The document provides an in-depth overview of biomolecules, classifying them into carbohydrates, amino acids and proteins, lipids, and nucleic acids, explaining their structures, functions, and biological significance. It discusses the composition and types of carbohydrates, the building blocks of proteins, and the characteristics and roles of lipids including their classification and functions. Additionally, the text delves into nucleic acids, specifically DNA and RNA, their role in genetic information storage, and the importance of each type of biomolecule in living organisms.

1. BIOMOLECULES
BY
Dr.K.Shoba M.Sc.,M.Phil.,Ph.D
Assistant Professor,
Department of Biochemistry,
D.K.M College for Women
(Autonomous), Vellore,
Tamil Nadu, India.

2. INTRODUCTION
All living organism is a collection of organic
molecules. All living organisms are made of one or
more cells. The compounds present in cells are
composed of Carbon, hydrogen, oxygen, nitrogen,
Phosphorus, and sulphur. Nearly all the carbon
compounds found in cells are grouped under four
classess 1.Carbohydrates, 2.Aminoacids and
Proteins, 3.Lipids, 4.Nucleic acids. These are
collectively knows as Biomolecules.

3. DEFINITION
Bio molecules are molecules that occur
naturally in living organisms. Bio molecules include
macromolecular like proteins, carbohydrates, lipids
and Nucleic acids. It also includes small molecules
like primary and secondary metabolites and natural
products.
IMPORTANT BIOMOLECULES
1.Carbohydrates, 2.Aminoacids and Proteins, 3.Lipids
4.Nucleic acids.

6. INTRODUCTION :
1. carbohydrates are among the most widely
distributed compound in both plants and animals.
2. plant build carbohydrates from carbon dioxide by
photosynthesis.
3. Elements of carbohydrates are :Carbon, hydrogen
Oxygen.
DEFINITION
1. Carbohydrates are polyhydroxy aldehydes or
ketone and their derivatives or as substance that yield
one of these compounds on hydrolysis.

7. 2.Example: Glucose, Maltose.
CLASSIFICATION

8. MONOSAACHARRIDES :
1. Greek :Mono-single, saccharan-sugar)
2. simple sugar.
3.General formula :CnH2nOn.
4.They can't further hydrolysed.
5. Example: Glucose, fructose
Galactose.

10. DISSACHARIDES:
1. Dissacharides are the sugars which on
hydrolysis gives two molecules of monosacharides
these monosacharides may be same or different.
2.General formula: CnH2On-1.
3. General molecular formula : C12H22O11
4 Examples: Maltose lactose, sucrose.

12. POLYSACCHARIDES:
1. (Greek :Poly-many, saccharan-sugar).
2. carbohydrates that yield a large number of
monosacharide molecules i. e more than 10 are known
as polysaccharides.
3. The general formula : (C6H10O5) n.
4. Example : Starch, Cellulose.

16. AMINO ACIDS :
DEFINITION :
Amino acids are a group of organic
compounds containing two functional groups amino and
carboxyl.
The amino group (-NH2) is basic, while the
carboxylic group (-COOH) is acidic in nature.
Examples : Glycogen, Lysine,

17. POINTS :
1. The amino acids are the simplest units of a protein
molecules and they form the building blocks of protein
structure.
2. The amino acid present in our body is L-a-amino
acid.
3. General structure :

18. Nearly 20 standard amino acid are identified.

19. PROTEINS
INTRODUCTION :
1. The name protein was first suggested in1838
by a Swedish chemist called Berzelius.
2. The term protein is derived from a Greek word
called Proteios means Primary or holding first place.
3. Proteins are macromolecules composed of
amino acids.

20. DEFINITION :
Proteins are defined as complex nitrogenous
substances found in the protoplasm of all animal and
Plant cells.
Proteins are biopolymers containing large
number of amino acids joined to each other by
peptide bond.

