1. NUCLEIC ACIDS & NUCLEOTIDES

2. Learning Objectives State the role of nucleic acids.
State the composition and functions of nucleic acids.
State that nucleotides are composed of pentose sugar, bases and phosphate group.
Explain the structure of DNA. Explain the secondary structure of RNA.
Describe the functions of nucleic acid.
Explain the nucleotides of biological importance.

3. What are Nucleic Acids ?
Polymers or macromolecules present in all living cells.
Fundamental components of nucleic acids: pyrimidine & purine bases, pentose sugars (ribose and 2 deoxyribose) and phosphoric acid.

4. Essential Components of all viruses…

5. What are Nucleic Acids ?
Main function: storage, transmission & use of genetic information
Each chromosome is made up of long strand of DNA: 30,000 genes in 23 pairs chromosomes

6. DNA: Carrier of genetic information RNA: Transmits genetic information from DNA to protein-forming system of the cell

7. Pyrimidines of Nucleic Acids
Contain six membered ring with
2 nitrogen atoms
3 Major Pyrimidines found in Human:
Cytosine
Uracil
Thymine

8. Purines of Nucleic Acids
Consist of pyrimidine ring fused to an imidazole ring

9. NUCLEOSIDES
NITROGEN BASE + SUGAR
HETEROCYCLIC NITROGENOUS BASE + GLYCOSIDIC CARBON OF A SUGAR = NUCLEOSIDE
IF SUGAR IS RIBOSE = RIBONUCLEOSIDE OR RIBOSIDE
DEOXYRIBOSE = DEOXYRIBOSIDE

10. NUCLEOTIDES IS A PHOSPHATE ESTER OF NUCLEOSIDE
NITROGEN BASE + SUGAR + PHOSPHATE
IS A PHOSPHATE ESTER OF NUCLEOSIDE
E.g. Adenine 5’ deoxyribotide
Monomeric unit of nucleic acids

11. Monomer undergo HYDROLYSIS
NUCLEOTIDES
Monomer undergo HYDROLYSIS
Phosphoric acid
molecule
Nitrogen containing ring compound
Pentose

12. NUCLEOTIDES: on the basis of hydrolysis
2 Types of Nucleic Acids
D-2 deoxyribose (DNA)
Found in cells as the major component of the chromosomes of the nucleus
Chloroplasts of green plants
Mitochondria
Viruses
D-ribose (RNA)
Ribosomal RNA (ribosomes)
Soluble RNA
RNA messenger
Found in cytoplasm

13. STRUCTURE OF DNA
DNA chain consists of 2 strands of polynucleotide chains
Coiled around each other in the form of double helix
Nucleotides of DNA- connected by phosphate ester bonds
(form the backbone of each DNA strand)
The Base of one strand of DNA – bound by strong hydrogen bonds.

14. STRUCTURE OF DNA

15. The Base of one strand of DNA – bound by strong hydrogen bonds.
STRUCTURE OF DNA
The Base of one strand of DNA – bound by strong hydrogen bonds.

16. SECONDARY STRUCTURE OF RNA
FREE RNA occurs as s single polyribotide chain lacking a fixed secondary structure.
Each chain is free to fold back
upon itself many times in numerous ways.

17. FUNCTIONS OF NUCLEIC ACIDS
REPLICATION (DNA)
PROTEIN SYNTHESIS (RNA)
Cell divides
Genetic information contained in bases such as A, T, G and C
RNA has only one strand and does not replicate

18. NUCLEOTIDES OF BIOLOGICAL IMPORTANCE
Integral component of nucleic acids
Adenosine nucleotide coenzymes: AMP, ADP, ATP
ATP are body’s energy compounds.
Involved in various metabolic process: storage & release of energy from their phosphate bonds.
ADP & AMP: transfer agents for the phosphate group (oxidative phosphorylation).

19. NUCLEOTIDES OF BIOLOGICAL IMPORTANCE
6. ATP: sources of high energy phosphates
7. Cyclic AMP: involved in the activation of phosphorylation
8. Coenzyme A: required for a number of metabolic reactions in which organic acids are involved.