Biomolecules

have free aldehydic or ketonic

BIOMOLECULES non-reducing sugars. They do not
Chemical substances which form the basis of living systems are group. e.g. sucrose.
called biomolecules. Classification based on functional group of carbohydrates:
are
nucleic acids, vitamins, i) Carbohydrates
Aldose which contain aldehydic group
eg Carbohydrates, proteins, etc. :

called aldose. e.g. glucose.

CARBOHYDRATES (ii) Ketose : which contain ketonic group are
Carboh ydrates
called ketose. e.g. fructose.
Carbohydrates optically active polyhydroxy aldehydes
are or
Classification of carbohydrates based on number of carbon
ketones or the compounds which produce these molecules on
atoms present in a monosaccharide molecule :
hydrolysis. e.g. glucose, sucrose, starch, etc.
Classification of carbohydrates on the basis of hydrolytic (i) Triose It has three carbon atoms.
(ii) Tetrose : It has four carbon atoms.
products carbon atoms.
that cannot be entose: It has fivecarbon
Monosaccharides: A carbohydrate (iv) Hexose I t has six atoms.
hydrolysed to simpler polyhydroxy aldehydes or ketones is (v) Heptose I t has seven carbon atoms.

called monosaccharide e.g. glucose, fructose, ribose, etc.

e.g. (i) Ribose is aldopentose i.e. it has aldehydic group and
About 20 monosaccharides are known to occur in nature. five carbon atoms.
Gi) Oligosaceharides : A carbohydrate that yields two toten ii) Glucose is aldohexose i.e. it has aldehydic group and six
monosaccharide units on hydrolysis is called oligosaccharide. carbon atoms.
These are further classified as disaccharides, trisaccharides, Monosaccharides
tetrasaccharides --, -- - , , decasaccharides. 1. Glucose : Glucose occurs in nature in free as well as
Disaccharides Carbohydrates which provide twocombined form. It is present in sweet fruits, honey etc.
disaccharides. (i) Preparation: Glucose is obtained when sucrose is boiled
nOnosaccharides on hydrolysis are called
e.g. Sucrose, lactose, maltose. with dilute HCI in alcoholic solution.
Polysaccharides : Carboh ydrates which yield a large CHO, + H,0> C,H.O, +C,H.O.
Der of monosaccharide units on hydrolysis are called Sucrose Glucose Fuctose

polysaccharides. Pure glucose is obtained by the hydrolysis ofstarch or cellulose

g Starch, cellulose, glycogen, gum, er at 393 K under pressure in presence of H,O.
the basis of taste:
Cation of carbohydrates on in taste are called [CH.0, +nH,0> nC,H,O,
gars: Carbohydrates which are sweet Starch or Cellulose Glucose
gars. e.g. fructose, sucrose, etc. (ii) Structure of glucose
y Non-sugars C a r b o hy d r a t e s w h i c h a r e n o t s w e c t u a (a) From clemental analysis and molecular weight

Care ca dnon-sugars. e.g. polysaccharides.

determination, molecular formula of glucose was found to be
55ifieation of carbohydrates based on reducingpropeyCH,,0
which reduce
ucing sugars : AII those carbohydrates
Fehli S
(b) Glucose when heated with red P and HI gives n-hexane.
Solution and Tollens' reagent are known as redueng

