1.
-Carbohydrates are the most abundant organic molecules in nature.
-Carbo-Hydrates means “Hydrates of carbon.” also called saccharides, which
means “sugars.”
-Carbohydrates are defined as polyhydroxyaldehydes or polyhydroxyketones or
compounds which produce them on hydrolysis.
-Composed of -carbon Sulphur, Nitrogen or Phosphorus
hydrogen
oxygen
CARBOHYDRATES
Life’s Sweet
Molecules

2.
-They act as storehouses of chemical energy (glucose, starch, glycogen); are the
components of supportive structures in plants (cellulose), crustacean shells
(chitin) and connective tissues in animals (acidic polysaccharides) and are
essential components of nucleic acids (D-ribose and 2-deoxy-D-ribose).
-Carbohydrates make up about three fourths of the dry weight of plants. But in
animals it is less than 1%.
- General molecular formula - CnH2nOn
- Several non-carbohydrates compound are (acetic acid C2H4O2 and lactic acid
C3H6O3) also appear as hydrates of carbon. But, some of genuine
carbohydrates (rhamnohexose C6H12O5 and deoxyribose C5H10O4) do not
satisfy the general formula.

3.
- Animals get their carbohydrates by
eating plants but they do not store much,
than they consume.
-Carbohydrates are produced by
photosynthesis in plants, such as glucose
are synthesized in plants from CO2, H2O,
and energy from the sun. Then, are
oxidized in living cells to produce CO2,
H2O, and energy.

4.
Each year, 100 metric tons of CO2 is converted to Carbohydrates by plants

5.
Carbohydrates
Disaccharides
2 sugar units
Oligosaccharides
3-10 units
Polysaccharides
>10
e.g.Glucose,
fructose etc
e.g.Sucrose e.g. Maltotriose
Homoglycans
e.g. starch,
glycogen
Heteroglycans
e.g. GAGs or
glycosaminoglycans

6.
Carbohydrates that cannot be hydrolysed into simpler carbohydrates are
called as monosaccharides.
Structure and Nomenclature
The general formula CnH2nOn
With one of the carbons being the carbonyl group of eitheran aldehyde or a
ketone.
The most common monosaccharides have three to eight carbon atoms.
The suffix-ose indicates that a molecule is a carbohydrate, and the prefixes tri,
tetr-, pent-, and so forth indicate the number of carbon atoms in the chain
like, triose, tetrose, pentose, etc.
Monosaccharide containing an aldehyde group are classified as aldoses; those
containing a ketone group are classified as ketoses.
1.
Sucrose (C12H22O11) + H2O acid or certain enzyme Glucose (C6H12O6) + Fructose (C6H12O6)
MonosaccharidesDisaccharides

7.
Monosaccharide further classified on the basis of functional group and number
of carbon atoms present in their structure
3 Trioses
Aldotriose e.g. glyceraldehyde Ketotriose e.g. Dihydroxyacetone
4 Tetroses
Aldotetrose e.g.
Erythrose
Ketotetrose e.g.
Erythrulose
5 Pentoses
Aldopentoses e.g
Arabinose, Xylose, Ribose
Ketopentosese.g.
Xylulose, Ribulose
6 Hexoses
Aldohexose e.g. Glucose,
Galactose, Mannose Ketohexose e.g. Fructose
7 Heptoses
Aldoheptose: Glucoheptose Ketoheptose e.g Sedoheptulose
No. of
carbon
atom
Generic
name
ALDOSE KETOSE
On the basis of functional groupOn the basis of no. of carbon atom

8.
Structural aspects of monosaccharides
Stereoisomerism
Compounds having same structural formula, but differing in spatial configuration
as known as stereoisomers.
Asymmetric carbon/ Chiral carbon: Four different groups are attached to the
same carbon.
The number of asymmetric carbon atoms (n) determines the possible isomers of
a given compound which is equal to 2n e.g. glucose contains 4 asymmetric carbons
thus having 16 isomers.
The reference molecule is glyceraldehyde.
All monosaccharides can be considered as molecules derived from glyceraldehyde
by successive addition of carbon atoms.

