2. Chemicals or molecules present in the living organisms are known
as Biomolecules
The sum total of different types of biomolecules, compounds and
ions present in a cell is called as cellular pool
Biomolecules are compounds of carbon.
Hence the chemistry of living organisms is organized around carbon
Carbon 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
4. BIOMOLECULES
Micro molecules Macromolecules
Small sized, low mol wt Large sized, high mol wt
Between 18 and 800 daltons Above 10000 daltons
Found in the acid soluble pool Found in the acid insoluble pool
Minerals Carbohydrates
Gases Lipids
Water Proteins
Sugars Nucleic acids
Amino acids
nucleotides
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5. The major complex biomolecules of cells
Biomolecule Building block Major functions
Protein Amino acid Basic structure and function
of cell
DNA Deoxyribonucleotide Hereditary information
RNA Ribonucleotide Protein synthesis
Polysaccharide Monosaccharide Storage form of energy
Lipids Fatty acids & glycerol Storage form of energy to
meet long term demands
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14. CARBOHYDRATES
Carbohydrates are the most abundant organic molecules in nature.
The term carbohydrate is derived from the French term
hydrate de carbone i.e. it is a hydrate of carbon or Cn(H2O)n
Carbohydrates are defined as organic substances having C, H & O
Wherein 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.
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15. CARBOHYDRATES
MONOSACCHARIDES OLIGOSACCHARIDES POLYSACCHARIDES
Basic units of carbohydrates Non crystalline, non soluble
They can be further
Cannot be hydrolysed into in water, tasteless, on
hydrolysed
smaller units hydrolysis gives mol of
monosaccharides
a. Based on the no. of a. Disaccharides e.g. starch , cellulose
C-atoms b. Trisachharides
a. Based on the type of c. Tetrasachharides
functional group
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16. MONOSACCHARIDES
Based 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
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17. Derivatives of Monosaccharides
1. Deoxy Sugars : Deoxygenation of ribose produces deoxyribose,
which is a structural component of DNA
2. 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 acid
4. Sugar alcohols : Reduction of aldoses or ketoses.
Glycerol and Mannitol.
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18. OLIGOSACCHARIDES
They are formed by condensation of 2-9 monosaccharides
Depending 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
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19. DISACCHARIDES
A disaccharide consists of 2 monosaccharide units (similar or dissimilar)
held together by a glycosidic bond
They are crysatalline, water soluble and sweet to taste.
MALTOSE : - is also called as malt sugar.
- made up of 2 glucose molecules
LACTOSE : - 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 acid
SUCROSE : -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
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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 of
the 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. STORAGE
POLYSACCHARIDES
STARCH
1. Carbohydrate reserve of plants and the most important dietary source
for animals
2. 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)
GLYCOGEN
1. Carbohydrate reserve in animals. Hence referred as animal starch
2. 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.
INULIN
1. Polymer of fructose i.e. fructosan
2. Found in Dahlia, bulbs, garlic, onion etc
3. Easily soluble in water
4. Inulin is not readily metabolised in the human body and is readily filtered
through the kidney. Hence used for testing kidney function (GFR)
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22. STRUCTURAL
POLYSACCHARIDES
CELLULOSE
1. 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.
CHITIN
1. 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.
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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.
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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
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26. No. Nature Amino acids
1. 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
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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.
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29. 4 basic structural levels are assigned to
STRUCTURE OF proteins – primary, secondary, tertiary
PROTEIN and quaternary
PRIMARY
The primary structure refers to the number
and linear sequence of amino acids in the
polypeptide chain and the location of the
disulphide bridges
The primary structure is responsible for the
function of the protein.
The N-terminal amino acid is written on the
left side whereas the C- terminal amino acid
is written on the right side
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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
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31. TERTIARY
The 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
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33. PROTEINS
Function Nutritional
Chemical nature importance
and solubility
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34. Structural proteins e.g. keratin, collagen
Enzymatic proteins e.g. pepsin
Functional 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
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35. Classification based on
chemical nature and
solubility
1. Simple proteins : They are composed only of amino acid
residues
2. 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
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37. LIPIDS
With the water, I say, Touch me not,
To the tongue, I am tasteful,
Within limits, I am dutiful,
In excess, I am dangerous
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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 but
soluble 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 vitamins
4. Lipids are important cellular metabolic regulators
5. Lipds protect the internal organs and serve as insulating materials
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40. SIMPLE LIPIDS
They 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
fats
True fats are made up of C, H, & O but O is less
A fat molecule is made up of 2 components :
a) GLYCEROL
b) FATTY ACIDS (1-3 mol, of same or diff long chained)
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41. Glycerol
A glycerol mol has 3 carbons each bearing a
–OH group
Fatty acid
A fatty acid mol is an unbranched chain of C-
atoms.
