The document discusses DNA structure and replication. It describes DNA as consisting of deoxyribose, phosphate groups, and organic nitrogenous bases bonded together. The DNA double helix structure was discovered by Watson and Crick. DNA in E. coli exists in a circular structure, and replication of this circular DNA results in the formation of an intermediate theta structure with replication forks or moving Y-junctions. DNA replication involves enzymes like DNA polymerases, ligases, helicases, topoisomerases, and primases working together to copy the DNA.

1. MANASMITA MAHARANA
ADM. NO.-08ABT/15

2. Deoxyribose nucleic acid

3. Nucleotide
Deoxyribose
Organic nitrogenous base
PO4
1.Purine or 2.Pyrimidine

6. 10
Adenine Thymine
Cytosine Guanine

7. PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
12

8. DNA – DOUBLE HELICAL STRUCTURE
WATSON and CRICK- Model

9. DNA – DOUBLE HELICAL STRUCTURE

15. E.Coli DNA
is a circle
DNA is replicated while
maintaining the integrity of
the circle. An intermediate
theta structure is formed
which is due to the
formation of replication eye.
one or two moving Y-junctions in the
circle Replication forks, which further
supports the Semiconservative
replication.

17. Introduction

18. continuous synthesis
• Okazaki fragments
• joined by ligases

20. DNA polymerases-
DNA ligase
Single-strand binding proteins-
RNA primase-
Topoisomerases
Helicase

23. Origin of Replication-Prokaryotes Origin of Replication -Eukaryotes

25. 1.Topoisomerase
Class I topoisomerases

26. Class II topoisomerases -
2.Dna Gyrase-

27. (4) SSBs
(3)DNA polymerase
(2) Primase
(1) DNA helicase

29. RNA Primase
RNA Primase

35. In prokaryotes:

36. In eukaryote