Dna presentation

dna

1. DNA Structure & Replication Patel krinal S Environmental Science Msc Sem.-I Roll No.-313

2. Contents What is the DNA? DNA Structure DNA replication Types of replication

3. What is the DNA ? Found in almost all cells contained phosphorus in the form of phosphate Double stranded molecule Double helix structure Made by nucleotide

4. DNA STRUCTURE

5. DNA STRUCTURE DNA has three main components: 1. Deoyribxose (a pentose sugar) 2. Nitrogen base 3. phosphate group

6. 1. Deoxyribose sugar Deoxyribose is a pentose monosacchride, a pentose sugar has five carbon atoms. D eoxyribose found in DNA ,is a modified sugar, lacking one oxygen atom .

7. 2. Nitrogen base They are divided into two groups Pyrimidines and Purines Pyrimidines 1.Thymine 2. Cytosine Purines 1.Adenine 2.Guanine

8. 3.Phosphate group A deoxyribos-phosphate backbone joins together nucleotides in a DNA sequence This backbone is composed of alternating sugar and phosphate groups

9. Nucleosides & Nucleotide A nucleoside consist simply of a nitrogen base and a five carbon sugar. A nucleotide is composed of a nitrogen base ,a five carbon sugar and one or more phosphate groups.

10. DNA Replication Steps The separation of DNA strands Replication fork formation Binding of bases to each strand The termination of replication process

11. DNA Replication Fundamental processes occurring in all cell for transfer of genetic information to daughter cell. Each cell must replicate its DNA before division. DNA is copied during the S or synthesis phase of interphase . New cells will need identical DNA strands.

12. Conti… Must carry the information. Cracking the genetic code. Extreme the DNA replication is necessary is order to preserve the integrity of the genome in successive generation. Start from ‘origin’. Can be uni or bidirectional. Involves DNA templating. RNA primers required.

13. 1.Conservative 2.Semi-conservative 3.Dispersive There are three type of replication

14. Conservative The parental molecule directs synthesis of an entirely new double- stranded molecule, such that after one round replication. Both parental strands stay together after DNA

15. Semi-conservative It was proposed by Watson & Crick. The parent DNA strand separates into two Each strand serves as a template for new complementary strands. The new double helix is half original.

16. Dispersive Parental & daughter DNA are interspersed in both strands following. Parental DNA breaks up into small fragments which then synthesize complementary strands that is randomly.

17. https:// www.google.co.in https:// www.slideshare.net/namrta chhabra Guided By: Kajal Joshi References