chapter no. 02, nucleic acid

Nucleic AcidDr. Aarab Khan Lund

Nucleic Acids• Nucleic acids are molecules that store information for cellular

growth and reproduction• There are two types of nucleic acids:

- deoxyribonucleic acid (DNA)-ribonucleic acid (RNA)

• A nucleotide consists of a nitrogenous base, a pentose sugar and a phosphate group:

Nitrogen Bases

Pentose Sugars• There are two related pentose sugars:

- RNA contains ribose- DNA contains deoxyribose

• The sugars have their carbon atoms numbered with primes to distinguish them from the nitrogen bases

Nucleosides and Nucleotides• Nitrogen base+Pentose Sugar =Nucleoside• Nitrogen base+Pentose Sugar+Phosphate group= Nucleotide

Types of Nucleotides

• Mononucleotide• Dinucleotide• Polynucleotide

DNA (Hereditary material)• Griffith• None virulent bacteria->Virulent bacteria.• Hershy and Chase• Bacteriophage-DNA-Host-more phages.• All nucleotides of DNA, phosphate and

deoxyribose sugars are always common but nitrogenous bases are different.

• Each DNA has specific sequences of nitrogenous bases. It encodes vaste amount of information

Gene Expression• Transcription and Translation.

Continue• Initiation of protein synthesis occurs when a mRNA attaches to

a ribosome.