9.
D- and L- isomers
D and L Isomers are mirror images of each other.
The spatial orientation of H & OH groups on the C- atom (C5 for glucose), adjacent to
the terminal primary alcohol carbon determines whether the sugar is D or L Isomer.
If the OH group is on the right side, the sugar is of D- Isomer. If the OH group is on the
Left side, the sugar is of L- Isomer. Mammalian tissues have D- sugars.
Penultimate
carbon
Penultimate
carbon

10.
Optical activity/ Optical Isomerism
Optical activity is a characteristic feature of compounds with asymmetric
carbon atom. Carbon atom can have four different groups then the carbon
atom will possess asymmetry. A carbon atom is said to be asymmetric when
its mirror images are non-super imposable on each other.

11.
Theses types of compounds are called enantiomeric pair. Enantiomers
Have identical physical properties but they interact differently with
polarized light.
When a beam of polarized light is passes through a solution of an optical
isomer, it will be rotated either to the right or left. Depending on the rotation,
molecules are called dextrorotatory (+) or levorotatory (-). The optical
rotation is measured by an instrument called polarimeter.
[α]λ
T = α/ l x C
[α]λ
T = specific rotation at temp. T with wavelength λ
α = observed rotation
L = length of sample tube
C= concentation in gm/ml

12.
Racemic mixture:
If D & L isomers are present in equal concentration, it is
known as racemic mixture.
NOTE: Racemic mixture does not exhibit any optical activity, since the dextro
and levorotatory activities cancel each other.
Specific rotation of some sugars

13.
Epimers
If two monosaccharides differ from each other in their configuration
around a single specific carbon atom, they are referred as epimers to each
other.
Glucose & galactose are C4-epimers.
Glucose & mannose are C2-epimers
Inter-conversion of epimers is known as epimerization, epimerase
catalyzes this reaction.

14.
Anomerism – Mutarotation
Anomers have same composition but differ in the orientation of groups around
anomeric carbon atom.
Anomeric carbon is a hemiacetal or carbonyl carbon atom, e.g. 1st carbon atom in
glucose is anomeric carbon atom.
Carbonyl carbon atom becomes asymmetric because of ring structures of
monosaccharides in solution thus anomers are encountered in cyclic structures of
monosaccaharides.
The alpha & beta cyclic forms of D-glucose are known as Anomers.
They differ from each other in the configuration only around C1 known as
anomeric carbon.
In case of alpha anomer, the OH group held by anomeric carbon is on the opposite
side of the group CH2OH of sugar ring

15.
Anomers are expressed as α and β forms.
In α form “OH” group is below the plane (OH group is oriented away from the
oxygen atom)
In β form “OH” group is above the plane (OH group is oriented towards the
oxygen atom)
Mutarotation:
When D-glucose is crystallized at room temperature and a fresh solution is
prepared, its specific rotation of polarized light is 112o; but after 12- 18 hrs it
changes to +52.5 o
Mutarotation is defined as the change in the specific optical rotation
representing the interconversion of α and β forms of D-glucose to an
equilibrium mixture.

16.
Glucose and Fructose has two anomers α and β

17.
Cyclization
• Less then 1% of CHO exist in an open chain form.
• Predominantly found in ring form.
• involving reaction of C-5 OH group with the C-1 aldehyde group or C-2 of keto group.
• Six membered ring structures are called Pyranoses .
• Five membered ring structures are called Furanoses .
Straight chain form

18.
PROPERTIES OF MONOSACCHARIDES
1. Physical properties:
Monosaccharides are colourless, crystalline compounds, readily soluble in
water and sweet in taste. Their solutions are optically active and exhibit
mutarotation.
2. Chemical properties:
a) Reduction: When treated with reducing agents such as sodium
amalgam, hydrogen can reduce sugars. Aldose yields corresponding
alcohol. Ketoses form two alcohols because of appearance of new
asymmetric carbon in this process.
D-Glucose D-Sorbitol
D-Fructose D-Sorbitol+D-Mannitol

19.
b) Oxidation: upon oxidation aldose sugars like glucose yields carboxylic acid,
the aldehyde group is oxidized to carboxyl group to produce respective acids.
Glucose  Gluconic acid
Mannose  Mannonic acid
Galactose  Galactonicacid

20.
c) Formation of esters: Hydroxyl groups of sugars can be esterified to form
acetates, propionates, benzoates, etc. Sugar phosphates are of great biological
importance. Metabolism of sugars inside the body starts with phosphorylation.
e.g Glucose 6-P04
d) Formation of osazone: this test is given by reducing sugar like, glucose,
fructose, lactose and maltose. In this test phenyl hydrazine is reduced to phenyl
hydrazone by sugar solution. Phenyl hydrazone when heated with more amount
of phenyl hydrazine forms yellow crystals of osazone.

