SHAHINA AKHTERXI A
GULF ASIAN ENGLISH SCHOOL
BIOMOLECULES
1. ANALYSIS OF CHEMICAL COMPOSITION OF LIVING ORGANISMS
• Take a living tissue, weigh & grind it in trichloroacidic acid
• Thick slurry is filtered through cheese cloth
Filtrate
Retentate
• Inorganic compounds – ‘ash analysis’• Living tissue is weighed to get wet
weight• This is dried dry weight• C CO2 + H2O• Ca, Mg, Na, K
2.BIOMOLECULES OF CELLS
CHEMISTRY
BIOLOGICAL
MICROMOLECULES
MACROMOLECULES
M < 1000 MICROMOLECULES
(i)Amino acids(ii)Sugars(iii)Nucleotides(iv)Lipids
M > 1000 BIOMACROMOLECULES
(i)Polysaccharides(ii)Nucleic acids(iii)Proteins
• Acid-soluble fraction cytoplasmic composition
• Acid-insoluble fraction macromolecules of cytoplasm + cell organelles
COMPONENTS
%
(i) Water(ii) Proteins(iii)Nucleic acids(iv)Carbohydrates(v) Lipids(vi)Ions
70 – 9010 – 155 – 7About 3About 2About 1
3. AMINO ACIDS
(i)Basic amino acidsLysine
(ii)Acidic amino acids Glutamic acid
(iii)Neutral amino acidsAlanine
Aromatic amino acids
Phenyl alanine
4.SUGARS
• Monosaccharides : simplest sugars, which cannot be hydrolysed further into smaller sugars
• Composed of 3-7 C atoms :(i) Triose (3C) (Glyceraldehyde)(ii) Tetrose (4C) (Erythrose)(iii) Pentose (5C) (Ribose)(iv) Hexose (6C) (Glucose)(v) Heptose (7C) (Sedoheptulose)
Glucose
Galactose
• Monosaccharides have either a free CHO / CO group reducing sugars• Oligosaccharides : when 2/ few
monosaccharides are combined by glycosidic bonds• They are named as:(i) Disaccharides (2) : Sucrose(ii) Trisaccharides (3) : Arabinose(iii) Tetrasaccharides (4) :Stachyose(iv) Pentasaccharides (5) : Verbascose
Maltose
5.LIPIDS
• Heterogenous group of organic compunds
• Water insoluble but soluble in non-polar organic solvents
Lipids
Straight chain compounds
Fused hydrocarbon rings+ long hydrocarbon chain e.g, cholesterol
Simple lipids
Oil Fats Waxes Phospholipids Glycolipids Sphingolipids
Compound lipids
CHOLESTEROL
• Lipids fatty acid COOH – R ( -CH3 , -C2H5 , -CH2)
PALM
ITIC
ACID
Fatty acids
Saturated fatty acids – butyric acid
Unsaturated fatty acids – linoleic acid
Simple lipid – glycerol
Formed by esterification of glycerol with fatty acids – monoglycerides , diglycerides , triglycerides
Fats – high m.p & remain soilds at room temp (Butter)
Oils – low m.p & remain liquids at low room temp (Sunflower oil)
• Phospholipids – when lipids have P & phosphorylated organic compounds e.g. lecithin
• Brains have sphingolipids
PHOSPHOLIPID - LECITHIN
6.NUCLEOTIDES
Phosphorylated nucleosides – adenylic acid, guanylic acid, thymidylic acid, cytidylic acid & uridylic acid
N base attached to pentose sugar – adenosine, guanosine, thymidine, cytidine & uridine
• Purine + pyridimine monomers
• Higher nucleotides store energy in their high energy P bonds
• Nicotinamide + riboflavin coenzymes
• Coenzymes : non – protein organic moiety of holoenzyme
7.PRIMARY & SECONDARY METABOLITES
PRIMARY SECONDARY
IDENTIFIABLE FUNCTIONS
PRDTS OF CERTAIN METABOLIC PATHWAYS
• PRIMARY METABOLITES – amino acids, N bases, proteins, nucleic acids, etc.