21. PROTEINS CLASSIFICATION :
Proteins can be classified in several ways based on
their shape, size, solubility, function, and
composition. Proteins can be classified in four main
groups based on :
1. based on shape and size.
2. based on composition and solubility.
3. based on Biological functions.
4. based on Nutritional classification.

22. PEPTIDE FORMATION
When the two ends of
amino acids combined to
from peptide leaving
water molecules.
Two ends are :
1. amino group.
2. carboxylic group.

23. If a peptide bond is made up of 2 Amino acids
called Depeptide.
If a peptide bond is made up of 3 Amino acids
called Tripeptide.
If a peptide bond is made up of less than 10 amino
acids, it is called as Polypeptide.
These peptide bonds are rather strong and serve as
the cementing material between the individual amino
acids.

24. STRUCTURE OF PROTEIN :
Proteins are the polymers of L - a - amino acids.
protein structure can be classified into 4 levels of
organisations.
1. Primary structure.
2. Secondary structure.
3. Tertiary structure.
4. Quaternary structure.

25. PRIMARY STRUCTURE :
1. Primary structure of a protein refers to the number
and sequence of amino acids in the Polypeptide chains.
2. The primary structure of an protein is largely
responsible for its function.
3. In primary structure the proteins are linear and
unbranched.

26. SECONDARY STRUCTURE :
1. The conformation of Polypeptide chain by twisting
or folding is referred to as secondary structure.
2. Two types of secondary structure :
1. a - helix.
2. B - sheet.

28. TERTIARY STRUCTURE :
1. The tree dimensional arrangement of proteins
structure is referred to as Tertiary structure.
2. This type of arrangement ensures stability of
the molecule.
3. Proteins in this conformation is biologically active
and called native protein.

30. QUARTERNARY STRUCTURE :
1. When a protein consits of 2 or more peptide
chains held together by non - covalent interaction (like
hydrogen bonds) inter chain hydrophobic interaction, it
is referred to as Tertiary structure.

32. INTRODUCTION :
1. Lipids - The word lipid derived from a greek
word Lipos - fat.
2. Lipids are a heterogeneous group of
compounds. which are sparingly soluble in water, but
soluble in non - polar solvents(fat sovents) such as
acetone, ether, chloroform, and benzene.
3. They are commercially important in the form
of soaps, detergents, greases, and the various oils of
the paint industry.

33. ELEMENTS COMPOSED LIPIDS ARE:
1. Carbon, 2 Hydrogen, 3.Oxygen, 4.Nitrogen,
5. Phosphorus.
SOURCES :
Animal sources - Milk, egg, meat, liver, fish oils.
Plant sources - seeds, Nuts, oils.
DEFINITION :
Lipids are organic substances insoluble in water,
soluble in organic solvents (alcohol, ether etc,) actually
or potentially related to fatty acids and utilised by the
living cells.

34. CLASSIFICATION :
Bloor has proposed the classification of
lipids based on their chemical composition used in
the year
1943.
four major classification are:
1. Simple lipids or Homolipids.
2. Complex or compound or Heterolipids.
3. Derived lipids.
4. Miscellaneous lipids.

35. The lipids are present in the form of :
1. Fatty acids
2. Cholesterol
3. Steroids.
FATTY ACIDS :
They are carboxylic acids with hydrocarbon side chain.
They are the Simplest form of lipids.
.eg,triglycerides
Fatty acids are two types :
1. Saturated fatty acids.
2. Unsaturated fatty acids.
.
... . ... .. ... .. . ... ... ... ... … . ... ... ... ... ... ... ... ... ... ... ...
.

36. SATURATED FATTY ACIDS :
1. These are the fatty acids containing only single
bonds.
2. General molecular formula : CnH2n+1COOH.
3. Saturated fatty acids makes the fat solid.
4.Example: Stearic acid.
... ... ... ... ... .. ... ... .

37. UNSATURATED FATTY ACIDS :
1. These fatty acids containing one or more double
bonds.
2. General molecular formula : CnH2n+1COOH.
3. Saturated fatty acids makes the fat liquid.
4.Example - Linoleic acids.