All the monosaccharides [containing aldehydes

and
CH,O, Red P-l CH,-CH,-CH,- CH,- CH,-CH,
Keton8 -llexane
Ones both] are reducing sugars. do not indicates presence ol traight chain of six carbon atoms in
On-reducing sugars: All the carbohydrates which
reduce Tollens' reagen
ent and Fehling's
solution are called glucose.
(c) Glucose reacts with hydroxylamine to form an oxime and Objections to open chain structure of glucose
adds a molecule of hydrogen cyanide to give Glucose does not give 2, 4 DNP test, Schiff's
Glucose + H,N-
cyanohydrin. .
and t test a
OH Oxime does not form hydrogen sulphite addition product
Glucose +HCN
wi
Cyanohydrin NaHSO
These reactions indicate presence
of carbonyl group in glucose. The pentaacetate of glucose does not react
with
(d) Glucose on reaction with mild oxidising agents like bromine hydroxylamine which indicates the absence of free-CHO
water, Tollens' reagent, etc. gives gluconic acid containing six
carbon atoms. group.
This reaction indicates that glucose contains Glucose exists in two different erystalline forms named as
aldehydie group. aand B. These are called anomers.
CH,O, CHO NatC,H,O, - COOH
Crystallisation of
concentrated solution at 303 K gives ol-glucose
(e) Glucose
ofglucose (m.p
reacts with acetic anhydride to give pentaacetate. 419 K). Crystallisation of hot saturated aqueous solution at
It means glucose contains five -OH groups. 371 K gives B-glucose (m.p. 423 K).
Glucose is stable compound it means five-OH Open chain structure of glucose fails to explain these
groups are
attached to five different carbon atoms. reactions. Therefore, a cyclic hemiacetal structure
CHO CHO O was proposed. Glucose forms a sixX-membered ring in which
ofglucose
-CHO group combines with - OH group at C - 5.
(CHOH), (CHCO (CHO-CCH,) Cyelie structure of glucose

CH,OH
CH-0 -CH H C OH
CH.OH
Glucose pentaacetate H
(f) Glucose and gluconic acid both on oxidation with nitric H-C-OH
acid give saccharic acid [Hexane H
dicarboxylic acid]. This O
OH H
reaction indicates presence of a
primary alcohol at carbon HO-C-H
number six. HO OH
Keeping in mind all the above mentioned facts and tetravalency H OH
of carbon, structure of glucose may be H-( OH
a-D-Glucose
proposed as given.
CHO
H C Haworth projection formula
CHOH
CHOH H-C OH

CHOH H
HOH C-D-Glucose
This structure
CH,OH explains all the above
properties of glucose
Glucose which arise due to absence of -CHO group.
Fischer after studying many other properties, proposed following
configuration for glucose. D (+) - glucose where 'D' represents Fructose
the contiguration "(+) represents dextrorotatory nature of the ) Structure
molecule. (a) Elemental analysis and molecular
H. molecular formula of fructose as
weight caleulation suggest
(b) Fructose undergoes nucleophilicCH,,0.
C=0

and
addition ofhydroxylamine
hydrogen cyanide but does not reduce Tollens' reagent and
H-C-OH cannot be oxidised
by bromine water. It indicates the presenee
of a ketonic group.
HO-C (c) Fructose when heated with red
P and HI gives norma
hexane indicating the
presence of straight chain of six caroo
H-C-OH atoms.
(d) On oxidation with strong
oxidising agents it gives carboxye
H OH acid having only five carbon atoms. This indicates the
of ketonic group at carbon number 2. Fructose is a
prese
H - C-OH
compound. -OH group
at carbon number
laevorotato
is on the right si
Hence, it belongs to D-series.
H Fructose also exists in two mbered

Fischer projection formula of glucose cyclic forms having five nc

ring.
 CH,OH
-OH
H
HOH o H

OH - 0-

CH,OH -OH OH HO CHOH

H OH
OH H
-H HO O
a-D (+)-Glucose B-D Fructose
- l of
-OH H= -OH Sucrose is non-reducing sugar. Thus -OH group of C
a
formation with
glucose is involved in glycosidic linkage
OH H -OH group of C 2 of fructose.
rotation of
Inversion of sugar The change in the sign of
sucrose from dextro(+) to laevo(-) in solution
is called inversion
OH H-Ç-OH of sugar and the product is named as invert sugar.
Reason: Sucrose is dextrorotatory but after hydrolysis it gives
H
and fructose. Since the
laevorotatory
dextrorotatory glucose
a-D(--Fructofuranose laevorotation of fructose (-92.4°) is more than dextrorotation
of glucose (+52.5°). Therefore, the mixture is laevorotatory.

