Biomolecules

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Biomolecules

  1. 1. Biomolecules dr.aarif
  2. 2. Chemicals or molecules present in the living organisms are knownas BiomoleculesThe sum total of different types of biomolecules, compounds and ions present in a cell is called as cellular poolBiomolecules are compounds of carbon.Hence the chemistry of living organisms is organized around carbonCarbon is the most versatile and the most predominant element of life. ELEMENT Non living Living Matter (Earth crust) Hydrogen 0.14 0.5 Carbon 0.03 18.5 Oxygen 46.6 65.0 Nitrogen Very less 3.3 Sulphur 0.03 0.3 Sodium 2.8 0.2 Calcium 3.6 1.5 Magnesium 2.1 0.1 dr.aarif Silicon 27.7 Very less
  3. 3. BIOMOLECULESInorganic OrganicMinerals CarbohydratesGases LipidsWater Amino acids Proteins Enzymes Nucleotides Nucleic acids Vitamins dr.aarif
  4. 4. BIOMOLECULES Micro molecules MacromoleculesSmall sized, low mol wt Large sized, high mol wtBetween 18 and 800 daltons Above 10000 daltonsFound in the acid soluble pool Found in the acid insoluble pool Minerals Carbohydrates Gases Lipids Water Proteins Sugars Nucleic acids Amino acids nucleotides dr.aarif
  5. 5. The major complex biomolecules of cellsBiomolecule Building block Major functionsProtein Amino acid Basic structure and function of cellDNA Deoxyribonucleotide Hereditary informationRNA Ribonucleotide Protein synthesisPolysaccharide Monosaccharide Storage form of energyLipids Fatty acids & glycerol Storage form of energy to meet long term demands dr.aarif
  6. 6. NUCLEOTIDES dr.aarif
  7. 7. SUGARN2 BASES dr.aarif
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  9. 9. DNA dr.aarif dr.aarif
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  12. 12. m- RNA r- RNA t- RNA dr.aarif
  13. 13. Carbohydrates dr.aarif
  14. 14. CARBOHYDRATESCarbohydrates are the most abundant organic molecules in nature.The term carbohydrate is derived from the French termhydrate de carbone i.e. it is a hydrate of carbon or Cn(H2O)nCarbohydrates are defined as organic substances having C, H & OWherein H and O are in the ratio 2:1 as found in H2O FUNCTIONS OF CARBOHYDRATES - Most abundant source of energy (4 cal/g) - Precursors for many organic compounds (fats, amino acids) - Present as glycoproteins and glycolipids in the cell memebrane and functions such as cell growth and fertilization - Present as structural components like cellulose in plants, exoskeleton of some insects, cell wall of microorganisms - Storage form of energy (glycogen) to meet the energy demands of the body. dr.aarif
  15. 15. CARBOHYDRATESMONOSACCHARIDES OLIGOSACCHARIDES POLYSACCHARIDESBasic units of carbohydrates Non crystalline, non soluble They can be furtherCannot be hydrolysed into in water, tasteless, on hydrolysedsmaller units hydrolysis gives mol of monosaccharidesa. Based on the no. of a. Disaccharides e.g. starch , cellulose C-atoms b. Trisachharidesa. Based on the type of c. Tetrasachharides functional group dr.aarif
  16. 16. MONOSACCHARIDESBased on the no of C-atoms Based on the functional group - Trioses (C3H6O3) - Aldoses : the functional group is e.g. Glyceraldehyde, Aldehyde –CHO Dihydroxyacetone e.g. Glyceraldehyde, glucose - Tetroses (C4H8O4) e.g. Erythrose, Threose - Pentoses (C5H10O5) e.g. Ribulose, Xylose Arabinose (deoxyribose – C5H10O4) - Hexoses (C6H12O6) - Ketoses : the functional e.g. glucose, fructose group is ketone galactose, mannose ( C = O) - Heptoses (C7H14O7) e.g. Dihydroxyacetone, e.g. sedoheptulose fructose glucoheptose dr.aarif
  17. 17. Derivatives of Monosaccharides1. Deoxy Sugars : Deoxygenation of ribose produces deoxyribose, which is a structural component of DNA2. Amino Sugars : When 1 or more –OH groups of monosaccharides are replaced by –NH2 (amino group) it forms an amino sugar e.g. Glucosamine, which forms chitin, fungal cellulose, hyaluronic acid.3. Sugar Acid : Oxidation of –CHO or –OH group forms sugar acids. Ascorbic acid is a sugar acid4. Sugar alcohols : Reduction of aldoses or ketoses. Glycerol and Mannitol. dr.aarif
