Biomolecules introduction

1. BIOMOLECULES
Dr. Harinatha Reddy
Assistant Professor
Department of Microbiology

2. • Chemical analysis on a plant tissue, animal tissue or a
microbial paste..
• we obtain a list of elements like
• carbon,
• hydrogen,
• oxygen
• and several others ..

3. • If the same analysis is performed on a earth’s crust as
an example of non-living matter:
• we obtain a similar list.
• However, carbon and hydrogen elements is higher in
any living organism than in earth’s crust..

4. The element present in highest concentration in body is : Oxygen
Lowest is : Si

5. What are biomolecules?
• All the carbon compounds present in living cell called
‘biomolecules
Biomolecules
Bio Macromolecules Bio Micromolecules
Proteins
Polysaccharides
Nucleic acids
Amino acids
Monosaccharide's
(Glucose, Fructose)
Nucleotides
Lipids
Vitamins Molecular weight:
18 to 800 daltons (Da)

6. How to analyse chemical composition?
(Cl3 CCOOH)
Living tissue

7. How to analyse chemical composition?
• We can take any living tissue (a vegetable or a piece of
liver, etc.)..
• and grind it in trichloroacetic acid (Cl3 CCOOH) using a
mortar and a pestle.
• We obtain a thick slurry.

8. • If we were to strain this through a cheesecloth or
cotton we would obtain two fractions.
• One is called the filtrate or, the acid-soluble pool,..
• The second, the retentate or the acid-insoluble fraction.
• Scientists have found thousands of organic compounds
in the acid-soluble pool.

9. • Analytical techniques, applied to the compound give us
an idea of the molecular formula and the probable
structure of the compound.

10.  However, living organisms have inorganic elements and
compounds in them.
 How do we know this?

11. • One weighs a small amount of a living tissue (say a leaf
or liver) and dry it.
• All the water, evaporates.
• The remaining material gives dry weight.

12. • Now if the tissue is fully burnt,..
• All the carbon compounds are oxidised to gaseous form
CO2 and water vapour are removed.
• What is remaining is called ‘ash.

13. • This ash contains inorganic elements:
• like calcium, magnesium etc.
• Inorganic compounds:
• like sulphate, phosphate, etc.
• Inorganic element and compounds are also seen in the
acid-soluble fraction.

14. Amino acids

15. Amino acids are organic compounds..
• Amino acids contain an amino group and Carboxylic
acid groups attached α-carbon.
• Hence, they are called α-amino acids.

16. • There are four substituent groups occupying the four
valency positions.
• These are hydrogen, carboxyl group, amino group and a
variable group designated as R group.

17. • Based on the nature of R group there are 20 amino
acids.
• Amino acids occur in proteins..

19. • The R group in amino acids could be a hydrogen (the
amino acid is called glycine),
• a methyl group (alanine),
• hydroxy methyl (serine), etc.

20. • The chemical and physical properties of amino acids are
essentially of the amino, carboxyl and the R functional
groups.
• Based on number of amino and carboxyl groups:
• Acidic: glutamic acid and Aspertic acid.
• Basic: lysine and Arginine.
• Neutral: valine, glycine, serine, alanine
• Aromatic : tyrosine, phenylalanine, tryptophan.

22. • A particular property of amino acids is the ionizable
nature of –NH2 and –COOH groups.
• Hence in solutions of different pHs, the structure of
amino acids changes.
• B is called zwitterionic form

23. Lipids

24. • Lipids are generally water insoluble.
• They could be simple fatty acids.
• A fatty acid has a carboxyl group attached to an R group.
• COOH----R
• The R group could be a methyl (–CH3 ), or ethyl (–C2H5 )
or higher number of –CH2 groups (1 carbon to 19
carbons).

25. • Palmitic acid has 16 carbons including carboxyl carbon.
• It is Saturated lipid.
• COOH—(CH2)14—CH3
• Arachidonic acid has 20 carbon atoms including the
carboxyl carbon.
• It is Unsaturated.
• COOH—(CH2)18=CH3

26. • Fatty acids could be saturated (without double bond)..
• Unsaturated (with one or more C=C double bonds).

27. • Another simple lipid is glycerol which is trihydroxy
propane.
• Many lipids have both glycerol and fatty acids.

28. • Here the fatty acids are found esterified with glycerol.
• They can be then monoglycerides, diglycerides and
triglycerides..

29. • Lipids are also called fats and oils based on melting
point.
• Oils have lower melting point (e.g., gingely oil) and
hence remain as oil in winters..

30. Some lipids have phosphorous
• These are phospholipids.
• They are found in cell membrane.
• Lecithin is one example.

31. • Some tissues especially the neural tissues have lipids
with more complex structures…

32. Carbohydrates
1. Monosaccharide's:
2. Disaccharides
3. Polysaccharides

33. Nitrogen bases

34. Nitrogen bases
• Two types of nitrogen bases
• Purines: (Adenine and Guanine)
• Pyrimidines: (Cytosine, Thymine and Uracil)

35. Nitrogen bases are heterocyclic rings
• When Nitrogen bases attached to a sugar, they are
called nucleosides.
• If a phosphate group is also found esterified to the
sugar they are called nucleotides.

36. • Nitrogen bases are: adenine, guanine, cytosine, uracil,
and thymine.
• Nucleosides: Adenosine, guanosine, thymidine, uridine
and cytidine.
• Nucleotides: Adenylic acid, thymidylic acid, guanylic
acid, uridylic acid and cytidylic acid.

37. Nucleic acids are DNA and RNA.
• DNA and RNA Polymer of nucleotides.
• DNA and RNA function as genetic material..

39. Primary and secondary metabolites

40. Primary metabolites:
• Biomolecules, have thousands of organic compounds
including amino acids, sugars, proteins, nucleic acids
etc.
• biomolecules also known as primary metabolites..
• Primary metabolites play known roles in normal
physiologial processes

41. Secondary metabolites
• Plant, fungal and microbial cells, have thousands of
compounds other than these called primary metabolites..
• alkaloids,
• flavonoids,
• rubber,
• essential oils,
• antibiotics,
• coloured pigments,
• scents,
• gums,
• spices.
• These are called secondary metabolites

42. • we do not at the moment, understand the role or
functions of all the ‘secondary metabolites’ in host
organisms.
• However, many of them are useful to ‘human welfare’
(e.g., rubber, drugs, spices, scents and pigments).
• Some secondary metabolites have ecological
importance.

44. THANK YOU::::::::