2. Maltose : Maltose is a reducing sugar. On hydrolysis it

gives only o-D-glucose. In maltose C 1 of one glucose is -

linked to C - 4 of other glucose by glycosidic linkage.

HO- CH,OH
CHOH CH,OH
H
HO-C-H H
H OH
H
OH
H-C-OH -0-
HO OH
OH H OH
H
H-C a-D-Glucose
a-D-Glucose
3. Lactose: Lactose on hydrolysis gives equimolar mixture
H- -OH of B-D-glucose and B-D-galactose. In lactose C- 1 of galactose
is linked with C - 4 of glucose by glycosidic linkage. It is more
H
commonly known as milk sugar. Since, it is found in milk.
B-D-)-Fructofuranose
CH,OH CHOH
OH H
-0 OH
O
H
HOH.C CH.OH HOH,C O OH OH O- OH
H

H H H
" H HO/OH HO/CH,OH H OH H OH

B-D-Galactose B-D-Glucose
OH H OH H
C, of glucose is free hence it is a reducing sugar.
-D-)-Fructofuranose B-D--Fructofuranose
Polysaccharides
Disaccharides Carbohydrates which upon hydrolysis give a large number of
monosaccharide units are caled polysaccharides. It acts as the
arbohydrates which give two monosaccharide units on
food storage or structural materials.
rolysis with dilute acids or enzymes are called disaccharides.
O monosaccharides may be same or different. The bond 1. Stareh: It is the main storage polysaccharide of plants. It
is called is the most important dietary source for human beings.
Ch binds two monosaccharides together
glycosidic linkage. It is a mixture of two components:
. Sucrose
Sucrose on hydrolysis with enzyme invertase (a) Amylose: It is water soluble. It constitutes about 15-20%
of starch. It is straight chain polymer of a-D(+)glucose units
and
cquimolar
B-D fructose.
mixture of a-D(+)-glucose held by C, - C, glycosidic linkage. It contains nearly

200-1000 units.
 CHOH CH.OH I t is major portion in our food.
H H
-O It acts as storage molecules as starch in
H plants and glycogen
H in animals.
OH
Cell wall of bacteria and plants is made up of cellulose.
H OH H OH Wood is a form of cellulose used in furnitures.
CH.OH Cotton fibre is made of cellulose used for clothes.
H H H Wines are made by fermentation of carbohydrates.
H Nucleic acids contain D-ribose and 2-deoxy-D-ribose
-0 OHH
H
o- OH
carbohydrates.
(b) Amylopectin: It is water insoluble. It constitutes 80-85%
of starch. It is branched chain polymer
POINTSTOBE NOTED
of o-D-glucose. A chain Disaccharides may contain same or different
is formed by C, C glycosidic linkage whereas chains are
-

joined to each other by C, - C, glycosidic linkage. monosaccharide units.

Polysaccharides are not sweet in taste, hence they are
CH.OH CHOH called non-sugars.
H H H H
-o K H
OH H All monosaccharides whether aldose or ketose are
OH H reducing sugar.
Sucrose is non - reducing whereas maltose and lactose
H OH H OH are reducing.

CHOH CH, Glucose is most abundant organic compound on Earth.