21.
e) Furfural formation/Dehydration: Monosaccharides when treated with
concentrated H2SO4 undergoes dehydration with the removal of 3 molecules of
water. Hexoses give hydroxymethyl furfural and pentoses give furfural. Furfurals
condense with phenolic compounds to give various colors.
E.g. Molisch’s test: General test for carbohydrates (H2SO4 and α-naphthol). Rapid
Furfural and Seliwanoff’s test: Tests for presence of keto group

22.
Some important Monosaccharides

23.
2.
When two monosaccharides (similar or dissimilar) are combined together by
glycosidic linkage, a disaccharide is formed.
All are isomers with molecularformula C12H22O11
On hydrolysis they yield 2 monosaccharide which soluble in water
Even though they are soluble in water, they are too large to pass through the cell
membrane.
There are two types
Non-reducing
Sucrose
Trehalose
Cane sugar
in yeast
Reducing
Lactose
Maltose
Milk sugar
Malt sugar

24.
Condensation and Hydrolysis—Forming and Breaking Glycosidic
Bonds
• The –OH group that is most reactive in a monosaccharide is the one on the
anomeric carbon.
• When this hydroxyl group reacts with another hydroxyl group on another
monosaccharide a glycosidic bond is formed.
• During this reaction, a molecule of water is eliminated as two molecules join.

25.
• Condensation reaction is a type of reaction that occurs when two molecules
are joined and a water molecule is produced. This type of reaction is referred
to as a dehydration reaction. Condensation reactions occur between
different types of functional groups that contain an –H in a polar bond, like
O–H or N–H, and an –OH group that can be removed to form water.
• Hydrolysis reaction is the reverse of a condensation reaction. A larger
moleculeforms two smaller molecules and water is consumed as a reactant.

26.
• In the case of maltose, the glycosidic bond is specified as α(1→4) and is simply stated
as alpha-one-four.
• If the –OH group had been in the beta configuration when the glycosidic bond was
formed, the bond would be in the β(1→4) configuration. The molecule formed would
be named cellobiose and would have a different two-dimensional and three-
dimensional shape than maltose.
Maltose

27.
Sucrose (glucose+ fructose)
• Sucrose is known as table sugar.
• It is the most abundant disaccharide found in nature.
• Sucrose is found in sugar cane and sugar beets.
• The glycosidic bond is α β (1→ 2).
• Both anomeric carbons of the monosaccharides in sucrose are bonded,
therefore, sucrose is non-reducing sugar. It will not react with Benedict’s
reagent. Also it not form osazone crystals in osazone test.
• When hydrolyzed, it forms a mixture of glucose and fructose
• Clinical Importance:-
-dental caries
-Bypasses metabolic
check points- OBESITY
-Sucrase deficiency

28.
Inversion of Sucrose
• Hydrolysis of sucrose (optical rotation +66.5o) will produce one molecule
of glucose (+52.5o) and one molecule of fructose (-92o)
• Therefore the products will change the dextrorotation to levorotation
(INVERSION)
• Equimolecular mixture of glucose and fructose thus formed is called as
Invert Sugar
• The enzyme producing hydrolysis of sucrose is called INVERTASE

29.
Maltose (glucose+ glucose)
• Maltose is known as malt sugar.
• 2 glucose residues α (1 → 4) linkage
• Another form is α (1 → 6) called as Isomaltose.
• It is formed by the breakdown of starch. Malted barley, a key ingredient in beer,
contains high levels of maltose.
• During germination of barley seeds, the starch goes through hydrolysis to form
maltose. This process is halted by drying and roasting barley seeds prior to their
germination.
• One of the anomeric carbons is free, so maltose is a reducing sugar.
Osazone test:- Star shaped or flower petal shaped

30.
Lactose (galactose+ glucose)
• Lactose is known as milk sugar.
• It is found in milk and milk products.
• The glycosidic bond is (1→4).
• An intolerance to lactose can occur in people who inherit or lose the ability to
produce the enzyme lactase that hydrolyzes lactose into its monosaccharide units.
• One of the anomeric carbons is free, so lactose is a reducing sugar.
• Osazone test – Powder Puff or hedgehog shaped