  18. 18. OLIGOSACCHARIDESThey are formed by condensation of 2-9 monosaccharidesDepending upon the no. of monosachharide molecules they are :a. Disaccharides (sucrose, lactose)b. Trisaccharides (raffinose)c. Tetrasaccharides (stachyose)The smallest and the commonest oligosaccharides are Disaccharides dr.aarif
  19. 19. DISACCHARIDESA disaccharide consists of 2 monosaccharide units (similar or dissimilar)held together by a glycosidic bondThey are crysatalline, water soluble and sweet to taste.MALTOSE : - is also called as malt sugar. - made up of 2 glucose moleculesLACTOSE : - is also called as milk sugar as it is found naturally in milk - made up of glucose and galactose - souring of milk is due to conversion of lactose to lactic acidSUCROSE : -is also called as cane sugar. It is the sugar found in sugar cane and sugar beet - most abundant among naturally occuring sugars. - Important source of Dietary carbohydrates - made up of glucose and fructose dr.aarif
  20. 20. POLYSACCHARIDES- Also called as GLYCANS- Made up of repeating units of monsaccharides held by glycosidic bonds- During its formation a water molecule is released at each condensation This helps reduce the bulk making it almost insoluble decreasing its effect on the water potential or osmotic potential ofthe cell- Unlike sugars they are not sweet.- They are ideal as STORAGE AND AS STRUCTURAL COMPONENTS- They are of 2 types Homoglycans and Heteroglycans. HOMOGLYCANS HETEROGLYCANS-Made up of only 1 type of -Made up condensation of2 or monosaccharide monomers more types of monosaccharides-For eg starch, glycogen, - For eg Hyaluronic acid, agar, cellulose Chitin, peptidoglycans etc-Glucan (made up of glucose)-Fructan(made up of fructose)-Galactan (made up of galactose)
  21. 21. STORAGEPOLYSACCHARIDES STARCH1. Carbohydrate reserve of plants and the most important dietary source for animals2. High content of starch in cereals, roots, tubers, vegetables etc.3. Homopolymer made up of GLUCOSE units. Also called as GLUCAN.4. Starch = Amylose + Amylopectin (polysaccharide components) GLYCOGEN1. Carbohydrate reserve in animals. Hence referred as animal starch2. High concentration in Liver, muscles and brain.3. Also found in plants that do not have chlorophyll (yeast and fungi)4. GLUCOSE is the repeating unit. INULIN1. Polymer of fructose i.e. fructosan2. Found in Dahlia, bulbs, garlic, onion etc3. Easily soluble in water4. Inulin is not readily metabolised in the human body and is readily filtered through the kidney. Hence used for testing kidney function (GFR) dr.aarif
  22. 22. STRUCTURALPOLYSACCHARIDES CELLULOSE1. Occurs exclusively in plants and is the most abundant organic substance in plant kingdom.2. Predominant constituent of plant cell wall.3. It is totally absent in animals. CHITIN1. Second most abundant organic substance.2. Complex carbohydrate of Heteropolysaccharide type.3. Found in the exoskeletons of some invertebrates like insects and crustaceans. Provides both strength and elasticity.4. Becomes hard when impregnated with calcium carbonate. dr.aarif
  23. 23. Proteins dr.aarif
  24. 24. PROTEINS Most abundant organic molecules of the living system. They form about 50% of the dry weight of the cell. They are most important for the architecture and functioning of the cell. Proteins are polymers of amino acids Proteins on complete hydrolysis yields Amino Acids There are 20 standard amino acids which are repeatedly found in the structure of proteins – animal, plant or microbial. Collagen is the most abundant animal protein and Rubisco is the most abundant plant protein Protein Synthesis is controlled by DNA. dr.aarif