H H The letters D and L before the name ofa
compound
-o- OH L 4KOH indicate only relative configuration of a particular isomer.
It is not related to direction of rotation of
plane polarised
OH H OH light.
HOHC Glucose is dextrorotatory (+) whereas fructose is

N. laevorotatory ().
-0 HO4 Glucose has pyranose structure whereas fructose has
furanose structure.
HO H The oxide linkage which joins two monosaccharide units
2. Cellulose : It is most abun organic substance in plant together is called glycosidic linkage.
kingdom. It is main constituent of cell walls of plant cells. It On hydrolysis, sign of rotation of sucrose
is straight chain polymer of
B-D-glucose joined by changes from
dextro (+) to laevo (-). This is called inversion of
C,-C glycosidic linkage. sugar.
Starch is storage polysaccharide
CHOH of plants and glycogen
is storage carbohydrate of animals whereas
H cellulose is
the structural material of cell wall of
plant cells.
OH
H CHOH H PROTEINS5
H OH
H The word protein is derived from Greek word "Proteios" which
OH H means primary or of prime importance. Proteins are the most
H
abundant biomolecules of the
H OH living system. Main sources of
roteins are milk, cheese,
3. Glycogen : It is stored carbohydrate present in animal| pulses, peanuts, fish, meat, etc. Proteins
body. It is also known as 'animal starch because its Structure
are responsible for structure and functions of life.
These are
is similar to amylopectin and is rather more highly branched required for growth and maintenance of body.
polymer of a-D-glucose. It is present in liver, muscles and Amino Acids
brain. It is also found in yeast and fungi. Glycogen breaks by | Organic compounds containing both amino (-NH,) and carboxy
the action of enzymes to glucose on demand of the body. -COOH) functional groups are called amino acids.
Importance of Carbohydrates R-CH-COOH
. Carbohydrates are essential for life for both plants and
animals. NH,
O- Amino acid
a-Aminoacid:4Amino cids in which -NH, group is present Structure of Proteins
called O-amino acids. linked by amide
C,
on
are
Proteins are the polymers of d-amino acids
Nomenclature : All Calica
acids have their typical names.
| fornmation between carboxyland amino group. This S

However, amino acids are presented by a three letter or one

peptide bond or peptide linkage.
letter symbol.

Glycine Gly G
OH
Alanine Ala A H,N-CH-C - OH +H,N-CH-C
Valine Val or V H,o R
Classification of Amino Acids R

Based on nature of compound

(a) Acidic amino acids : Amino acids which contain more
carboxyl groups than the amino groups in the molecule are
- HN-CHCHN-

amide
CH-
-1
called acidic amino acids e.g. Glutamic acid, Aspartic acid. R
(b) Basic amino acids: Amino acids which contain more Peptide bond or linkage

amino groups than the carboxyl groups are called basic amino These amides are called dipeptide,tripeptide depending
acids. on number of amino acids combining together. When number
e.g. Arginine, Lysine. of amino acids combining together is more than ten then it is
well defined
(e) Neutral amino acids : called polypeptide. Polypeptides
Amino acids which contain equal having a

number of amino and carboxyl groups are called neutral amino conformation are called proteins.
acids e.g. Glycine, Valine. contain polypeptides having more than
Generally, proteins
hundred amino acids having molecular mass more than
Based on source
have very less number
(a) Essential amino acids: Amino acids which cannot be
T0,000u but there are proteins which
o amino aCids.
synthesized in the body and must be obtained through diet are
e.8. Insulin, it contains only 51 amino acids.
Known as essential amino acids e.g. Valine, Leucine, Isoleucine.

(D) Non-essential amino acids : Amino acids which can beProteins

have four layered structure:

synthesized in the body are called non-essential amino acids. Primary structure
e.g. Glycine, Alanine, Aspartic acid. Secondary structure
Tertiary structure
Properties of Amino Acids Quaternary structure
Amino acids are colourless, crystalline solids. (a) Primary structure: The sequence of amino acid present
These are water soluble. in polypeptide chain is called primary structure.
These are high melting solids. e.g. Val, Ala, Gly, Ala, Val, Gly
Amino acids exist as zwitter ion in aqueous solution.
It is held by peptide (amide) linkage.
(b) Secondary structure : Arrangement of polypeptide chains
HN-CH-COOH H,N- CH CO0
is called secondary structure.
There are two types of secondary structures:
R R
(Zwitter ion) (i) a-helix structure: In this structure
Neutral
(Amphoteric)
polypeptide chains are
coiled like a helix in which two adjacent turns are held
together
HN-CH-COOH H,N-CH-COO by forming hydrogen bond between C=0 ofone turn and NH
of next turn.
R R
Acidic
Basic
ionic form amino acids show amphoteric
Witter
behaviour.
acids except glycine are optically actiVe,
amino
asymmetric. *L° forms,
no acids are also classified as D' and
have
naturally occurring amino
acids L
configuration. anode (+) in basic medium and
toward.us migrate towards There is a constant pH
medium.
at hthode (-) in acidic of the
h amino acids will not migrate towards any
Odes. This is called 'isoelectric point.
 (i) B-pleated sheet structure: In this structure polypeptide ENZYMES
chains run paraliel to each other. These chains are held together
Enzymes are a type of proteins. Almost all the enzymes
by forming H-bond between C=O and NH of adjacent chain. are
globular proteins. Enzymes are biocatalyst. They catalyse
chemical reactions taking place in living organisms.
Enzymes
are named after the
compound or class of compound or the
reaction upon which they work. e,g.
HYDROGEN
BOND i) Maltase catalyses hydrolysis of maltose into glucose.
(i) Invertase catalyses inversion of cane sugar.
(iii) Oxidoreductase catalyse the oxidation of one substrate
with simultaneous reduction of another substrate.
N iv) Urease catalyses hydrolysis of urea.
Characteristics
(c) Tertiary structure : Arrangement of secondary structure Enzymes are highly specific for a particular reaction and
is called tertiary structure. for a particular substrate.
It is of two types: Enzymes are highly selective.
(G) Fibrous proteins: In this structure polypeptide chains are Very small amount of enzyme is required for the progress
arranged parallel to each other forming a rod like structure. of a reaction.
(ii) Globular proteins : In this structure polypeptide chains Enzyme enhances the rate of reaction by providing alternate
are randomly arranged and coiled forming globules. In both the path of lower activation energy.
structures polypeptide chains are held together by forming e.g. Activation energy for acid hydrolysis of sugar (sucrose)
intermolecular H-bond, disulphide linkage, van der Waal bond. is 6.22 kJ/mol, while the activation
energy for enzyme.
(d) Quaternary structure: Conformation of tertiary structure sucrose is only 2.15 kJ/mol.
in three dimensional space is called quaternary structure.
Native The natural form of
protein POINTS TO BE NOTED
protein with proper
arrangement is called native protein. Almost all the enzymes are globular proteins and are
Denaturation : The process due to which protein loses its specific for a particular reaction and substrate.
biological activity due to physical change (temperature) or
chemical change (pH) is called denaturation.
Enzymes catalyse a reaction by reducing the magnitude
of activation energy.
In denaturation secondary and tertiary structure of protein is
destroyed whereas primary structure of protein remains intact. VITAMINS
e.g. Boiling of egg, curdling of milk etc.
The term vitamin is made of two words 'vital' and
'amine.
Because earlier identified vitamins are amine derivatives but
POINTS TO BE NOTED nowadays most of the vitamins do not contain amino
A l l proteins are made of a-amino acids. group.
Therefore, these days it is termed as 'vitamin'.
O-amino acids exist as dipolar ions known as zwitter Organic compounds required in the diet in small amounts
ionic form. to perform specific
biological functions for normal
Amide group formed between a amino acids is called maintenance of optimum growth and health of the
organism
peptide bond or peptide linkage. are called vitamins.
I n primary structurea -amino acids are linked
bycovalent Def+ciency of vitamins causes specit+c diseases.
bond. In secondary structure these chains are joined by Classification of Vitamins
hydrogen bonds while in tertiary structure the main forces
Vitamins classified on the basis of solubility.
are
are hydrogen bonds, disulphide linkages, van der Waals
i) Water soluble vitamins Vitamins which are soluble in
force and electrostatic force of attraction.
water. e.g. Vitamins B and C.
During denaturation 2° and 3° structures of proteins are (ii) Fat soluble vitamins : Vitamins which are soluble in fat
destroyed but 1° structure remains intact and protein and oils but insoluble in water.
loses its biological activity. e.g. Vitamins A, D, E and K.
These are stored in liver and adipose tissues. Excess of vitamins Structure of Nucleic Acids
er e also harmful. Hence, vitamin pills should not be taken () Primary structure : The sequence of nucleotides in the
advice of doctor. polynucleotide chain of a nucleic acid is called its primary
without the
structure.
(ii) Secondary structure : Arrangement of polynucleotide
POINTS TO BE NOTED
chain is called secondary structure.
Most of the vitamins cannot be synthesised by our body J a m e s Watson and Francis Crick gave a double stranded
but plants can synthesise almost all of them. helix structure for DNA.
The two nucleic acid chains are wound about each other.
NUCLEIC ACIDS
The two chains are held by hydrogen bonds
together
Long chain polymers of nucleotides responsible for heredity between specific base pairs.
transmission and protein synthesis are called nucleic acids. bonds with thymine where
Adenine forms two hydrogen
There are mainly two types of nucleic acids as cytosine forms three hydrogen bonds with guanine.
(i) RNA (ii) DNA (A = T, G= C)
Both of the nucleic acids are made of a pentose sugar, phosphoric The two strands are complementary to each other.

