What is biochemistry? Branches of biochemistry, Scope of Biochemistry

1. 26-Jan-20 Dr. Subir Kumar Mandal 1
Introduction to
BiochemistryDr. Subir Kumar
Mandal

2. Biochemistry & Medical Science
Biochemistry can be defined as the science concerned
with the chemical basis of life.
The cell is the structural unit of living systems. Thus,
biochemistry can also be described as the science concerned
with the chemical constituents of living cells and with
reactions and processes they undergo.
By this definition, Biochemistry encompasses large areas
of Cell biology, Molecular biology, and Molecular
genetics.
26-Jan-20 Dr. Subir Kumar Mandal 2

3. Division of Biochemistry
26-Jan-20 Dr. Subir Kumar Mandal 3

4. Knowledge of Biochemistry is
Essential to All Life Sciences
 The biochemistry of the nucleic acids lies at the heart of
genetics.
 Physiology, the study of body function, overlaps with
biochemistry almost completely.
 Immunology employs numerous biochemical techniques,
and many immunologic approaches have found wide use by
biochemists.
 Pharmacology and pharmacy rest on a sound knowledge
of biochemistry.
26-Jan-20 Dr. Subir Kumar Mandal 4

5.  Poisons act on biochemical reactions or processes; this is
the subject matter of Toxicology.
 Many workers in Microbiology employ biochemical
approaches almost exclusively.
 Biochemical approaches are being used increasingly to
study basic aspects of Pathology such as inflammation, cell
injury, and cancer.
 Biochemistry and Medicine are intimately related.
Health depends on a harmonious balance of biochemical
reactions occurring in the body, and disease reflects
abnormalities in biomolecules, biochemical reactions, or
biochemical processes.
26-Jan-20 Dr. Subir Kumar Mandal 5

6.  Biochemical approaches are often fundamental in
illuminating the causes of diseases and in designing
appropriate therapies. The judicious use of various
biochemical laboratory tests is an integral component of
diagnosis and monitoring of treatment.
 Medical students who acquire a sound knowledge of
Biochemistry will be able to understand the two central
concerns of the health sciences:
The understanding and maintenance of health;
The understanding and effective treatment of disease.
26-Jan-20 Dr. Subir Kumar Mandal 6

7. Chemistry of Life
26-Jan-20 Dr. Subir Kumar Mandal 7
 Life is a chemical process. All aspects of living
creatures have a chemical basis. An understanding
of life requires an understanding of the chemical
basis of life.

8. Chemistry of Life
The fundamental unit of matter is the “Atom”. Atoms
are composed of 3 subatomic particles protons (+),
neutrons, electrons (-)
Protons and neutrons are found in the nucleus.
Electrons are found in shells surrounding the nucleus.
Most atoms normally have an equal number of
protons(+) and electrons(-) and carry no charge.
26-Jan-20 Dr. Subir Kumar Mandal 8

9. Chemistry of Life
Atoms can form associations called Molecules. A water
molecule consists of an association of 2 hydrogen atoms
and 1 oxygen atom.
26-Jan-20 Dr. Subir Kumar Mandal 9

10. 26-Jan-20 Dr. Subir Kumar Mandal 10

11. 26-Jan-20 Dr. Subir Kumar Mandal 11

12. 26-Jan-20 Dr. Subir Kumar Mandal 12

13. Chemical Composition of Human
Body
26-Jan-20 Dr. Subir Kumar Mandal 13

14. Major Biomolecules of Body
Glycogen
Protein
Lipid
DNA
RNA
26-Jan-20 Dr. Subir Kumar Mandal 14

15. 26-Jan-20 Dr. Subir Kumar Mandal 15

16. System International Unit
The International System of Units (1979), universally
abbreviated SI (French Le Syste`me International
d’Unite´s), is the modern metric system of
measurement.
There are three classes of SI units- Base units,
Derived units & Supplemental unit.
26-Jan-20 Dr. Subir Kumar Mandal 16

17. SI Base unit
26-Jan-20 Dr. Subir Kumar Mandal 17
Quantity Name of unit Symbol
Length Meter m
Mass Kilogram kg
Time Second s
Temperature Kelvin K
Amount Mole m
Current Ampere A
Luminous Intensity Candela cd