• SECONDARY METABOLITES(i) Pigments :
Anthocyanin, carotenoids(ii) Drugs : Vinblastin,
curcumin(iii) Alkaloids : Morphine,
codeine(iv) Essential oils : Lemon
grass oil(v) Lectins :
Concanavalin A(vi) Terpenoids :
Monoterpenes(vii) Toxins : Abrin, Ricin(viii) Polymeric Compounds : Rubber,
cellulose, gums
8.BIOMACROMOLECULES
• M > 1000 daltons• Found in acid – insoluble fraction
POLYSACCHARIDES NUCLEIC ACIDS PROTEINS LIPIDS
9. POLYSACCHARIDES
HOMOPOLYSACCHARIDES(CELLULOSE , STARCH)
HETEROPOLYSACCHARIDES(CHITIN)
MONOMER GLUCOSE
PRESENT IN PLANT CELL WALL
Starch Glycogen Inulin
GLUCOSE GLUCOSE FRUCTOSE
PLANTS ANIMALS
STORAGE POLYSACCHARIDE
STORAGE POLYSACCHARIDE
Amylose
Amylopectin
10.NUCLEIC ACIDS
DNA RNA
RIBONUCLEIC ACID (RNA)
mRNA : Carries information from DNA to ribosome
Decides sequence of amino acids
tRNA: Carries an amino acid from cytoplasm to r ibosome
rRNA: Forms parts of ribosomes Forms part of seat of protein
synthesis
11.PROTEINS
• Heteropolymers containing string/strings of amino acids• Types of proteins result from
20 amino acids • Depending on• (i) no. of amino acid residues• (ii)sequence of amino acids
STRUCTURE OF PROTEINS
(i) Primary structure
(ii) SECONDARY STRUCTURE
(iii) TERTIARY STRUCTURE
(iv) QUARTERNARY STRUCTURE
CLASSIFICATIONPROTEINS
FIBROUSPolypeptides arranged in parallel bundles (silk fibres, keratin & collagen)
GLOBULARPolypeptides become coiled & folded (albumin, globulin, haemoglobin )
PROTEINS
SIMPLEComposed of amino acids(histones, albumins)
CONJUGATEPeptide chain & cofactor
CONJUGATE PROTEINS
• Chromoproteins – pigments along with amino acids (haemoglobin)
• Lipoproteins – lipids in their molecules (egg yolk)• Phosphoproteins – phosphate grp with amino
acids (casein of milk)• Metalloproteins – contain metallic ion with amino
acids (Zn carbonic anhydrase)• Glycoproteins – contain carbohydrates with
amino acids• Nucleoproteins – contain nucleic acids with
amino acids (virus)
PROTEINS FUNCTIONS
1. Collagen Intercellular/extracellular ground
substance
2. Trypsin Enzyme to digest protein
3. Insulin A hormone that regulates glucose level
4.Gamma globulin Antibody, that fights against infections
5.Receptors Proteins that receive stimulus/substance
6.GLUT- T Regulates transport of glucose into cells
12.CONCEPT OF METABOLISM
METABOLIC PATHWAYS – DYNAMIC STATE OF BODY CONSTITUENTS
LINEAR CIRCULAR
METABOLISM
ANABOLISMMore complex compounds are formed from simple ones (proteins synthesis)
CATABOLISMComplex substance is broken into 2 / more smaller substances (Digestion of proteins by peptides
13. ENZYMESCHARACTERISTICS OF ENZYMES
• Proteins that catalyse biochemical reactions in living cells
• Each enzyme catalyses the reaction of 1 substrate
• Each enzyme requires a specific pH & temp
• They accelerate a reaction
SIMILARITIES BETWEEN ENZYMES & INORGANIC CATALYSTS
• Catalysts remain unchanged at the end of the reaction & they can be used again
• Required in far less quantities as compared to the substrate
• Do not initiate a reaction, but rate of reaction by lowering activation energy
• Do not alter eqm of a reversible reaction
• Form short-lived complexes with substrates
DIFFERENCES B/W ENZYMES & INORGANIC CATALYSTS
ENZYMES INORGANIC CATALYSTS
All enzymes are proteins & have complex molecular organisation
Usually small & simple molecules
An enzyme catalyses only a specific reaction
They can catalyse a no. of reactions, hence are not specific for any 1 reaction
Enzyme action can be regulated by specific molecules
Cannot be regulated by any other molecule
These are more sensitive to changes in pH & temp of medium
They are v.less affected by changes in pH & temp of medium
NOMENCLATURE OF ENZYMES
• Adding suffix ‘ase’ to the substrate on which they act e.g.,sucrase , protease etc.