acid and nitrogen containing heterocyclic bases. Structure of RNA

In primary structure of RNA the pentose sugar is ribose and
Composition of Nucleic Acids four bases are adenine, guanine, cytosine and uracil.
DNA contains 2-deoxyribose sugar, phosphate group. four bases stranded helix in
Secondary structure of RNA has single
(adenine, cytosine, guanine and thymine). which hydrogen bond is formed between adenine, guanine,
A unit formed by attachment of a base at one position ofa sugar cytosine and uracil. RNA' molecules are of three types

is called nucleoside. (i) -RNA (Transfer RNA)

Nucleoside = Base + Sugar. (ii) r-RNA (Ribosomal RNAA)
(ii) m-RNA (Messenger RNA)
A unit formed by attachment of a base to one position of
sugar and phosphoric acid at five position is called Functions of Nucleic Acids
nucleotide. DNA is reserve of genetic in formation and responsible for
Nucleotide = Base + Sugar+ Phosphate heredity transmission.
O DNA is exclusively responsible for maintaining the identity
of different species.
0=P-0 DNA is capable of self duplication during cell division.
O Therefore, identical DNA strands are transferred to daughter
cells.
The most important function of nucleic acid is protein
HOH,C Base CH 0 Base synthesis. Proteins are synthesized by RNA molecules in
the cell but the message for the synthesis of a particular

H protein is present in DNA.

H H H
H

OH OH OH OH POINTS To BE NOTED
Nucleoside Nucleotide The in the nucleus of the cell, responsible for
particles
Nucleotides are joined together by phosphodiester linkage heredity are called chromosomes which are made up of
between C, and C, atoms of the pentose sugar. proteins and nucleie acids.
Sugar Base DNA contains thymine but RNA contains uracil in
addition to three common bases adenine, guaninc and

cytosine.
Phosphate Nucleotides are joined together by phosphodiester linkage
between 5 and 3 carbon atoms of pentose sugar.
Sugar Base Two strands of DNA are held togethher by hydrogen
bonds formed between specific base pairs. Adenine forms
two hydrogen bonds with thymine and guanine forms
Phosphate three hydrogen bonds with cytosine.