It has a –COOH group at one end and a H
bonded to almost all the C-atoms
Fatty acids may be saturated or unsaturated
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42. WAXES
Lipids which are long chain saturated fatty acids and a long chain
Saturated alcohol of high mol wt other than glycerol
Example :
1. Bees wax : secretion of abdominal glands of worker honey bees
2. Lanolin or wool fat : Secretion of cutaneous glands and obtained
from the wool of sheep
3. Sebum : secretion of sebaceous glands of skin
4. Cerumen : soft and brownish waxy secretion of the glands in the
external auditory canal. Also called as Earwax
5. Plant wax : Coating formed on the plant organs to prevent
transpiration
6. Paraffin wax : A translucent waxy substance obtained from
petroleum
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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)
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44. Glycolipid
They are components of cell
membranes, particularly myelin
sheath and chloroplast membranes
CEREBROSIDE are the most
simplest form of glycolipids
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45. Lipoprotein
They 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
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46. They are derivatives obtained on the
DERIVED 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
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47. Terpenes
Terpenes are a major component of essential oils produced by
plants. They give fragrance to the plant parts.
Vitamins A, E and K contain a terpenoid called phytol
Carotenoid pigment is precursor for Vitamin A
Lycopene, a pigment present in tomatoes is a terpenoid
Gibberellins, the plant hormone is also a terpene
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49. Enzymes are a group of catalysts functioning in a biological system
They are usually proteinaceous substances produced by the living cell
Without themselves getting affected.
Enzymes enhance the rate of reaction and are formed in the cell
under the instructions of genes
ENZYMOLOGY is the branch of science that deals with the study of
Enzymes in all the aspects like nomenclature, reactions and
functions
Enzymes occur in colloidal state and are often produced in inactive
form called proenzymes (zymogen), which are converted to their
active forms by specific factors like pH, substrate etc.
The enzymes that are produced within a cell for metabolic
activities are known as endoenzymes and those which act away
from the site of synthesis are called exo-enzymes
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50. GENERAL PROPERTIES OF ENZYME AND FACTORS
AFFECTING THEIR ACTIVITY
1) Enzymes accelerate the reaction but do not initiate it.
2) Enzymes themselves do not participate in the reaction and remain
unchanged 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 proteins
and, therefore, show amphoteric nature. The enzymes can react with
acidic substances as well as alkaline substances.
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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 urea
invertase can act upon sucrose only
A slight change in the configuration of the substrate molecule
requires action by a different enzyme.
6) Colloidal nature: All enzymes are colloidal in nature and thus
provide large surface area for reaction to take place. Colloids
(colloids- gel like) are mixtures of two components i.e. dispersed
particles and dispersion medium. The size of the dispersed
particles is larger than dispersion medium.
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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 and
remain active within particular range of pH. The strong acid or strong
base denatures enzymes. Most of the intracellular enzymes function
best around neutral pH
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53. 8) Concentration of enzyme and substrate : The rate of
reaction is proportionate to the concentration of the reacting
molecules. If the substrate concentration is increased the rate of
enzyme action also increases up to certain limit. Beyond a certain
concentration, the enzyme molecules remain saturated with substrate
molecules and the activity becomes steady.
9) Enzyme inhibitors : Enzyme inhibitors are certain products
which inhibit enzyme activity. During the reaction, if the active site
of enzyme is occupied by these inhibitors instead of substrate
molecules and the activity of enzyme is lost. These substances are
like substrate molecules in their structure and are called
competitive inhibitors.
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54. Group of Enzymes Reactions catalysed Examples
1. Oxidoreductases Transfer of O2 or H2 atoms Dehydrogenase
or electrons from one Oxidases
substrate to another
2.Transferases Transfer of a specific group Transaminase
from one substrate to
another
3.Hydrolases Hydrolysis of a substrate Digestive enzymes
4. Isomerases Change of the molecular Phospho Hexo
form of the substrate isomerase
5.Lyases Non hydrolytic removal or Decarboxylase
addition of a group to a Aldolase
substrate
6. Ligases Joining of 2 molecules by Citric acid
formation of new bonds synthetase
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