38. STEROIDS :
1. Steroids are the derivatives of cholesterol.
2. steroids are the hormones synthesised by
adrenal cortex, testes, ovaries during pregnancy by
placenta.
3. steroids are formed from chemical compound
known as Sterol.

39. . 5. Nucleic acids

40. INTRODUCTION :
1. Nucleic acid were first reported by Miescher
in 1871.
2. They have high molecular weight.
3. Nucleic acids are colourless complex
compound which are made up of 3 units.
*Nitrogenous bases(Purine or pyrimidine).
* Sugar
* Phosphoric acid.
4.They are 2 types of nucleic acids :
*Ribo nucleic acid (RNA).

41. DEFINITION :
Nucleic acids are large molecules where genetic
information is stored. There are two types of nucleic
acids :Deoxyribonucleic acids known as DNA and
Ribonucleic acids known as RNA. The nucleic acid are
made of Nucleotides. DNA is organized into
chromosomes and found within the nucleius of our cells.
Examples : DNA, RNA.

42. DNA :
1. DNA - Deoxyribonucleic acids.
2. DNA is polymer of Deoxyribonucleotide.
3. Double stranded DNA was proposed by J. D
Watson, F. H. C Crick in 1953.
4. DNA is found in chromosome.
5. It contains Deoxyribo sugar.
6.Nitrogenous bases - Adenine pairs with Thymine,
Guanine pairs with Cytosine.
7. purine and pyrimidine bases are equal.
8. DNA is a genetic material in all organism.

43. RNA :
1. RNA - Ribonucleic acids.
2. RNA is a polymer of ribonucleotides.
3. RNA is present in the cytoplasm.
4. It contains Ribo sugar.
5.The nitrogenous bases - Adenine pairs with Uracil,
Guanine pairs with Cytosine.
6. RNA is single stranded.
7. Purine and pyrimidine bases are not equal.

44. RNA is of 3 types :
1. mRNA
2. tRNA.
3. rRNA.

46. BIOLOGICAL IMPORTANCE :
1. CARBOHYDRATES :
1. Glucose - The major storage form of energy (Glycogen).
2. Present as glycoproteins and glycolipids in the cell.
3. Deficiency of carbohydrates leads to ketosis, excessive
breakdown of proteins, fatigue, and decrease energy level.
4. problems like - nausea, dizziness, constipation, lethargy,
dehydration, bad breath, loss of appetite.
5. Form a cell wall in various bacteria.
2. Proteins :
1. Denaturation property of proteins help in clinical
laboratory, the protein free substances of blood such as

47. uric acids and drugs analysed by precipitating the proteins of
blood by the addition of certain acids.
2.Hormones - insulin, growth hormones.
3. Enzymes - amylase, catalase, urease.
4. Defence protein - antibodies.
5. The extreme lack of proteins - Kwashiorkor, osmotic
balance, swelling of gut, edema or retention of water.
3.LIPIDS :
1. They are hydrophobic, water repellent, resist by water.
2. Triglycerides primarily function as fuel reserve of animals.
3. Paraffin wax - adhesive, cosmetics, sealants, lubricants,
insecticide, uv protection, and food like chewing gums.
4. wax function as water repellents on the surface of some

48. leaves, on feathers, on cuticles of certain insects.
5. deficiency of lipids - Dry and scaly skin, feeling constant
cold, dry hair, hormonal problems, hair loss, deficiency of fat
soluble vitamins.
4. NUCLEIC ACIDS :
1. DNA they are repository of the genetic information
responsible for transmission of inherited characteristics from
parents to offsprings.
2. RNA - protein synthesis, correct assembly of amino acid.
3. Errors in Nucleic acids metabolism leads to 1.leschnyhan
syndrome,2.Hereditary xanthinuria,3. orotic aciduria,
4.Hypouricemia,5. Von girekers disease, 6.Reye’s syndrome.