Sequence of bases on DNA is unique for

person. It is
a

Sugar Base same for every cell and cannot be altered by any treatment.
 HORMONES In females, these include estrogens wnich stimulate
development of female sex characteristics during puberty,
Hormones chemical substances that produced in minute
are are

by
quantitiesThe specialised organs called ductless endocrine
some or Peptide Hormones
glands. hormones produced by these glands move to the Oxytocin and Vasopressin are the two examples.
different
parts of the
body through blood stream. Hormones play
an important role in regulating metabolic processes and sex Insulin
characteristics. Hormone deficiency leads to abnormal metabolic
It regulates the metabolism of glucose. Its deficiency causes
processes. Chemically, the hormones belong to different classes
of compounds. diabetes
Steroid Hormones Amine Hormones
Some important steroids include sex hormones. In males, these These are either amines or amino acids. Two important examples
include androgens, testosterone. These hormones, stimulate the are adrenaline or epinephrine (secreted by the medulla ofthe
development of male sex characteristics during puberty. adernal cortex) and thyroxine (secreted by the thyroid gland)

Sammay
Carbohydrates are optically active polyhydroxyaldehydes Proteins in which polypeptide chains run parallel and are
or ketones or molecules which provide such molecules on held together by hydrogen and disulphide bonds are called
hydrolysis. fibrous proteins.
Carbohydrates are classified into monosaccharides Proteins in which polypeptide chains coil around to give
disaccharides and polysaccharides depending on thenumber a spherical shapt are called globular proteins.
of molecules produced on hydrolysis. The specific sequence of a-amino acids present in
Carbohydrates are also classified as reducing and non- polypeptide chains are called primary structure.
reducing aldose and ketoseetc. Polypeptide chains exist either in a-helix or in
Glucose exists as o and B-D+) glucopyranose and fructose B-pleated sheet structure. This is called secondary
exists as a and B-D-fuctofuranose. structure.
Linkage between two monosaccharide units through oxygen Folding of secondary structure gives either fibrous or
atom is called glycosidic linkage. globular shape. This is called tertiary structure.
In sucrose C I of a-D(+) ghucose is linked with As a result of change in temperature or pH the hydrogen
bonds of proteins are disturbed. Globules unfold and
C-2 of B-D() fructose by glycosidic linkage. It is non-
helix get uncoiled and protein loses its biological activity
reducing sugar. GThis is called denaturation of protein.
I n maltose o-D(+) glucose units are held by C 1 and
Enzymes are biological catalysts. Enzymes are hignuy
C-4 a glycosidic linkage. specific and selective.
I n lactose C 1 of B-D-galactose and C 4 of
B-D-glucose are held by B-glycosidic 1inkage. Organic compounds required in the diet in small amouns
to
Starch is storage polysaccharide of plants whereas perform specific biological functions for normal
maintenance of optimum growth and health of organism
glycogen is the main storage carbohydrate of animals. are called vitamins.
Starch is a mixture ofamylose (15-20%) and amylopectin Vitamins are water soluble (B and C) and at solubie
(80 85%). (A, D, E and K). Deficiency of vitamins causes many disea
Cellulose is a polymer of p-D-glucose which are joined Chemical substances responsible for transmission
byC 1 and C - 4 glycosidic linkage.
heredity characters are known as nucleic acids. Therea
Ten amino acids can be synthesised in the body which are mainly two types of nucleic acids (i) RNA and (i) DN
and
known as non-essential amino acids whereas ten amino There are three types of RNA (i) mRNA, (i) RNAan
acids cannot be synthesised in the body and must be (ii) tRNA.
obtained through diet are known as essential amino acids. the
Nucleic acid is responsible for protein synthesis l
O-Amino acids are dipolar in nature known as zwitter cell.
1ons. DNA consists of deoxyribose
a d e n i n e

Proteins are polymers of o-amino acids joined together by

sugar, phospnaicts of
thymine, guanine and cytosine whereas RNA consi
cytosine.
peptide (amide) linkage ribose sugar, phosphate,
adenine, uracil, guanine ana e