  25. 25. AMINO ACIDS Amino acids are group of organic compounds having 2 functional groups (-NH2) and (-COOH) (-NH2) group is basic whereas (-COOH) is acidic R- can be H in glycine, CH3 in alanine, Hydroxymethyl in serine in others it can be hydrocarbon chain or a cyclic group All amino acids contain C, H, O and N but some of them additionally contain S Physical and chemical properties of amino acids are due to amino, carboxyl and R functional groups Amino acids are differentiated into 7 groups dr.aarif
  26. 26. No. Nature Amino acids1. NEUTRAL : Amino acids with 1 amino and 1 Glycine (Gly), Alanine (Ala), carboxyl group Valine (Val), Leucine (Leu), Isoleucine (Ile)2. ACIDIC : 1 extra carboxyl group Aspartic acid (Asp), Asparagine (Asn), Glutamic acid (Glu), Glutamine (Gln)3. BASIC : 1 extra amino group Arginine (Arg), Lysine (Lys)4. S – CONTAINING : Amino acids have sulphur Cysteine (Cys), Methionine (Met)5. ALCOHOLIC : Amino acids having –OH group Serine (Ser), Threonine (Thr), Tyrosine (Tyr)6. AROMATIC : Amino acids having cyclic Phenylalanine (Phe), structure Tryptophan (try)7. HETEROCYCLIC : amino acids having N in Histidine (His), Proline (Pro) ring structure dr.aarif
  27. 27. Alanine (neutral) Aspartic acid (acidic) Lysine (basic)Serine (alcoholic) Cysteine (suphur) Phenylalanine (aromatic) dr.aarif
  28. 28. PEPTIDE FORMATION Amino acids are linked serially by peptide bonds (-CONH-) formed between the (-NH2) of one amino acid and the (-COOH) of adjacent amino acid Chain having 2 amino acids linked by a peptide bond is called as a DIPEPTIDE The sequence of amino acids present in a polypeptide is specific for a particular protein. dr.aarif
  29. 29. 4 basic structural levels are assigned to STRUCTURE OF proteins – primary, secondary, tertiary PROTEIN and quaternary PRIMARYThe primary structure refers to the numberand linear sequence of amino acids in thepolypeptide chain and the location of thedisulphide bridgesThe primary structure is responsible for thefunction of the protein.The N-terminal amino acid is written on theleft side whereas the C- terminal amino acidis written on the right side dr.aarif
  30. 30. The folding of the linear chain into a specific coiled structure is called as secondary structure.SECONDARY 3 types : α- helix, β- pleated sheet and collagen helix α- helix β- pleated sheet Collagen helix dr.aarif
  31. 31. TERTIARYThe helical polypeptide may fold upon itself and assume a complex but specific form – spherical, rod like or something in between.These geometrical shapes are known as tertiary (30) structure QUATERNARY Proteins are said to be quaternary in structure If they have 2 or more polypeptide chains Haemoglobin is an excellent example dr.aarif
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  33. 33. PROTEINSFunction Nutritional Chemical nature importance and solubility dr.aarif
  34. 34. Structural proteins e.g. keratin, collagen Enzymatic proteins e.g. pepsinFunctional classification Transport proteins e.g. Haemoglobin Hormonal proteins e.g. Insulin, Growth hormone Contractile proteins e.g. Actin, myosin Storage proteins e.g. Ovalbumin Genetic proteins e.g. Nucleoproteins Defence proteins e.g. Imunoglobulins Receptor proteins e.g. for hormones and viruses dr.aarif
  35. 35. Classification based on chemical nature and solubility1. Simple proteins : They are composed only of amino acid residues2. Conjugated proteins : Along with amino acids , there is a non-protein prosthetic group.3. Derived proteins : They are denatured or degraded products of the above two dr.aarif
  36. 36. Proteins Simple Derived Conjugated NucleoproteinsGlobular Fibrous Glycoproteins Primary Secondary Coagulated Mucoproteins proteins Proteoses Albumin Collagen Lipoproteins Proteans protones Globulin Elastin Phosphoproteins Metaproteins Peptides Histones Keratin Chromoproteins Metalloproteins
  37. 37. LIPIDSWith the water, I say, Touch me not, To the tongue, I am tasteful, Within limits, I am dutiful, In excess, I am dangerous dr.aarif
