1. A General Introduction to the Science of Biochemistry

2.  Introduction:
 The term biochemistry (bios = life) was first introduced
by a German chemist Carl Neuberg in 1903.
 Definitions: It is the study of structure, composition
and function of chemical substances (biomolecules)
and vital chemical process occurring in organisms.
 Chemical processes occurring in living matter.

3.  The chemistry of life.
 Chemistry of living things.
 Biochemistry is a science concerning with chemical
nature and chemical behaviour of the living matter.
 It involve the studies related to the nature of chemical
constituents of living matter, their transformations in
biological systems and the energy changes associated
with these transformations

4.  The science in which chemistry is applied to the study
of living organisms and the atoms and molecules which
comprise living organisms.
 Biochemistry has to do with the pathways and chemical
reactions that take place within the body.
 deals with matter inside the living cell called
protoplasm

5.  As a discipline, biochemistry seeks to define at the
molecular level chemical mechanisms that explain how
living organisms assemble nutrients from
environmental sources and affect processes of growth,
reproduction, adaptation, and metabolism within the
confines and complexity of cellular environment.

6.  On a broad scale, biochemists ask and seek answers to
question such as following:
1. By what chemical mechanisms are nutrients used for
the growth of cells?
2. By what chemical mechanisms do cells reproduce?
3. What are the chemical mechanisms used by cells that
allow them to adapt to their environment?

7. 4. What are the chemical mechanisms used by cells to
metabolize nutrients for the extraction of energy and
the formation/assimilation of the building blocks that
are necessary to make them the unique entity that they
are?
 It is a laboratory based science that brings together
biology and chemistry.
 By using chemical knowledge and techniques,
biochemists can understand and solve biological
problems.

8.  Biochemistry, Molecular Biology and Genetics form
part and parcel of Biology and are overlapping in their
theories, techniques and approaches with some minute
differences.
 Biochemistry concerns chemical materials and essential
processes with reaction mechanisms, thermodynamics,
bond angles taking place in living organisms.

9.  Biochemist wants to understand the chemical basis of
biological systems.
 He or she uses physical and chemical methods to
investigate questions about how electrons, atoms and
molecules behave in biological systems
 Genetics is the study of genes and their effects, heredity
and genetic variation in living beings.
 Molecular genetics ( the study of structure and function
of genes at a molecular level) is the sub field of
molecular biology.

10.  Molecular biology looks at the molecular mechanisms
behind processes including the storage and transfer of
genetic information and the interactions among
biomolecules.
 a biochemist looks at interactions from the molecular
level and smaller whereas the molecular biologist looks
at interactions from the molecular level and larger.

11.  Branches of biochemistry:
 Modern biochemistry has two branches:
 Descriptive biochemistry and dynamic biochemistry.
 Descriptive biochemistry-concerned with the
qualitative and quantitative characterization of the
various cell components.
 dynamic biochemistry. concerned with the explanation
of nature and mechanism of the reactions involving
these cell components.

12.  With expansion of knowledge of biochemistry, Many
newer disciplines have been emerged from
Biochemistry such of Enzymology (study of enzymes),
Endocrinology (study of hormones) Clinical
Biochemistry (study of diseases), Molecular
Biochemistry (Study of Biomolecules and their
functions).
 Agricultural Biochemistry, Pharmacological
Biochemistry are also noteworthy.

13.  The chemical elements of life:
 Living and non-living matter: Both are made of
elements.
 Element is a species of atoms having the same number
of protons in their atomic nuclei (i.e. the same atomic
number, Z).

14.  Elements cannot be broken down to substances with
different properties.
 Elements can be broken down to atoms, but each of the
atoms will have the same properties! (i.e. the same
number of protons)
 Around two dozen of the 92 naturally occurring
chemical elements are essential to various kinds of
biological life

15.  carbon, hydrogen, nitrogen, oxygen, calcium, and
phosphorus make up almost 99% of the mass of living
cells due to their ability to form covalent bonds by
electron-pair sharing
 Rare elements on Earth are not needed by life (except
selenium and iodine)

16.  Ocean algae need bromine which is not required by
land plants and animals
 Plants need boron and silicon, but animals instead
require sodium.
 Atoms are held together by chemical bonds to form
molecules
 Molecule is the simplest unit of a chemical compound
that can exist independently.

17.  The bonding hydrogen, oxygen, nitrogen and other
atoms to carbon atom form organic compounds (having
carbon skeleton).
 Carbon-carbon bonds make chain of carbon atoms
which form the skeleton or backbone of large organic
molecules.
 The organic molecules characterize the structure and
function of the cell organelles.

18.  Role of carbon:
 Carbon is a central element to life because most
biological molecules are built on a carbon framework.
 The complexity of living things is facilitated by
carbon’s linkage capacity.
 Carbon has great bonding capacity due to its tetrahedral
structure
 Carbon’s outer shell has only four of the eight electrons
necessary for maximum stability in most elements.

19.  Carbon atoms are thus able to form stable, covalent
bonds with a wide variety of atoms, including other
carbon atoms.