Nucleic Acids (DNA & RNA)

DNA & RNA

1. THE NUCLEIC ACIDS © 2007 Paul Billiet ODWS

2. Presented to; Ms. Husn-ul-Ma’ab Presented bY ; Ali Mansoor 933 Abdullah Yaqoob 928 Harry Hamid 915 Zeeshan 869 Suleman Sikandar 914 THE NUCLEIC ACIDS

3. Nucleic-Acids Nucleotides DNA Structure of DNA DNA as genetic material RNA Types of RNA Difference b/w DNA & RNA Content ;

4. Friedrich Miescher in 1869 Isolated what he called nuclein from the nuclei of pus cells Nuclein was shown to have acidic properties, hence it became called nucleic acid.

5. Two types of nucleic acid are found Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA)

6. 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

7. DNA as genetic material: The circumstantial evidence Present in all cells and virtually restricted to the nucleus The amount of DNA in somatic cells (body cells) of any given species is constant (like the number of chromosomes) The DNA content of gametes (sex cells) is half that of somatic cells. The mutagenic effect of UV light peaks at 253.7nm. The peak for the absorption of UV light by DNA

8. NUCLEIC ACID STRUCTURE Nucleic acids are polynucleotides Their building blocks are nucleotides

9. NUCLEOTIDE STRUCTURE PHOSPATE SUGAR Ribose or Deoxyribose NUCLEOTIDE BASE PURINES PYRIMIDINES Adenine (A) Guanine(G) Cytocine (C) Thymine (T) Uracil (U)

10. Ribose is a pentose C 1 C 5 C 4 C 3 C 2 O

11. RIBOSE DEOXYRIBOSE CH 2 OH H OH C C OH OH C O H H H C CH 2 OH H OH C C OH H C O H H H C Spot the difference

12. Purines & Pyrimidines Adenine Cytosine Guanine Thymine

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

14. ADDING IN THE BASES The bases are attached to the 1 st 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

15. Watson & Crick Base pairing

16. 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

17. 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

18. Ribonucleic Acid (RNA) RNA is much more abundant than DNA There are several important differences between RNA and DNA: - the pentose sugar in RNA is ribose, in DNA it’s deoxyribose - in RNA, uracil replaces the base thymine (U pairs with A) - RNA is single stranded while DNA is double stranded - RNA molecules are much smaller than DNA molecules There are three main types of RNA: - ribosomal (rRNA), messenger (mRNA) and transfer (tRNA)

19. Types of RNA

20. The Double Helix (1953)