  38. 38. Lipids are the chief concentrated storage form of energy forming about 3.5% of the cell content.Lipids are organic substances relatively insoluble in water butsoluble in organic solvents (alcohol, ether)Functions :1. They are the concentrated fuel reserve of the body.2. Lipids are constituents of membrane structure and regulate the membrane permeability.3. They serve as source of fat soluble vitamins4. Lipids are important cellular metabolic regulators5. Lipds protect the internal organs and serve as insulating materials dr.aarif
  39. 39. LIPIDS Simple Derived Complex Steroids Phospholipids TerpenesFats & Oils Waxes Glycolipids Lipoproteins dr.aarif
  40. 40. SIMPLE LIPIDSThey are esters of fatty acids with alcohol. They are of 2 types : 1. Neutral or true fats : Esters of fatty acids with glycerol 2. Waxes : Esters of fatty acids with alcohol other than glycerol. Neutral / True fatsTrue fats are made up of C, H, & O but O is lessA fat molecule is made up of 2 components :a) GLYCEROLb) FATTY ACIDS (1-3 mol, of same or diff long chained) dr.aarif
  41. 41. GlycerolA glycerol mol has 3 carbons each bearing a–OH groupFatty acidA fatty acid mol is an unbranched chain of C-atoms.It has a –COOH group at one end and a Hbonded to almost all the C-atomsFatty acids may be saturated or unsaturated dr.aarif
  42. 42. WAXESLipids which are long chain saturated fatty acids and a long chainSaturated alcohol of high mol wt other than glycerolExample :1. Bees wax : secretion of abdominal glands of worker honey bees2. Lanolin or wool fat : Secretion of cutaneous glands and obtained from the wool of sheep3. Sebum : secretion of sebaceous glands of skin4. Cerumen : soft and brownish waxy secretion of the glands in the external auditory canal. Also called as Earwax5. Plant wax : Coating formed on the plant organs to prevent transpiration6. Paraffin wax : A translucent waxy substance obtained from petroleum dr.aarif
  43. 43. They are derivatives of simple lipids having COMPLEX additional group like phosphate, N2-base, LIPIDS Protein etc. They are further divided into Phospholipids, Glycolipids, Lipoproteins.Phospholipid They are made up of a molecule of glycerol Or other alcohol having 1. A phos group at 1 of its –OH groups 2. 2 fatty acid molecules at other 2 –OH groups 3. A nitrogen containing base attatched to phos group A phospholipid molecule has a hydrophobic tail (fatty acids) and a hydrophilic head(phos group) dr.aarif
  44. 44. GlycolipidThey are components of cellmembranes, particularly myelinsheath and chloroplast membranesCEREBROSIDE are the mostsimplest form of glycolipids dr.aarif
  45. 45. LipoproteinThey contain lipids and proteins in their molecules.They are main constituent of membranes.They are found in milk and Egg yolk.Lipids are transported in blood and lymph as lipoproteins.5 types of lipoproteins : 1. chylomicrons 2. VLDL 3. LDL 4. HDL 5. Free fatty acid albumin complex dr.aarif
  46. 46. They are derivatives obtained on theDERIVED hydrolysis of the simple and complex lipids. LIPIDS e.g. steroids, terpenes and prostaglandins Steroid The steroids do not contain fatty acids but are included in lipids as they have fat-like properties. They are made up of 4 fused carbon rings Cholesterol, Vit D, testosterone, adrenocortical hormones. The most common steroids are STEROLS. Common sterols are Cholesterol and ergosterol dr.aarif
  47. 47. TerpenesTerpenes are a major component of essential oils produced byplants. They give fragrance to the plant parts.Vitamins A, E and K contain a terpenoid called phytolCarotenoid pigment is precursor for Vitamin ALycopene, a pigment present in tomatoes is a terpenoidGibberellins, the plant hormone is also a terpene dr.aarif
  48. 48. ENZYMES dr.aarif