31.
Homoglycan Or
Homopolysaccharide
Heteroglycan Or
Heteropolysaccharide
3. Polysaccharides
Polysaccharides are large molecules containing 10 or more monosaccharide units.
Carbohydrate units are connected in one continuous chain or the chain can be
branched.
1. Storage polysaccharides contain only α- glucose units. Three important
ones are starch, glycogen, and amylopectin.
2. Structural polysaccharides contain only β- glucose units. Two important
ones are cellulose and chitin. Chitin contains a modified β- glucose unit

32.
Homopolysaccharides (all one type of monomer), e.g., glycogen,
starch, cellulose, chitin, inulin, dextran.
Heteropolysaccharides (different types of monomers), e.g.,
peptidoglycans, glycosaminoglycans
Branched polysaccharides
Unbranched/ Linear polysaccharides

33.
Starch
Carbohydrates of the plant kingdom
Sources: Potatoes, tapioca, cereals (rice, wheat) and other food grains
Starch is a homopolymer composed of D-glucose units held by α-glycosidic
bonds.
Composed of two polysaccharide components-Amylose & Amylopectin
Amylose:
• Amylose makes up 20% of plant starch and is made up of 250–4000 D
glucose units bonded α (1→4) in a continuous chain.
• Long chains of amylose tend to coil.
• Mol wt =400,000 or more
• It is water soluble
α -amylose
HOMOPOLYSACCHARIDES

34.
Amylopectin:
• The insoluble part absorbs water and forms paste like
gel;
• Amylopectin makes up 80% of plant starch and made up of glucose units,
but is highly branched with molecular weight more than 1 million.
• The branching points are made by α- 1, 6 linkage

35.
Hydrolysis of Starch
• About every 25 glucose units of amylopectin, a branch of glucose units are
connected to the glucose by an α(1→6) glycosidic bond.
• During fruit ripening, starch undergoes hydrolysis of the α(1→4)
bonds to produce glucose and maltose, which are sweet.
• When we consume starch, our digestive system (α-amylase)breaks it down
into glucose units for use by our bodies.
• Starch will form a blue coloured complex with iodine; this color disappears on
heating and reappears when cooled. This is a sensitive test for starch.
• When starch is hydrolyzed by mild acid, smaller and smaller fragments
are produced.
• The hydrolysis for a short time produces amylodextrin (violet color with
iodine and non-reducing).
• Further hydrolysis…………….amylodexerythrodexarchrodextrin Maltose

36.
Glycogen
• Storage form of energy in animal. Stored in liver and muscle
• Stores more glucose residues per gram than starch.
• More branched and compact than starch.
• A homopolysaccharide (number of glucose units upto 25000): linear chain of
α (1→4) linked glucosyl residues with branches joined by α (1→6) linkages
• More energy in a smaller space.
• Glycogen in liver (6-8%) is higher than that in the muscles (1-2%).
• Liver glycogen - first line of defense against declining blood glucose levels
especially between meals.

37.
Cellulose
• Glucose units combined by β-1,4 linkages.
• Straight line chain with no branches. This allows chains to align next to each
other to form a strong rigid structure.
• Mol wt 2-5 million.
• Cellulose is an insoluble fiber in our diet because we lack the enzyme
cellulase to hydrolyze the β-1,4 glycosidic bond. Whole grains are a
good source of cellulose. Cellulose is important in our diet because it
assists with digestive movement in the small and large intestine.
Some animals and insects can digest cellulose because they contain
bacteria that produce cellulase.
• Commercial applications: nitrocellulose, cellulose acetate membranes
for electrophoresis.

38.
Chitin
• Chitin makes up the exoskeleton of insects and crustaceans and cell walls of
some fungi.
• It is made up of N-acetyl glucosamine containing β(1→4) glycosidic bonds.
• It is structurally strong.
• Chitin is used as surgical thread that biodegrades as a wound heals.
• It serves as a protective Exoskeleton in crustacea and insects.
• Chitin is also used to waterproof paper, and in cosmetics and lotions to retain
moisture.

