9 biomolecules
DESCRIPTION
Visit http://students-learn.blogspot.com for more materials.TRANSCRIPT
BIOMOLECULES-CLASS XI BIOLOGYBIOMOLECULES-CLASS XI BIOLOGY 11
BIOMOLECULESBIOMOLECULES
PREPARED BYS RATH PGT BIO K V III BBSR
http://students-learn.blogspot.com/
BIOMOLECULES-CLASS XI BIOLOGY 2
Biomolecules of cells All carbon compounds that are found in
the living tissues are called Biomolecules. Example-carbohydrate, fat, protein, amino
acids, lipids etc.
BIOMOLECULES-CLASS XI BIOLOGY 3
Classification of Biomolecules
BIOMOLECULES
MICROMOLECULESMol. Wt.< 1000
MACROMOLECULESMol. Wt. >1000
Amino acid nucleotidesSugars , lipids
Polysaccharides, proteinsNucleic acids
BIOMOLECULES-CLASS XI BIOLOGY 4
Amino acids
These are organic compounds which contain an amino group and an acidic group .
They are substituted methane with 4 substituent groups occupying the 4 valency positions of the carbon; these are hydrogen, carboxyl group, amino group & a variable group designated as R group.
BIOMOLECULES-CLASS XI BIOLOGY 5
Amino acids
There are 20 amino acids occur in protein. A specific characteristic property of amino
acids is the ionizable nature of amino and carboxyl group, so the structure of amino acids changes in solutions of different pHs.
BIOMOLECULES-CLASS XI BIOLOGY 6
Types of amino acids
Basic – lysine arginine Acidic – glutamic acid aspartic acid Neutral – alanine glycine valine Aromatic – phenyl alanine , tyrosine,
tryptophan
BIOMOLECULES-CLASS XI BIOLOGY 7
Sugars
Simplest sugars are monosaccharides, which cannot be hydrolysed further composed of 3-7 carbon atoms. E.g. glyceraldehydes, ribose, glucose, fructose etc.
They have either free aldehyde or ketone group which reduce cupric ion to cuprous ion ,called reducing sugar.
BIOMOLECULES-CLASS XI BIOLOGY 8
Sugars
Oligosaccharides may have two or a few monosaccharides.
Bond between two monosaccharides is called glycosidic bond.
BIOMOLECULES-CLASS XI BIOLOGY 9
lipidslipids
Straight chaincompound
Fused hydrocarbonRing e.g. cholesterol
simple compound
oil phospholipids
fats
waxes
glycolipids
sphingolipids
BIOMOLECULES-CLASS XI BIOLOGY 10
Nucleotides Organic compounds with heterocyclic rings. A nucleotide consists of a nitrogenous base, a
pentose sugar and a phosphate group. A nucleoside has a nitrogenous base attached to
a pentose sugar. The nitrogenous bases are called adenine,
guanine, thymine, cytosine and uracil Polymerised nucleotides form DNA and RNA
which are the genetic material.
BIOMOLECULES-CLASS XI BIOLOGY 11
Primary and secondary metabolites
Metabolites may be primary or secondary type. Primary metabolites have identifiable functions
and play specific roles in the normal physiological processes. E.g. amino acids, nitrogenous bases, nucleic acids etc.
Secondary metabolites are products of certain metabolic pathways. E.g. pigments, rubber, gums, resins, carotenoids etc.
BIOMOLECULES-CLASS XI BIOLOGY 12
Polysaccharides These are a class of organic compounds
(carbohydrates) which are long chain polymers of monosaccharides.
They are of two types: homopolysaccharides, heteropolysaccharides
Homopolysaccharides- cellulose, starch, inulin Heteropolysaccharides- chitin
BIOMOLECULES-CLASS XI BIOLOGY 13
Proteins They are heteropolymers containing a string or
strings of amino acids. A peptide bond formed between the carboxyl
group and the amino group of successive amino acids, joins the amino acids together.
Proteins result from the 20 amino acids , depending on the no.of amino acids and sequence of amino acids.
There are 4 levels of protein structure.
BIOMOLECULES-CLASS XI BIOLOGY 14
Primary structure of protein
Protein exists as a long chain of amino acids arranged in a particular sequence.
It is nonfunctional. Position of amino acid in a protein is obtain
from this. 1st a. a is called N-terminal and last is called C-
terminal a. a.
BIOMOLECULES-CLASS XI BIOLOGY 15
Secondary structure of protein
There is interaction between every fourth a. a by formation of hydrogen bond. The polypeptide has a helical shape. E.g. keratin.
Only right handed helix are formed. If two or more chains are held together by
intermolecular hydrogen bonds, the structure is called pleated sheet. E.g. silk fibres.
BIOMOLECULES-CLASS XI BIOLOGY 16
Tertiary structure of protein
When a polypeptide chain becomes further stabilised by folding and coiling by the formation of ionic or hydrophobic bonds or disulphide bridges, the protein is said to be tertiary structure.
E.g. amylase, pepsin and other enzymes.
BIOMOLECULES-CLASS XI BIOLOGY 17
Quaternary structure of protein
When a protein has many sub units, each having primary, sec. And tertiary st. of its own, the protein is said to be quaternary.
E.g. haemoglobin, insulin
BIOMOLECULES-CLASS XI BIOLOGY 18
Enzymes They are proteins that catalyse biochemical
reaction, so called biocatalysts. Specific for their substrate. Each enzyme require a specific (optimum) pH &
temp. Accelerate a reaction by reducing the activation
energy.
BIOMOLECULES-CLASS XI BIOLOGY 19
Nomenclature of enzyme Named by adding the suffix ‘ase’ to the
substrate. E.g. sucrase According to the physiological activity it
catalyses. E.g. oxidase, dehydrogenase The source from which they are obtained.
E.g.papain from papaya.
BIOMOLECULES-CLASS XI BIOLOGY 20
Classification of enzyme Oxidoreductase Transferase Hydrolases Lyases Isomerasees ligases
BIOMOLECULES-CLASS XI BIOLOGY 21
Mechanism of enzyme action
Three dimensional structure of enzyme has one or more active site where the substrate binds.
Active site acts as ‘ lock’ into which substrate fits in like a ‘key’.
The point where substrate binds is called ‘substrate binding site’.
Substrate binding causes lowering of activation energy & reaction to proceed at a faster rate.
Binding of substrate induces the enzyme to alter its shape and fit more tightly.
Breaking of chemical bond of substrate and formation of E-P complex.
Enzyme releases product and free enzyme take up another molecule.
BIOMOLECULES-CLASS XI BIOLOGY 22Activation energy requirement
BIOMOLECULES-CLASS XI BIOLOGY 23
Factors affecting enzyme action Temperature pH Substrate concentration chemicals
BIOMOLECULES-CLASS XI BIOLOGY 24Effect of substrate concentration
velocity
(s)
Vmax