This document provides a list of contents for a biochemistry textbook. It covers topics such as an introduction to biochemistry, biomolecules, cells, organelles, transport across cell membranes, and endocytosis and exocytosis. The key topics are cells as the basic unit of life, the structures and functions of major organelles like the nucleus, endoplasmic reticulum, and mitochondria. It also summarizes the different mechanisms of transport across the cell membrane, including passive transport by diffusion and facilitated diffusion, and active transport like primary and secondary active transport.

1. COMPILED AND EDITED BY:
Ms. PRINCY AGARWAL
ASSISTANT PROFESSOR, U. S. OSTWAL INSTITUTE OF
PHARMACY, MANGALWAD
BIOCHEMISTRY: AN INTRODUCTION

2. LIST OF CONTENTS
• Introduction to Biochemistry
– Biochemistry defined
– Principles of Biochemistry
– Objectives of Biochemistry
– Applications
– Importance of Biochemistry
• Biomolecules
– Introduction to Biomolecules
– Classification of Biomolecules
– Examples and Functions

3. LIST OF CONTENTS
• Cell as a basic unit
– What is cell?
– Types of Cell
– Difference between Prokaryotic and Eukaryotic cell
– Major Intracellular organelles
– Cell organelle – Structure v/s Functions
• Nucleus
• Endoplasmic Reticulum
• Ribosomes
• Lysosome
• Golgi apparatus
• Mitochondria
• Cell membrane/
Plasma membrane

4. LIST OF CONTENTS
• Transport Across Cell membrane
– Cell Membrane Architecture In Transport Across Cell Membrane
– Components of Cell membrane
– Mechanisms of transport through Cell membrane
• Passive Transport
– Simple Diffusion
– Facilitated Diffusion
• Active Transport
– Primary Active Transport
– Secondary Active Transport
• Endocytosis
– Pinocytosis
– Phagocytosis
• Exocytosis
– Constitutive Exocytosis
– Regulated Exocytosis

5. INTRODUCTION
• Biochemistry is the application of chemistry to the study
of biological processes at the cellular and molecular level.
• The term was introduced by German Chemist Carl
Newberg in 1903.
• It emerged as a distinct discipline around the beginning
of the 20th century when scientists combined chemistry,
physiology and biology to investigate the chemistry of
living systems by studying :
A. The structure and behaviour of the complex molecules
found in biological material and
B. The ways these molecules interact to form cells, tissues
and whole organism

6. INTRODUCTION Contd..
• Biochemistry has become the language of medicine
as it builds the basis of drug action, drug synthesis
and prevention of diseases.
• It includes the study of chemical nature of all living
matter from the smallest virus and microorganism to
the most complex and highly evolved human being.
• Knowledge of biochemistry is used to control
diseases, abnormal metabolism and the treatment of
deficiencies.

7. BIOCHEMISTRY Defined
Biochemistry is the branch of science concerned
with the chemical and physico-chemical processes
which occur within living organisms.
Or
It is the study of the chemistry of life processes.

8. PRINCIPLES OF BIOCHEMISTRY
• Cells (basic structural units of living organisms) are highly
organized and constant source of energy is required to
maintain the ordered state.
• Living processes contains thousands of chemical reactions.
Precise regulation and integration of these reactions are
required to maintain life.
• Certain important reactions E.g. Glycolysis is found in almost
all organisms.
• All organisms use the same type of molecules: CHO,
proteins, lipids & nucleic acids.
• Instructions for growth, reproduction and developments for
each organism is encoded in their DNA

9. OBJECTIVES OF BIOCHEMISTRY
• To study and understand the structure and properties
of substances:
a. Which constitutes the framework of cell and tissues.
b. Which enter the cell as sources of energy or leave the
cell as waste products.
• To study catalytic activity of enzymes.
• To study processes that convert diet into compounds
which are characteristics of the cells of a given species.
• To study about multifold energy requiring process of
the living cell.
• To study chemistry of inheritance.

10. Biochemistry finds its applications in
the field of:
• Medicine
• Agriculture
• Forensic
• Dentistry
• Anthropology
• Industrial Applications
• Environmental Applications etc.

11. IMPORTANCE OF BIOCHEMISTRY
• It deals with the structures and functions of cellular
components such as proteins, carbohydrates, lipids, nucleic
acids and other biomolecules.
• Biochemists use physical and chemical principles to explain
biology at the molecular level.
• Basic principles of biochemistry are common to all living
organism

12. BIOMOLECULES
• Just like cells are building blocks of tissues likewise
molecules are building blocks of cells.
• 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.
• Animal and plant cells contain approximately 10, 000
kinds of molecules (bio-molecules).
• Water constitutes 50-95% of cells content by weight.