39.
Dextrins/Dextrans
• Highly branched homoglycan containing Glucose residues in 1-6, 1-4 and
1-3 linkages.
• Produced by microbes.
• Mol. wt:- 1-4 million.
• As large sized, they will not move out of vascular compartment so used as
plasma expanders.
Inulin
• D -fructose in β-1,2 linkages.
• Source: Bulbs and tubers chicory, dahlia, dandelion, onions, garlic.
• Not metabolized .
• Not absorbed nor secreted by kidneys so, used to measure GFR.

40.
HETEROPOLYSACCHARIDES
Polymers made from more than one kind of monosaccharides or monosaccharide
derivatives. e.g., mucopolysaccharides, Agar & Agarose and glycoproteins.
MUCOPOLYSACCHARIDES
First isolated from mucin so called mucopolysaccharides
• Long, Unbranched heteropolysaccharide, made of repeating disaccharide
units containing uronic acid & amino sugars. These are more commonly
known as Glycosaminoglycans (GAG).
• Amino sugar – Glucosamine or Galactosamine (Present in there acetylated
form)
• Uronic acid – D-Glucuronic acid
• Major components of extracellular matrix of connective tissue, including bone
and cartilage, synovial fluid, vitreous humor and secretions of mucus
producing cells.

41.
Hyaluronic acid
It is the simplest mucopolysaccharide and is a linear polymer of disaccharides
which form the repeating unit.
Each disaccharide is linked to the next by β- 1,4 glycosidic bonds. It consists of
two alternative units of D-glucuronic acid and N-acetyl D-glucosamine, linked
by β-1,3 to give a thread like structure.
Present in Synovial fluid of joints, vitreous humor, connective tissues and cartilage.
Sulfate free
Sulfate containing
Hyaluronic acid
Chondroitin Sulphate, Dermatan sulphate, keratan sulphate,
Heparin, Heparan Sulphate

42.
Functions:
• Serves as a lubricant and shock absorbant in joints.
• Acts as seives in extracellular matrix.
• Permits cell migration during morphogenesis & wound repair.
• Hyaluronidase is an enzyme that breaks β1 – 4 linkages of hyaluronic acid.
• Present in high concentration in seminal fluid, & in certain snake and insect
venoms. Hyaluronidase enzyme of semen degrades the gel around ovum & allows
effective penetration of sperm into ovum, thus helps in fertilization.
Condroitin sulphates
Widely distributed in bone, cartilage, skin, heart & tendons. The repeating unit is a
disaccharide and consisting of alternate units of D-glucuronic acid linked to sulphate
ester of N- acetyl galactosamine.
Functions:
• In cartilage, it binds collagen & hold fibers in a tight strong network.
• Role in Compressibility of cartilages in weight bearing.

43.
Heparin
Heparin is a medically important polysaccharide because it prevents clotting in the
bloodstream.
It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized
monosaccharide and D-glucosamine. Heparin also contains sulfate groups that are
negatively charged.
present intracellular: In granules of mast cells and also in lung, liver and skin.
Functions:
• It is an anticoagulant (prevents blood clotting)
• Heparin helps in the release of the enzyme lipoprotein lipase (LPL) which helps to clear
the lipidemia after fatty meal – so called clearing factor.

44.
AGAR
Contains galactose, glucose & other sugars. Obtained from sea weeds
Functions:
• Cannot be digested by bacteria. So used as supporting agent to culture bacterial
colonies.
• Also as support medium of immuno diffusion & immuno-electrophoresis.
AGAROSE
Galactose and 3,6 anhydrous galactose units. Used as matrix for electrophoresis.
GLYCOPROTEINS
• Several proteins are covalently bound to carbohydrates which are referred to as
glycoproteins. The carbohydrate content of glycoproteins varies from 1% to 90% by
weight. The term mucoprotein is used for glycoproteins with carbohydrate
concentration more than 4%. Glycoproteins are very widely distributed in the cells and
perform variety of functions like enzymes, hormones, transport proteins, structural
proteins, blood group antigens and receptors.
• The carbohydrates found in glycoproteins include mannose, galactose, N-acetyl
glucosamine, N-acetyl galactosamine, xylose and N-acetylneuraminic acid (NANA)

45.
Qualitative tests for Carbohydrates
To study the properties of carbohydrates
To identity of an unknown carbohydrate by carrying out a series of chemical
reactions
1. SOLUBILITY (to differentiate mono and disaccharides from
polysaccharides)
Mono and disaccharides are soluble in water to give clear solution.
Whereas, polysaccharides are insoluble in water.
2. MOLISCH TEST (for all carbohydrates)
Principle: Carbohydrates when treated with concentrated
sulphuric acid undergo dehydration to give furfural
derivatives. These compounds condense with Alpha
naphthol to form colored products. Pentoses yield furfural
while Hexoses yield 5-Hydroxy methyl furfurals.

