biomolecules

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.