-4
α & β anomers : differ around anomeric (ring form)
Aldo & keto isomers : differ in functional group “aldehyde & ketone”
1. Glucose and fructose
10.
11. 1. Sugar acids : oxidation product of monosaccharides “adding O”
Uronic acid > glucose gives glocuronic by oxidation of last carbon
2. Sugar alcohols (-itols) : reduction product of monosaccharides
“adding H2”
Glucose gives sorbitol by reduction of first carbon
3. Deoxy sugar : a hydroxyl group (OH) is replaced by a hydrogen
atom
2-Deoxy-ribose > component of DNA
4. Amino sugar : a hydroxyl group at C-2 is replaced by an amino
group (NH2)
Glucose gives glucosamine
12. Compounds formed of 2 monosaccharides (same or different) linked by glycosidic
bonds
1. Maltose : 2 D-glucose linked by α-1-4 glucosidic bond
2. Lactose : D-glucose & β-D-galactose linked by β-1,4-galactosidic bond
3. Sucrose : D-glucose & β-D-fructose linked by β-2,1-fructosidic =
α-1-2 glucosidic bond
13. Polymers of 10 or more mono Or their derivatives linked by
glycosidic bonds.
CLASSIFICATION
1. Homopolysaccharides (simple) : contain only one type of mono
ex. Glucosans > starch , glycogen , cellulose
fructosans > inulin
galactosans > agar agar
2. Heteropolysaccharides (mixed) : more than one type of mono
They mey be acidic (contain acid sugars) or neutral (contain sugars and amio sugars)
14. 1. Starch
storage form of carbs in plants and major source of it for animals
Each molecule is formed of 2 types of glucosans
Complete hydrolysis with
1. Acids : gives rise to free glucose units
2. Amylase : gives maltose as end product
Partial hydrolysis give rise to forms of dextrins ex. Erythro & amylodextrin
Amylose amylopectin
Inner part Outer
Straight chain of D-glucose linked
by α-1,4
Branched chain linked by α-1,4
except at branching point α-1,6
Gives blue color with iodine Red with iodine
15.
16. 2. Glycogen
Storage form of carbohydrates in animals .. Stored mainly in liver and muscles
Similar to amylopectin but more branched and compact
Pink with iodine
17. 3. Cellulose
Structural polysaccharide present in plants
Linear polymer of D-glucose linked by β-1,4-glucosidic bond
Not digested in man d.t absence of cellulose enzymes
18. They are compounds that relate directly or indirectly to fatty acids
They contain C, H, O ± P, N & S
They have common properties of being
1. Insoluble in water
2. Soluble in nonpolar solvents as ether and benzene
3. Associated with fatty acids and utilized by living organisms
IMPORTANCE
1. High caloric value= 9.3 Kcal/g
2. Organ coating
3. Thermal insulator
4. Cell membrane
20. They are esters of glycerol with various fatty acids
CLASSIFICATION OF FATTY ACIDS
1. Chain length
Short chain (low F.A) (2-10 F.A) ex. Acetic acid 2C ,butyric acid 4C
Long chain (high F.A) (>10 F.A) ex. Palmetic 16C ,stearic 18C
2. Saturation
Saturated (no double bonds) ex. butyric ,stearic
Unsaturated (double bonds)
Mono (one db) ex. Oleic acid 18:1;9 nervonic acid 24:1;15
Poly (>1 db) ex.leinoleic 18:2;9,12 arachidonic 20:4;,5,8,11,14
3. Biological importance
1. Essential F.A (polyunsaturated) : cant be synthesized in body
2. Non essential F.A (saturated or monounsaturated) synthesized in body from other
precursor
3. Relatively essential F.A (arachidonic) : synthesized n body only in presence of linoleic
21. Alcohol ?
organic compound in which the hydroxyl functional group (-OH) is bound to a carbon
atom (R3COH) , it is colorless and sweet
Ex. Glycerol sphignosine & cholesterol
Glycerol ?
a trihydric alcohol with 3 OH groups
Fatty acids ?
organic acids originating from hydrolysis of natural fats and oils
Aliphatic
Monocarboxylic
Even no. of C atoms
24. 1. PHOSPHOLIPIDS
They are membrane components amphipathic and ionic in nature
A. GLYCERO-P.L (having glycerol as their alcohol backbone)
The precursor is (glycerol-3-phosphate)
The fatty acids present are mostly saturated at R1 unsaturated at
R2
ex. Phosohatidic acid : simplest form and precursor for others with
no base
Phosphatydyl choline : most abundant present in cell membrane with
choline base
25. B. SPHIGNO-P.L (having sphignosine as their alcohol backbone)
Contain sphignosine instead of glycerol, a higher fatty acid,
phosphoric acid and a base
Important membrane component for animals and plants, they are
present in large amounts in brain and myelin of nerves
Sphignosine + saturated or unsaturated F.A = CERAMIDE
(the characteristic parent structure for sphignolipids)
26. 2. GLYCOLIPIDS (glyco-sphigno-lipids)
They are in every tissue of the body especially nervous .. They also
occur at outer leaflet of plasma membrane
A. NEUTRAL G.L (cerebrosides) :
They contain one or more neutral sugar molecules as their polar
head group .. The monosaccharide is bound to the OH of ceramide
Ex. Galactocerebroside glucocerebroside
They are concerned with
Cell communication and recognition
Tissue immunity
Species specificity
Bloog group antigens
B. ACIDIC G.L :
Ex. Cerebroside sulphate (sulphatides) : sulphate ester of galactocerebroside
gangliosides : neuraminoc acid in addition to glycosyl ceramide
28. STEROIDS
They have in common a cyclic ring called “steroid nucleus”
It is composed of 17 C with 2 methyl groups at C10 & C13
Steroids include
A. Sterols
B. Bile acids and salts
C. Steroid hormones
D. Vitamin D
29. It has a hydroxyl group (OH) at C3 and an aliphatic side chain at
C17 (Alcohol)
TYPES
1. Animal sterols :cholesterol and its derivatives (vit D3)
2. Plant sterols : ergosterol (pro vit D2) and its derivatives
30. I. Bile acids are hydroxyl derivatives of cholanic acid
It is obtained in the liver by oxidation of cholesterol at C24 with removal
of the last 3C
They are the end products of cholesterol catabolism in the body as it can
not break down steroid nucleus
II. Bile salts are products of conjugation of bile acids with amino
acids “glycine and taurine” in their sodium or potassium salts