13. BIOMOLECULES Contd….
• 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.
• Ions like Na+, K+ and Ca++ may account for another 1%.
• Almost all other kinds of biomolecules are organic (C, H,
N, O, P, S)
• The chemical properties of organic bio-molecules are
determined by their functional groups. Most biomolecules
have more than one.

14. Classification of Biomolecules
A. On the basis of Chemical Constituents:
• Minerals
• Gases
• Water
Inorganic
• Carbohydrates
• Lipids
• Amino acids
• Proteins
• Enzymes
• Nucleic acids
• Vitamins
Organic

15. Classification of Biomolecules
B. On the basis of Size:
Macromolecules
Large sized, High Mol. Wt.
Above 10000 Daltons
Found in the acid insoluble
pool
Carbohydrates
Lipids
Proteins
Nucleic acids
Micromolecules
Small sized, Low Mol. Wt.
Between 18 and 800
Daltons
Found in the acid soluble
pool
Minerals
Gases
Water
Sugars
Amino acids
Nucleotides

16. Examples of Biomolecules with
their Functions

17. CELL - AS A BASIC UNIT
What is cell ?
• The cell is the basic, structural and functional unit of
life or living organism.
• It was discovered by Robert Hooke and is the
functional unit of all known living organisms.
• It is the smallest unit of life that is classified as a living
thing, and is often called the building block of life.
Some organisms, such as most bacteria, are unicellular
(consist of a single cell).
• Other organisms, such as humans, are multicellular.
Humans have about 100 trillion cells;

18. Diagrammatic Representation of
an Animal Cell

19. Types of Cells
• The cells of the living kingdom may be divided into
two categories:
1. Prokaryotes (Greek: pro- before; karyon- nucleus): Lack
a well defined nucleus and possess relatively simple
structure. These include various bacteria.
2. Eukaryotes (Greek: eu- true; karyon- nucleus): possess
a well defined nucleus and are more complex in their
structure and function. The higher organisms (animals and
plants) are composed of eukaryotic cells.

20. Difference between Prokaryotic
and Eukaryotic cell

21. Diagrammatic Representation

22. Parts/ Components/ Major
Intracellular Organs/ Organelles of
cell
• Nucleus
• Endoplasmic Reticulum
• Ribosomes
• Lysosome
• Golgi apparatus
• Mitochondria
• Cell membrane/ Plasma membrane

23. 1. NUCLEUS
• It is spherical and largest part of
the cell.
• It contains Nuclear membrane,
Nucleoplasm, Nucleoli and
genetic material DNA.
• Nuclear membrane is continuous
with Endoplasmic Reticulum.
FUNCTIONS
i. It controls all cellular activities.
ii. It contains DNA, RNA and proteins.
iii. RNA helps in protein synthesis.
iv. DNA helps in production of chromosomes.
v. Marker enzyme is DNA polymerase which is a site of DNA to
RNA synthesis.

24. 2. ENDOPLASMIC RETICULUM
FUNCTIONS
i. It provides surface area for
number of chemical reactions.
ii. It helps in the synthesis of
steroids, proteins, etc.
iii. It provides a pathway for
transporting various chemical
substances.
iv. It helps to concentrate the
products of synthetic activities
of cell.
• It is a network of membrane continuous with nuclear membrane.
• It is of two types:
a. Smooth ER
b. Rough ER

25. 3. RIBOSOMES
• These are tiny granules present in
cytoplasm as well as on surface of
endoplasmic reticulum.
• It contains special type of RNA
called r-RNA.
FUNCTION
i. Ribosomes are the main site for
protein synthesis.

26. 4. LYSOSOME
• These are membranous
vesicles which contains
powerful digestive enzymes
which are capable of breaking
down many kinds of
molecules.
FUNCTIONS
i. It helps for intracellular
digestion.
ii. Autolysis
iii. Phagocytosis

27. 5. GOLGI APPARATUS
• It consists of 4-8 flattened bag
like channels stacked upon each
other.
• It is located near the nucleus.
FUNCTIONS
i. It helps in intracellular sorting
of proteins.
ii. It helps in packaging of
secretory products.

28. 6. MITOCHONDRIA
FUNCTIONS
i. It is the main site for synthesis and storage of ATP.
ii. It is the site for citric acid cycle, β-oxidation, urea cycle, ETS.
iii. It contains special DNA and is self-replicative.
iv. It performs the main function of conversion and transfer of cellular
energy.
• These are small intracellular
organelles and are known
as Power house of cells.
• It is bounded by inner
folded and outer smooth
membrane.
• Inner surface have many
cristae and are covered
with F1 particles.