18. SI Derived units
26-Jan-20 Dr. Subir Kumar Mandal 18
Quantity Name of Unit Symbol
Area Square meter m2
Volume Cubic meter m3
Concentration kg/L , mol/L, mole/kg kg/L , mol/L,
mol/kg
Pressure Pascal Pa
Energy Joule J

19. Supplemental units
Supplemental units e.g. for time- minutes, hours, day
etc.
Exception to SI unit
In some biomolecules SI units cannot be used, e.g.
Proteins, Enzymes, Hormones.
26-Jan-20 Dr. Subir Kumar Mandal 19

20. SI Unit conversion
26-Jan-20 Dr. Subir Kumar Mandal 20
Analyte MW Conversion factor
(MW/AW) ÷ 10
SI unit
Glucose 180 18 mg % ÷ 18 = mmol/L
Cholesterol 386 38.6 mg % ÷ 38.6 = mmol/L
Creatinine 113 11.3 mg % ÷11.3 = mmol/L
Urea/BUN 60/28 6/2.8 mg % ÷ 6 = mmol/L
Bilirubin 585 58.5 mg % ÷ 58.5 = mmol/L

21. Isotope
lsotopes are defined as the elements with same atomic
number (number of proton) but different atomic
weight (number of protons and neutrons).
Isotope comes from Greek word: iso means equal &
tope means place.
26-Jan-20 Dr. Subir Kumar Mandal 21

22. Isotope
lsotopes have revolutionized biochemistry when they
became available to investigators soon after Second
World War.
Isotopes are two types- Stable Isotopes & Unstable
Isotopes.
26-Jan-20 Dr. Subir Kumar Mandal 22

23. 26-Jan-20 Dr. Subir Kumar Mandal 23

24. Stable Isotope
Naturally occurring and do not emit radiations.
Stable isotopes can be identified by Mass
spectrometry or Nuclear magnetic resonance.
26-Jan-20 Dr. Subir Kumar Mandal 24

25. Stable Isotope
Many elements of low atomic weight have two or
more stable isotopes, e.g. Carbon - 12C, 13C;
Nitrogen - 14N, 15N; Oxygen - 16O, 17O, 18O; Sulfur
- 32S, 33S, 34S, 35S.
26-Jan-20 Dr. Subir Kumar Mandal 25

26. Unstable Isotope
Atoms that spontaneously release protons and
neutrons from its nucleus (electron also), are unstable
isotopes or radioactive isotopes.
Naturally occurring isotopes of heavy elements are
usually unstable e.g. Radium, Uranium.
They become stable by Radio active decay.
26-Jan-20 Dr. Subir Kumar Mandal 26

27. Radioactive Decay
It’s the spontaneous decomposition or disintegration of
an unstable isotope to become a stable isotope with
simultaneous emission of radiations (α, β, γ) and
formation of a new element.
Curie (ci) is the basic unit of radioactive decay.
26-Jan-20 Dr. Subir Kumar Mandal 27

28. Radioactive Decay
The radioactive decay gives rise to one of the
following 3 ionizing radiations-
 α-Rays: due to the emission of protons
 β-Rays: due to the emission of electrons
 γ-Rays: due to emission of high energy photons
26-Jan-20 Dr. Subir Kumar Mandal 28

29. Clinical Uses of Isotopes
Diagnostic uses: Iodine uptake test, RIA of hormones,
Organ scanning (bone scan, brain scan), Absorption
test (Iron, Vit. B12), Isotope renogram for GFR, RBC
life span measurement etc.
Therapeutic uses: Radiotherapy in treatment of
malignancy.
Measurement of volumes & spaces: ECF volume,
blood volume, plasma volume, RBC volume etc.
26-Jan-20 Dr. Subir Kumar Mandal 29

30. Clinical Uses of Isotopes
Measurement of regional blood flow: Cerebral blood
flow, coronary blood flow, renal blood flow etc.
Sterilization of medical instruments.
26-Jan-20 Dr. Subir Kumar Mandal 30

31. Hazards of Radioactive Isotopes
26-Jan-20 Dr. Subir Kumar Mandal 31