  49. 49. Enzymes are a group of catalysts functioning in a biological systemThey are usually proteinaceous substances produced by the living cellWithout themselves getting affected.Enzymes enhance the rate of reaction and are formed in the cellunder the instructions of genesENZYMOLOGY is the branch of science that deals with the study ofEnzymes in all the aspects like nomenclature, reactions andfunctionsEnzymes occur in colloidal state and are often produced in inactiveform called proenzymes (zymogen), which are converted to theiractive forms by specific factors like pH, substrate etc.The enzymes that are produced within a cell for metabolicactivities are known as endoenzymes and those which act awayfrom the site of synthesis are called exo-enzymes dr.aarif
  50. 50. GENERAL PROPERTIES OF ENZYME AND FACTORS AFFECTING THEIR ACTIVITY1) Enzymes accelerate the reaction but do not initiate it.2) Enzymes themselves do not participate in the reaction and remainunchanged at the end of the reaction. Enzymes, are therefore,needed in small amounts.3) The molecule of an enzyme is larger than that of substrate molecule and hence during reaction a specific part of enzyme molecule comes in contact with the substrate molecule. That part is called active site of enzyme.4) Amphoteric nature: Chemically most of the enzymes are proteinsand, therefore, show amphoteric nature. The enzymes can react withacidic substances as well as alkaline substances. dr.aarif
  51. 51. 5) Specificity: Most of the enzymes are specific in their action. A single enzyme acts upon a single substrate or a group of closely related substrates. For example, the enzyme urease can act only upon ureainvertase can act upon sucrose only A slight change in the configuration of the substrate moleculerequires action by a different enzyme.6) Colloidal nature: All enzymes are colloidal in nature and thusprovide large surface area for reaction to take place. Colloids(colloids- gel like) are mixtures of two components i.e. dispersedparticles and dispersion medium. The size of the dispersedparticles is larger than dispersion medium. dr.aarif
  52. 52. 7) Enzyme optima : Enzymes generally work best under certain narrowly defined conditions referred to as optima. These include appropriate temperature and PH.a) Temperature sensitivity : Since the enzymes are proteins, they are affected by change in temperature. With increase in temperature, increase in enzyme activity takes place (up to 40 C). However, when temperature increases above 60 C the proteins undergo denaturation or even complete breakdown. When the temperature is reduced to freezing point or below freezing point the enzymes become inactivated but they are not destroyed. The rate of reaction is more at optimum temperature.b) pH sensitivity : Most of the enzymes are specific to pH andremain active within particular range of pH. The strong acid or strongbase denatures enzymes. Most of the intracellular enzymes functionbest around neutral pH dr.aarif
  53. 53. 8) Concentration of enzyme and substrate : The rate ofreaction is proportionate to the concentration of the reactingmolecules. If the substrate concentration is increased the rate ofenzyme action also increases up to certain limit. Beyond a certainconcentration, the enzyme molecules remain saturated with substratemolecules and the activity becomes steady.9) Enzyme inhibitors : Enzyme inhibitors are certain productswhich inhibit enzyme activity. During the reaction, if the active siteof enzyme is occupied by these inhibitors instead of substratemolecules and the activity of enzyme is lost. These substances arelike substrate molecules in their structure and are calledcompetitive inhibitors. dr.aarif
  54. 54. Group of Enzymes Reactions catalysed Examples1. Oxidoreductases Transfer of O2 or H2 atoms Dehydrogenase or electrons from one Oxidases substrate to another2.Transferases Transfer of a specific group Transaminase from one substrate to another3.Hydrolases Hydrolysis of a substrate Digestive enzymes4. Isomerases Change of the molecular Phospho Hexo form of the substrate isomerase5.Lyases Non hydrolytic removal or Decarboxylase addition of a group to a Aldolase substrate6. Ligases Joining of 2 molecules by Citric acid formation of new bonds synthetase dr.aarif
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