29. 7. CELL / PLASMA MEMBRANE
• It surrounds the cell and separate it from other cells and external environment.
• It is composed of proteins, phospholipids, carbohydrates, minerals etc.
FUNCTIONS
i. It involves in transport of molecules in and out of the cells.
ii. It gives shape to the cell and covers and protects the cell and organelles.
iii. It helps in intracellular adhesion and communication.
iv. It forms channels of ER.
v. It can act as a physiological sieve.

31. Cell Membrane Architecture In
Transport Across Cell Membrane

32. Cell Membrane Architecture In
Transport Across Cell Membrane Contd….
• The cell membrane plays an important role in transport of
molecules. Because it acts as a semi-permeable barrier, allowing
specific molecules to cross while fencing the majority of
organically produced chemicals inside the cell.
• The cell membrane is not static but is dynamic in nature.
• Electron microscopic examinations of cell membranes reveal the
development of the lipid bilayer model (fluid-mosaic model)
proposed by Singer and Nicolson.
• The model consists of phospholipid, which has a polar
(hydrophilic) head and two nonpolar (hydrophobic) tails.
• These phospholipids are aligned tail to tail so the non-polar areas
form a hydrophobic region between the hydrophilic heads on the
inner and outer surfaces of the membrane.

33. • The cell membrane contains
about 49% of protein, 43%
lipids and 8% carbohydrates
in the form of Phospholipids
and Glycoproteins.
• These biological membranes
are semi-permeable in nature
that is their permeability
properties ensure that the
specific molecules and ions
readily enter the cell and the
waste products leave the cell.
• These movements of solutes into the cell are mediated through the
action of specific transport proteins that are present on the cell
membrane.

35. DIAGRAM REPRESENTING DIFFERENT
MODES OF MEMBRANE TRANSPORT

36. MECHANISMS OF TRANSPORT
THROUGH CELL MEMBRANE

37. 1. PASSIVE TRANSPORT OR
DIFFUSION
• It is the process by which molecules move across a membrane
without energy supplied by ATP since, the energy originates from
the ion gradient itself.
• It is of two types:
 Simple Diffusion
 Facilitated Diffusion
• Involves
movement from
higher to lower
concentration
i.e. along the
concentration
gradient.

38. SIMPLE DIFFUSION
• Through Channel
Protein and Lipid
Bilayer interstices.
• E.g.: Transport of O2,
CO2, N2, Ethanol, Urea
FACILITATED DIFFUSION
• Through Carrier Proteins.
• Uniport i.e. work by binding to one
molecule of substrate at a time to move
it along its concentration gradient.
• E.g.: Transport of Glucose and most of
the Amino acids

39. 2. ACTIVE TRANSPORT
• If a molecule moves against a
concentration gradient, an external
energy source is required. This
movement is referred to as Active
transport.
• According to the source of energy, it is
of two types:
 Primary Active Transport: Direct
need of ATP molecule.
 Secondary Active Transport:
Indirect need of ATP molecule.

40. Primary Active Transport:
The energy is derived directly
from hydrolysis of ATP. E.g.:
Transport of Na+, K+, Ca+2,
H+, Cl-.
Secondary Active Transport:
ATP provides the energy for
transport indirectly.
It is of two types: Symport and
Antiport.
PRIMARY AND SECONDARY ACTIVE
TRANSPORT

41. SECONDARY ACTIVE TRANSPORT
• It uses energy of an electrochemical gradient produced originally by primary
active transport process using ATP.
• It is classified into two types:
 Antiport or Counter Transport: In it each substance moves in opposite
direction. E.g.: Na+ - Ca+2, Na+ - H+.
 Symport or Co-Transport: In it both the substances move across the
membrane in the same direction. E.g.: Glucose - Na+, Amino acid - Na+.

42. 3. ENDOCYTOSIS
• There are two types of endocytosis:
 Pinocytosis: It is the cellular uptake of fluid and fluid contents. It is a
cellular drinking process. E.g.: Proteins, Polysaccharides and
Polynucleotides can enter the cells through this process.
 Phagocytosis: It involves ingestion of large particles such as viruses,
bacteria, cells, tissue debris or a dead cell. It occurs only in specialized cells
such as macrophages and some of the WBC’s.
• The process by
which cells take up
large molecules is
called endocytosis,
a specialized
function of Cell
membrane.

43. 4. EXOCYTOSIS
• Exocytosis are of two types:
1. Constitutive exocytosis: Secretory materials are continuously released without
requirement of any specific kind of signal.
2. Regulated exocytosis: Regulated exocytosis requires an external signal, on the
vesicles for release of components. E.g.: Secretion of neurotransmitter, hormones
and many other molecules.
• The process by which the cells
direct the contents of secretory
vesicles out of the cell
membrane is known as
exocytosis.
• These vesicles contain soluble
proteins to be secreted to the
extracellular environment, as
well as membrane proteins and
lipids that are sent to become
components of the cell
membrane.