• Acc. To physiological activity it catalyses e.g.,oxidase , dehydrogenases, decarboxylase etc.
• Acc. To source from which they are obtained e.g., papain, bromelain etc.
• Some have been named like ptyalin, trypsin etc .
CLASSIFICATION OF ENZYMES
• CLASS 1 : OXIDOREDUCTASES
• Catalyse oxidation /reduction of a substance
• Cytochrome oxidase oxidises cytochromes• Glycolate oxidase oxidises glycolate
Sreduced + S’oxidised Soxidised + S’reduced
CLASS 2 : TRANSFERASES
• They catalyse transfer of specific groups from 1 substrate to another
• Glutamate pyruvate transaminase
• S – G + S’ S + S’- G
CLASS 3 : HYDROLASES
• Catalyse breakdown of larger molecules into smaller molecules with addition of H2O
Amylase hydrolases starch
CLASS 4 : LYASES
• Catalyse cleavage of specific covalent bonds & removal of specific groups , without the use of H2O
Histidine decarboxylase cleaves histidine into histamine & CO2
X Y
C – C X – Y + C = C
CLASS 5 : ISOMERASES
• Catalyse rearrangement of atoms in a molecule to form isomers
• Phosphohexose isomerase converts glucose 6-phosphate into fructose -6-phosphate
CLASS 6 : LIGASES
• Catalyse covalent bonding b/w 2 substrates to form a large molecule, mostly involving utilisation of energy by hydrolysis of ATP
RuBP carboxylase catalyses the joining of RuBP & CO2 in photosynthetic C fixation
MECHANISM OF ENZYME ACTION (LOCK & KEY HYPOTHESIS)
CATALYTIC CYCLE :
(i) Substrate binds to active site of enzyme(ii)Binding of substrate induces the enzyme to
alter its shape & fit more tightly around substrate
(iii)Active site of enzyme, now in close proximity of substrate breaks the chemical bonds of substrate & an enzyme-product complex is formed
(iv)Enzyme releases the product of reaction & the free enzyme is ready to take up another molecule of substrate
FACTORS AFFECTING ENZYME ACTION
• Temperature
• Effect of pH
• Effect of substrate concentration
• Effects of chemicals When binding of a chemical reduces /
shuts off the enzyme activity, the chemical is called inhibitor. INHIBITORS
COMPETITIVEWhen inhibitor closely resembles substrate in molecular structure & binds to active site of enzyme
NON-COMPETITIVE When inhibitor does not compete with substrate for active site
• Feed back inhibition: Enzyme activity is inhibited by prdt of same enzyme reaction
GLUCOSE-6-PHOSPHATE
INHIBITS ACTION OF HEXOKINASE
CATALYSES
PHOSPHORYLATION OF GLUCOSE
• Co-factorsENZYMES
SIMPLE ENZYMES CONJUGATE ENZYMES
Made of 1/several polypeptide Has non-protein moiety + polypeptide chain
COFACTOR
PROSTHETIC GROUP COENZYME METAL IONS
TIGHTLY BOUND TO APOENZYME
BOUND TO APOENZYME DURING COURSE OF CATALYSIS
METAL IONS FORM CO-ORDINATION BONDS WITH SIDE CHAIN AT ACTIVE SITE OF ENZYME & SUBSTRATE
HAEM NAD & NADP Zn
I would like to express my special thanks of gratitude to my teacher Mrs. Alarmelu Natchiar as well as our principal Mrs Nasreen Banu who gave me the golden opportunity to do this wonderful presentation on the topic BIOMOLECULES, which also helped me in doing a lot of Research and i came to know about so many new thingsI am really thankful to them.Secondly I would also like to thank my parents and friends who helped me a lot in finishing this presentation within the limited time.
I am making this presentation not only for marks but to also increase my knowledge .THANKS AGAIN TO ALL WHO HELPED ME.