Lecture 1
Transcript
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1. CarbohydratesDr. Khalid Hussain
2. Introduction• Chemically: Polyhydroxy aldehydes and ketones• Have hydrogen and
oxygen in a ratio of water (2:1) Ribose (C5H10O5) and Glucose (C6H12O6)
3. • General formula Cn(H2O)n.Hence, also called hydrates of carbon• Substances which
are converted into polyhydroxy aldehydes and ketones after hydrolysis
4. Importance of carbohydrates• Provide major source of energy (4.1C)• Serve also as
stored forms of energy as glycogen in liver and muscles• Protein sparing action• Reduce
breakdown of fatty acids and preventing ketosis• Involved in biological recognition
processes of immunoglobulin
5. Contn’d• Flavoring and Sweetening agents• Dietary fiber (Cellulose)• Important
components of brain cells as neuraminic acids, cerebrosides (Glycolipids) and
gangliosides• Important component of nucleic acids as pentose sugars - ribose and
deoxyribose
6. Contn’d• Function as physiological anticoagulant (Heparin)• Plasma expanders
(Dextran)• Parenteral nutrition• Binders in tablets• Disintegrators in tablets• Analytical
techniques: Agar agar and starch• Diagnostic markers
7. Classification• Have been classified into 4 main groups – Monosaccharides –
Disaccharides – Oligosaccharides – Polysaccharides
8. Monosaccharides• Carbohydrates which can’t further be broken down into simpler
units by acid hydrolysis• Classified according to the number of carbon atoms present in
them – For example trioses, tetroses and hexoses
9. • Usually have 3-9 carbon atoms• Further sub-classified into aldoses and ketoses•
Exact name is based on – number of carbons atoms – presence of aldehyde or ketone
groups – i.e aldotriose or ketotriose
10. Aldotrioses/ C3 H 6 O 3 Glyceraldehyde and dihydroxyketotrioses
acetoneAldotetroses/ C4 H 8 O 4 Erythrose, ErythruloseketotetrosesAldopentoses/
C5H10O5 Ribose , RibuloseketopentosesAldohexoses/ C6H12O6 Glucose,
Fructoseketohesoses Erythrose Ribose Ribulose
11. • Monosaccharides also include derivatives of above mentioned monosaccharides e.g.
amino sugars, sugar alcohols, sugar acids and esters of sulfuric acid and phosphoric acid
12. Disaccharides• Biose• Formed when two monosaccharides undergo a condensation
reaction which involves the elimination of a small molecule, such as water, from the
functional groups only Sucrose
13. Oligosaccharides• Greek word oligos, meaning "a few", and sacchar which means
"sugar“• Saccharide polymers containing a small number (typically three to ten) of
component sugars- Monosaccharides For example Raffinose
14. Polysaccharides• Polymeric carbohydrate structures, formed by repeating units (either
mono- or di- saccharides) joined together by glycoside bond• Such structures are often
linear, but may contain various degrees of branching• Polysaccharides are often quite
heterogeneous, containing slight modifications of the repeating unit
15. • When all the monosaccharides in a polysaccharide are of same type the
polysaccharide is called a homopolysaccharide: starch and glycogen, but when more than
one type of monosaccharides are present, they are called heteropolysaccharides: pectin,
Lecture 1
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lignin• Polysaccharides have a general formula of (C6H10O5)n• Not sweet, hence called
non-sugars
16. CH2OH 6CH OH CH2OH CH2OH CH2OH 2 O 5 O H O H O H H O HH H H H H
H H H H H OH H 1 4 OH H 1 OH H OH H OH H O O O O OHOH 2 3 H OH H OH H
OH H OH H OH amylose CH2OH 6CH OH CH2OH CH2OH CH2OH 2 O 5 O O H O H
O OH H H H H H H H H OH H 1 O 4 OH H 1 O OH H O OH H O OH H OH H H H H 2
H 3 H OH H OH H OH H OH H OH cellulose Upon acid hydrolysis produce
monosaccharides
17. Significance• Key role in maintaining energy balance in the biosphere• Building
blocks and source of energy• Used as excipients in Dusting Powders, disintegrant,
mucilage• Bio-markers• Aspharmaceuticals Medicine –heparin, glucose, dextran etc.•
Chromatography and electrophoresis
18. Oxidation of glucose• Mild oxidizing agents such as bromine water convert glucose
to gluconic acid, which is single step reaction• This reaction is used to differentiate
sugars having – CHO (reducing) group or those yielding such group
19. Example is Fehlings solution test• Fehlings solution is composed of equal parts of
two solutions:1-Fehlings solution A 69.28 grams copper sulfate pentahydrate dissolved in
1 litre of distilled water2-Fehlings Solution B 346 grams potassium sodium tartrate and
120 grams sodium hydroxide in 1 litre of distilled water
20. Fructose also give positive test• Under alkaline conditions fructose is converted to
glucose and mannose
21. Tollens reagent test "silver mirror"• Tollens reagent: when silver nitrate solution is
treated with sodium hydroxide(NaOH) till it forms precipitate and then NH4OH is added
till the precipitate is dissolved- Ag(NH3)2]+• The diammine silver complex is an