46.
This is a sensitive but a non- specific test and is given positive by all types of
carbohydrates. If the oligosaccharides or polysaccharides are present they
are first hydrolysed to monosaccharides which are then dehydrated to give
the test positive.
3. BENEDICT’S TEST (to differentiate reducing sugars from non-
reducing sugars)
-Carbohydrates with free aldehyde or ketone groups have the ability to
reduce solutions of various metallic ions.
-Reducing sugars under alkaline conditions tautomerise and form
enediols.
-Enediols are powerful reducing agents.
-They reduce cupric ions to cuprous form and are themselves
converted to sugar acids.
-The cuprous ions combine with OH- ions to form yellow
cuprous hydroxide which upon heating is converted to red
cuprous oxide.

47.
4. FEHLING’S and TOMMER’S TEST (to differentiate reducing sugars
from non-reducing sugars)
Reducing sugar reduces copper ions present in the Fehling solution so as to
give red precipitate
5. BARFOED’S TEST (to differentiate monosaccharides from
disaccharides )
Aldoses and ketoses can reduce cupric ions even in acidic
conditions. This test is used to distinguish reducing
monosaccharides from disaccharides by controlling pH and
time of heating. Mono saccharides react very fast whereas
disaccharides react very slowly. The positive reaction indicates
the presence of a reducing mono saccharide. On prolonged
heating disaccharides can also give this test positive. Hence,
the solution should be boiled for 3 minutes only.

48.
6. SELIWANOFF’S and RAPID FURFURAL TEST
(to differentiate ketoses from aldoses)
Keto hexoses on treatment with hydrochloric acid form
5-hydroxy methyl furfural which on condensation with
resorcinol gives a cherry red colored complex.
7. HYDROLYSIS OR INVERSION TEST (to confirm sucrose)
Sucrose is a non-reducing sugar, since it does not have free
aldehyde or ketone group to cause reduction, hence it gives
a negative reaction with Benedict’s reagent. But upon boiling
with HCl, sucrose is hydrolyzed to yield glucose and fructose,
which give positive reactions with benedict and Seliwanoff
reagents.

49.
8. OSAZONE TEST (to differentiate among reducing sugars by their
crystalline structure)
A solution of reducing sugar when heated with phenyl hydrazine,
Characteristic yellow crystalline compounds called Osazone are
formed. These crystals have definite crystalline structure,
precipitation time and melting point for different reducing sugars.
Needle shaped
glucosazone crystals
as viewed under the
microscope
Galactosazone
crystals as viewed
under the
microscope(Rhom
bic plates)
Sun flower
shaped
Maltosazone Powder puff/hedge hog
shaped Lactosazone

50.
9. IODINE TEST (for all polysaccharides)
Iodine forms a coordinate complex between the helically coiled
polysaccharide chain and iodine centrally located within the helix
due to adsorption. The color obtained depends upon the length of
the unbranched or linear chain available for complex formation
Left to right: Lugol's iodine, starch solution, starch solution with iodine.

51.
Diseases related to Carbohydrates metabolism
1) Diabetes mellitus (D.M.)
• When the body is unable to utilize the glucose then there is an appearance of
excessive sugar in the blood, as well as in the urine called glycosuria and the
disease is termed as diabetes mellitus.
• It is a group of metabolic disorders with a common characteristic feature of
hyperglycemia.
• The blood sugar level is regulated by the pancreatic protein hormone insulin,
which is secreted by the β- cells of islets of langerhans of pancreas.
• Hyperglycemia in D.M. Is due to defect in insulin action, secretion or both.
Diabetes mellitus is broadly classified into 2 categories:
a) Type 1 diabetes: it is characterised by absolute deficiency of insulin due to
destruction of β- cells of pancreas.
b) Type 2 diabetes: it is caused due to peripheral resistance to insulin action
and inadequate secretion of insulin by β- cells of pancreas.

