Molecular genetics: it deals with the structure, composition, function and replication of chromosomes and genes, representing genetics material like DNA and RNA.

1. TOPIC:
•Historical background of molecular genetics.
•Genetic material in organisms
•Structure and properties of nucleic acid.
•DNA transcription and its regulation.
WELCOME
TO CLASS PRESENTATION OF
Cell and Molecular Genetics
PRESNTED BY:- VIPIN PANDEY

2. ∗ Molecular genetics: it deals with the structure, composition,
function and replication of chromosomes and genes, representing
genetics material like DNA and RNA.
Historical background of molecular
genetics.
YEAR SCIENTIEST CONTRIBUTION
1856 G.J. Mendel Transmission of genetic materials
1871 F.Meischer Isolate nucleic acid.
1888 W.Waldeyer Coined the term chromosome.

3. Historical background of molecular
genetics.
YEAR SCIENTIEST CONTRIBUTION
1941 Beadle and Tatum One gene –one enzyme hypothesis.
1952 Hershey and chase DNA is the genetic material.
1953 Watson and Crick Double helix model of DNA.
1954 Gammow Proposed the codon to be triplet.
1955 Benzer Fine structure of gene
1955 Conrat and willims RNA is the genetic material in TMV.
1955 Ochoa and coworkers In vitro synthesis of RNA.
1956 Kornberg and coworkers In vitro synthesis of DNA.
1958 Mselson and stahl Semi conservation replication of DNA.
1961 Jacob and monod Operon concept of gene regulation.
1970 H.G. Khorana in vitro synthesis of gene.

4. Historical background of molecular
genetics.
YEAR SCIENTIEST CONTRIBUTION
1977 Alwin and kemp Developed the northern blotting technique.
1977 Maxam and Gilbert Chemical method of DNA sequencing.
1983 McClintock Discovered the transposable element
1985 Saiki and Mulis Discovered the Polymerase chain reaction.
1986 Ruska Designing of first electron microscope.
1987 Sanford and coworkers Developed biolistic gene transfer method.
1990 Barton at al. Formal launch of human genome project.
1990 Wiliiams at al. Developed the RAPD technique.
1991 fodor Developed DNA microarray system.
1995 Vos at al. Developed the AFLP technique.
2001 Venter at al. Human genome project completed.

5. ∗ Any material of plant, animal, microbes or other living containing
functional units of heredity is called genetic material.
∗ Properties of genetic material:
∗ It is replicated with high fidelity.
∗ Its able to express itself.
∗ Its also able to store the highly variable information.
∗ Its allow errors in low frequency for the origin of new genetic
variation through mutation.
Genetic material in organisms

6. ∗ Nucleic acids were discovered by Meischer in 1871, and called
nuclein. The term nucleic acid was first used by altman in 1889.
∗ Nuclein was shown to have acidic properties, hence it became
called nucleic acid
∗Two types of nucleic acid are found
∗ Deoxyribonucleic acid (DNA)
∗ Ribonucleic acid (RNA)
Genetic material in organisms

7. ∗ The distribution of nucleic acids in the eukaryotic cell
∗ DNA is found in the nucleus
with small amounts in mitochondria and chloroplasts
∗ RNA is found throughout the cell
NUCLEIC ACID STRUCTURE
∗ Nucleic acids are polynucleotides
∗ Their building blocks are nucleotides
Genetic material in organisms

8. Genetic material in organisms
NUCLEOTIDE STRUCTURE
PHOSPATE SUGAR
Ribose or
Deoxyribose
NUCLEOTIDE
BASE
PURINES PYRIMIDINES
Adenine (A)
Guanine(G)
Cytocine (C)
Thymine (T)
Uracil (U)

9. Ribose is a pentose
C1
C5
C4
C3 C2
O

10. RIBOSE DEOXYRIBOSE
CH2OH
H
OH
C
C
OH OH
C
O
H HH
C
CH2OH
H
OH
C
C
OH H
C
O
H HH
C
Spot the difference

11. THE SUGAR-PHOSPHATE
BACKBONE
∗ The nucleotides are all orientated in the
same direction
∗ The phosphate group joins the 3rd
Carbon of one sugar to the 5th
Carbon
of the next in line.
P
P
P
P
P
P

12. ADDING IN THE BASES
∗ The bases are attached to the 1st
Carbon
∗ Their order is important
It determines the genetic information of the
molecule
P
P
P
P
P
P
G
C
C
A
T
T

13. DNA IS MADE OF TWO STRANDS OF
POLYNUCLEOTIDE
P
P
P
P
P
P
C
G
G
T
A
A
P
P
P
P
P
P
G
C
C
A
T
T
Hydrogen bonds

14. DNA IS MADE OF TWO STRANDS OF
POLYNUCLEOTIDE
∗ The sister strands of the DNA molecule run in opposite
directions (antiparallel)
∗ They are joined by the bases
∗ Each base is paired with a specific partner:
A is always paired with T
G is always paired with C
Purine with Pyrimidine
∗ This the sister strands are complementary but not
identical
∗ The bases are joined by hydrogen bonds, individually
weak but collectively strong

15. Purines & Pyrimidines
Adenine
CytosineGuanine
Thymine

16. Watson & Crick Base pairing

17. The Watson-Crick Structures

18. ∗ Transcription is a process through which a DNA sequence is
enzymatically copied by an RNA polymerase to produce a
complementary RNA.
∗ The main points related to transcription are listed below :-
1. Synthesis of RNA:- mRNA
2. Template used:- single strand of DNA.
3. Enzyme involved:- RNA polymerase, α, β, β’, and σ polypeptide
4.Genetic information copied:- DNA to mRNA.
5. Direction of synthesis. 5’--------->3’ direction.
DNA transcription and its regulation.

19. ∗ The mechanism of transcription consists of three major phases
or stages..
1. Initiation
2. Elongation
3. Termination
Mechanism of transcription.

20. Initiation

21. Initiation

22. Elongation

23. Elongation

24. Elongation

25. Termination

26. Termination

27. Termination

28. Termination

29. Termination

30. Transcription
Multiple RNA polymerase can be transcribe the same gene at the
same time.
A cell can synthesize a large number of RNA transcripts in short
time.

31. Self splicing by group ii introns

32. Self splicing by group ii introns

33. Self splicing by group ii introns

34. Self splicing by group ii introns

35. Self splicing by group ii introns

36. Self splicing by group ii introns

37. Transcription regulation
Transcription is regulated by activator protein its
regulate to RNA polymerase open and close complex.

38. Transcription regulation

39. Transcription regulation

40. Transcription regulation

41. Thank you