oxidizing agent, which is itself reduced to silver metal
Transcript







1. CarbohydratesDr. Khalid Hussain
2. Introduction• Chemically: Polyhydroxy aldehydes and ketones• Have hydrogen and oxygen in
a ratio of water (2:1) Ribose (C5H10O5) and Glucose (C6H12O6)
3. • General formula Cn(H2O)n.Hence, also called hydrates of carbon• Substances which are
converted into polyhydroxy aldehydes and ketones after hydrolysis
4. Importance of carbohydrates• Provide major source of energy (4.1C)• Serve also as stored
forms of energy as glycogen in liver and muscles• Protein sparing action• Reduce breakdown of
fatty acids and preventing ketosis• Involved in biological recognition processes of
immunoglobulin
5. Contn’d• Flavoring and Sweetening agents• Dietary fiber (Cellulose)• Important components
of brain cells as neuraminic acids, cerebrosides (Glycolipids) and gangliosides• Important
component of nucleic acids as pentose sugars - ribose and deoxyribose
6. Contn’d• Function as physiological anticoagulant (Heparin)• Plasma expanders (Dextran)•
Parenteral nutrition• Binders in tablets• Disintegrators in tablets• Analytical techniques: Agar
agar and starch• Diagnostic markers
7. Classification• Have been classified into 4 main groups – Monosaccharides – Disaccharides –
Oligosaccharides – Polysaccharides
Lecture 1














8. Monosaccharides• Carbohydrates which can’t further be broken down into simpler units by
acid hydrolysis• Classified according to the number of carbon atoms present in them – For
example trioses, tetroses and hexoses
9. • Usually have 3-9 carbon atoms• Further sub-classified into aldoses and ketoses• Exact name
is based on – number of carbons atoms – presence of aldehyde or ketone groups – i.e aldotriose
or ketotriose
10. Aldotrioses/ C3 H 6 O 3 Glyceraldehyde and dihydroxyketotrioses acetoneAldotetroses/ C4 H
8 O 4 Erythrose, ErythruloseketotetrosesAldopentoses/ C5H10O5 Ribose ,
RibuloseketopentosesAldohexoses/ C6H12O6 Glucose, Fructoseketohesoses Erythrose Ribose
Ribulose
11. • Monosaccharides also include derivatives of above mentioned monosaccharides e.g.
amino sugars, sugar alcohols, sugar acids and esters of sulfuric acid and phosphoric acid
12. Disaccharides• Biose• Formed when two monosaccharides undergo a condensation reaction
which involves the elimination of a small molecule, such as water, from the functional groups
only Sucrose
13. Oligosaccharides• Greek word oligos, meaning "a few", and sacchar which means "sugar“•
Saccharide polymers containing a small number (typically three to ten) of component sugarsMonosaccharides For example Raffinose
14. Polysaccharides• Polymeric carbohydrate structures, formed by repeating units (either
mono- or di- saccharides) joined together by glycoside bond• Such structures are often linear,
but may contain various degrees of branching• Polysaccharides are often quite heterogeneous,
containing slight modifications of the repeating unit
15. • When all the monosaccharides in a polysaccharide are of same type the polysaccharide is
called a homopolysaccharide: starch and glycogen, but when more than one type of
monosaccharides are present, they are called heteropolysaccharides: pectin, lignin•
Polysaccharides have a general formula of (C6H10O5)n• Not sweet, hence called non-sugars
16. CH2OH 6CH OH CH2OH CH2OH CH2OH 2 O 5 O H O H O H H O HH H H H H H H H H H OH H 1
4 OH H 1 OH H OH H OH H O O O O OHOH 2 3 H OH H OH H OH H OH H OH amylose CH2OH 6CH
OH CH2OH CH2OH CH2OH 2 O 5 O O H O H O OH H H H H H H H H OH H 1 O 4 OH H 1 O OH H O
OH H O OH H OH H H H H 2 H 3 H OH H OH H OH H OH H OH cellulose Upon acid hydrolysis
produce monosaccharides
17. Significance• Key role in maintaining energy balance in the biosphere• Building blocks and
source of energy• Used as excipients in Dusting Powders, disintegrant, mucilage• Bio-markers•
Aspharmaceuticals Medicine –heparin, glucose, dextran etc.• Chromatography and
electrophoresis
18. Oxidation of glucose• Mild oxidizing agents such as bromine water convert glucose to
gluconic acid, which is single step reaction• This reaction is used to differentiate sugars having –
CHO (reducing) group or those yielding such group
19. Example is Fehlings solution test• Fehlings solution is composed of equal parts of two
solutions:1-Fehlings solution A 69.28 grams copper sulfate pentahydrate dissolved in 1 litre of
distilled water2-Fehlings Solution B 346 grams potassium sodium tartrate and 120 grams sodium
hydroxide in 1 litre of distilled water
20. Fructose also give positive test• Under alkaline conditions fructose is converted to glucose
and mannose
21. Tollens reagent test "silver mirror"• Tollens reagent: when silver nitrate solution is treated
with sodium hydroxide(NaOH) till it forms precipitate and then NH4OH is added till the
Lecture 1
precipitate is dissolved- Ag(NH3)2]+• The diammine silver complex is an oxidizing agent, which is
itself reduced to silver metal
+