52.
The blood glucose level rises remarkably (>200 mg/dl) than normal (70-120
mg/dl) in D.M.
Characteristics or Symptoms:
hyperglycemia (increased in blood sugar),
glycosuria (sugar in urine),
increased fat and protein metabolism,
ketosis (increased in ketone bodies in tissue),
hypercholesterolemia (blood LDL increased),
atherosclerosis (plaque formation on the wall of artery),
polyuria (increased urine volume),
polydipsia (increased thirst),
polyphagia (excessive ingestion of food),
coma and death.
Treatment: D.M., can be treated by administering insulin subcutaneously or
by giving oral antidiabetic/ oral hypoglycemic agents. Patient may advised to
take protein diet but not the carbohydrate diet.

53.
2) Glycosuria
Appearance of usually high amounts of sugar in the urine is called as glycosuria.
Depending upon the causes, glycosuria has been classified into various groups
as:
a) Alimentary glycosuria: this term is used to denote glysouria which sets up
after the consumtion of excessive amounts of sweet things like glucose, cane
sugar, sweets or even starch via diet.
b) Diabetic glycosuria: it is pathological condition in which carbohydrate
metabolism gets impaired which results into appearance of sugar in the
urine.
c) Renal glycosuria (Renal diabetes): this occurs due to some defect in the
renal tubular transport mechanism of glucose.
d) Adrenaline glycosuria: it is also known as emotional or psychic glycosuria.
It occurs generally due to hypersecretion of adrenaline hormone from adrenal
cortex.
Glycosuria can be detected in urine by benedicts or barfoed’s tests.

54.
3) Galactosemia
Due to deficiency of the enzyme galactose 1- phosphate uridyl transferase and
galactokinase, galactose can not be converted into glucose, which leads to a
condition called as galactosemia. It is characterized by increased galactose levels
in blood and urine. Accumulated galactose is converted into galactitol, which is
responsible for development of cataract. The clinical symptoms of galactosemia
are jaundice, hepatospleenomegaly, mental retardation, etc.
4) Fructose intolerance
One of the very normal hexose sugar of fruits (i.e. Fructose) gets normally
metabolised to give energy and CO2, but defective metabolism of fructose
develop in high concentration of this sugar in blood, disorder known as fructose
intolerance.

55.
5) Glycogen storage diseases:
The metabolic abnormalities related with glycogen synthesis and degradation
are collectively termed as glycogen storage diseases. These are:
a) Van glerke’s disease: it is due to hepatic glycogen storage.
b) Pompe’s disease: it is due to storage of normal glycogen in almost every
organ of the body, including the heart.
c) Limit dextinosis; forbe’s or cori’s disease: it is due to increased
deposition of glycogen with very outer branches in the liver and other
tissues.
d) Amylopectonosis or anderson’s disease: it is due to deficiency of
branching enzymes which results in accumulation of glycogen.

56.
Functions/ Role of Carbohydrates
• Serve as main sources of ENERGY in body (4kcal/g)
1) As structural component: Carbohydrates are the essential components of
some structural materials of living organisms:
- Monosaccharides act as a constituents of nucleic acids, coenzymes,
flavoproteins and blood group substances.
- Immuno-polysaccharides play an important role in the resistance of
infections.
- Hyaluronic acid is a viscous substance in the matrix of connective tissue and
various other tissues, acts as a good lubricant.
- Heparin, is a naturally occuring anticoagulant, prevents blood coagulation.
- glucoronic acid, acts as detoxifying agent by forming complex with toxic
substances.
- Glycosides are the components of steroid hormones, act as cardiotonic
agent.

57.
2) Supply and storage of energy:
-carbohydrates, supplies and stores energy. About 60% of energy is supplied by
the catabolism of carbohydrates. 1 gm of carbohydrates on oxidation gives 4
calories of energy. Glucose is the sole form of energy for the brain and nervous
tissues.
- stored glycogen, in the liver, also provides energy in absence of glucose.
3) Regulates fat metabolism: carbohydrates are required for the normal
oxidation of fats. In the absence of carbohydrates, fat deposition occurs in the
body and may give risk to ketosis.
4) Carbohydrates provides essential energy to the body by sparing protein for
building of tissues.
5) It also plays a role in gastrointestinal functions. Polysaccharides like cellulose,
pectin give bulk and help in the peristaltic movements of the digestive tract.

58.
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