Download
the nucleic acids n.
Skip this Video
Loading SlideShow in 5 Seconds..
THE NUCLEIC ACIDS PowerPoint Presentation
Download Presentation
THE NUCLEIC ACIDS

THE NUCLEIC ACIDS

2 Vues Download Presentation
Télécharger la présentation

THE NUCLEIC ACIDS

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. THE NUCLEIC ACIDS Mrs Manisha Sane PGT Chemistry KV VSN NAGPUR

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

  3. 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

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

  5. PHOSPHATE SUGAR Ribose or Deoxyribose NUCLEOTIDE STRUCTURE NUCLEOTIDE

  6. O C5 C1 C4 C3 C2 Ribose is a pentose sugar

  7. DEOXYRIBOSE RIBOSE CH2OH CH2OH OH OH O O C C C C H H H H H H H H C C C C OH OH H OH Spot the difference

  8. Nitrogenous Bases Pyrimidines Purines Adenine Thymine Cytosine Uracil Guanine In DNA In RNA

  9. Purines & Pyrimidines in DNA Thymine Adenine Guanine Cytosine

  10. Watson & Crick Base pairing

  11. Nucleosides & Nucleotides

  12. P P P P P P 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.

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

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

  15. 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 • Thus the sister strands are complementary but not identical • The bases are joined by hydrogen bonds, individually weak but collectively strong.

  16. The Double Helix (1953) www.chem.ucsb.edu/.../images/WatsonCrick.jpg

  17. Functions Of DNA • Replication • Transcription • Translation • Protein Synthesis Function Of RNA • It controls protein synthesis.

  18. Biological Functions of Nucleic Acids:- • DNA is exclusively responsible for maintaining the identity of different species of organisms over millions of years. • DNA is the chemical basis of heredity and may be regarded as the reserve of genetic information. • A DNA molecule is capable of self duplication during cell division and identical DNA strands are transferred to daughter cells. • Another important function of nucleic acids is the protein synthesis in the cell. • Actually, the proteins are synthesised by various RNA molecules in the cell but the message for the synthesis of a particular protein is present in DNA.

  19. SEMI CONSERVATIVE DNA REPLICATION

  20. Replication Of DNA

  21. Translation • Translation is the second process of protein biosynthesis (part of the overall process of gene expression).Translation occurs in the cytoplasm where the ribosomes are located. Ribosomes are made of a small and large subunit which surrounds the mRNA. In translation, messenger RNA (mRNA) is decoded to produce a specific polypeptide according to the rules specified by the genetic code. This is the process that converts an mRNA sequence into a chain of amino acids that form a protein

  22. Protein Synthesis

  23. IMPORTANT TERMS • Codon---The Triplet of nucleotide coding a particular amino acid. Total 64,61 for inner amino acids and 3 for terminal amino acids. • Gene— Sequence of the nucleotides in DNA coding a particular protein. • Genetic code-- the relation between the nucleotide triplet and the amino acid. • Genetic code is Degenerate and more then one codons may code for same amino acids.

  24. The Genetic Code Triplet code AUG start codon Encodes methionine UAA, UAG, UGA stop codons • The language of RNA to the language of protein: The genetic code is a triplet code in which three nucleotides in RNA specify one amino acid in protein. • RNA consists of four "letters": A, U, G, and C. Protein consists of 20 "letters": the amino acids.

  25. DNA FINGERPRINTING