This document provides an overview of cell and molecular biology. It defines cells as the basic structural and functional units of life and describes their components and characteristics. The development of cell theory by Hooke, Leeuwenhoek, Schleiden, Schwann, and Virchow is summarized. Molecular biology is introduced as the study of gene structure and function at the molecular level, involving DNA, RNA, proteins, and their interactions. Common techniques used in molecular biology like PCR and DNA sequencing are listed.

1. CELL AND MOLECULAR BIOLOGY:
DEFINITIONS THEORY AND BASICS,
HISTORY AND APPLICATIONS
Dr. Pulipati Sowjanya
Professor & Head
Vignan Pharmacy College
Vadlamudi, Guntur (Dt)

2. CELLS
The cell (from Latin cella, meaning “small room”)
is the basic structural, functional and biological
unit of all known living organisms.
Cells are often called “building blocks of life”
Just like bricks are the building blocks of a house
or school, cells are the building blocks of life.
A cell is the smallest unit of life that can replicate
independently
The study of cells is called cell biology or cytology
One square centimeter of your skin’s surface contains over 100,000 cells

3. CELLS
Cells consist of cytoplasm enclosed within a membrane, which contains
many biomolecules such as proteins and nucleic acids.
Organisms can be classified as
Unicellular (consisting of a single cell; including bacteria) or
Multicellular (including plants and animals).
While the number of cells in plants and animals varies from species to
species, humans contain more than 10 trillion cells. Most plant and
animal cells are visible only under a microscope, with dimensions
between 1 and 100 micrometers.

4. SIZES OF LIVING THINGS

5. CELL THEORY
All organisms are composed of cells
All cells come only from pre-existing cells (Rudolf Virchow)
Cells are the smallest structural and functional unit of organisms
Cells carry genetic information in the form of DNA
Robert Hooke (1665) Antony van
Leeuwenhoek (1673)
Matthias Jacob
Schleiden (1838) plant
Theodor Schwann
(1839) animal

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THE DEVELOPMENT OF CELL THEORY
● In 1838 and 1839, a German botanist by the name of Matthias Schleiden and German
zoologist by the name of Theodore Schwann viewed plants and animals under a
microscope and discovered that plants and animals are both made of cells.
● In 1855 a Prussian (modern day German) physician by the name of Rudolph Virchow
collaborated his ideas with the other two scientists and they developed the Cell
Theory.
In 1855, a German doctor, Rudolf Verchow (FURkoh)
proposed that new cells are formed only from existing cells.
“All cells come from cells” wrote Virchow. The
observations and conclusions of Hooke,
Leeuwenhoek, Schleiden, Schwann, Virchow, and
others led to the development of the cell theory.
Rudolph Virchow

7. MOLECULAR BIOLOGY
Molecular biology is the study of “IT IS THE STUDY OF GENE
STRUCTURE AND FUNCTION AT MOLECULAR LEVEL”

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• Molecular biology is the branch of biology that
deals with the molecular basis of biolgical
activity.
• This field overlaps with other areas of biology and
chemistry, particularly genetics and biochemistry.
• It concerns itself with understanding and the
interactions between various systems of cells like
DNA, RNA and protein biosynthesis.
MOLECULAR BIOLOGY
Relationship of Molecular
Biology with other branches

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MOLECULAR BIOLOGY
• This field overlaps with other areas of biology and chemistry, particularly genetics and
biochemistry. Molecular biology chiefly concerns itself with understanding the interactions between
the various systems of a cell, including the interactions between DNA, RNA and protein
biosynthesis as well as learning how these interactions are regulated.
• Much of the work in molecular biology is quantitative, and recently much work has been done at the
interface of molecular biology and computer science in bioinformatics and computational biology.
• Since the late 1950s and early 1960s, molecular biologists have learned to characterize, isolate and
manipulate the molecular components of cells and organisms includes DNA, the repository of genetic
information; RNA a close relative of DNA; and proteins, the major structural and enzymatic type of
molecule in cells.

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Biochemistry: Is the study of chemical substances and vital processes
occurring in living organisms.
• The study of chemistry behind biological processes and the synthesis of
biologically active molecules are examples of biochemistry.
Genetics : Is the study of effect of genetic differences on organisms.
• The study of “mutants” organisms which lack one or more functional components
with respect to the so called “wild type” or normal phenotype.
Molecular biology: Is the study of molecular process of replication,
transcription,translation and cell function.
• The central dogma of molecular biology where genetic material is transcribed into
RNA and then translated into proteins.

11. COMPONENTS INVOLVE IN MOLECULAR
BIOLOGY
DNA
RNA
Protein

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Basic players in molecular biology: DNA, RNA, and proteins.

13. WARREN WEAVER
While molecular biology was established in the
1930s, the term was first coined by Warren
Weaver in 1938. Warren was the director of
Natural Sciences for the Rockefeller
Foundation..
Warren Weaver

14. WATSON AND CRICK
The structure of DNA was described by British Scientists Watson and
Crick as long double helix shaped with its sugar phosphate backbone
on the outside and its bases on inside; the two strand of helix run in
opposite direction and are antiparallel to each other. The DNA double
helix is stabilized by hydrogen bonds between the bases.

15. WATSON AND CRICK BUILDS A
MODEL DNA 7TH MARCH 1953
Watson and Crick – Awarded Nobel Prize in 1962

16. COMMON TOOLS OF MOLECULAR BIOLOGY
 Nucleic acid fractionation
Polymerase chain reaction
Probes, Hybridization
Vector, Molecular cloning
Nucleic acid enzymes
Microarray
DNA sequencing
Electrophoretic separation of nucleic acid
Detection of genes: DNA: Southern blotting
*RNA: Northern blotting
*Protein: Western blotting

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CURRENT USES OF MOLECULAR BIOLOGY
The most recent applied technologies, genetic
engineering, DNA finger-printing in the social and
forensic science, pre and postnatal diagnosis of inherited
disease, gene therapy and drug Design.
Molecular biology allows the laboratory to be predictive
in nature, it gives information that the patients may be at
risk for disease (future).
Major tool in Diagnosis of Infectious