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NAJRAN UNIVERSITY College of Applied Medical Sciences. General Microbiology Course Lecture No. 6. By. Dr. Ahmed Morad Asaad Associate Professor of Microbiology. Bacterial Genetics. The nucleic acid is composed of: 1- Phosphoric acid
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NAJRAN UNIVERSITY College of Applied Medical Sciences General Microbiology Course Lecture No. 6 By Dr. Ahmed MoradAsaad Associate Professor of Microbiology
The nucleic acid is composed of: • 1- Phosphoric acid • 2- Sugar (pentose) residue: Ribose (in RNA) or deoxyribose (in DNA). • 3- Nitrogenous bases: • *- Purine bases {adenine (A) and guanine (G)} • *- Pyrimidine bases {thymine (T), cytosine (C) and uracil (U)}.
Bacterial chromosome Codon A in one chain – T in other chain Backbone of phosphate and deoxyribose groups C in one chain – G in other chain Hydrogen bonds between each pair of bases
DNA replication RNA primer 5’ G A T C C T T T C G A A 3’ 3’ C T A G G A A A G C T T 5’ 5’ G A T C C T T T C G A A 3’ 3’ C T A G G A A A G C T T 5’ RNA primer
Gene expression 5’ G A T C C T T T C G A A 3’ 3’ C T A G G A A A G C T T 5’ 5’ G A T C C T T T C G A A 3’ 3’ C T A G G A A A G C T T 5’ Transcription Messenger RNA (m RNA)
Translation • The m RNA passes out of the nuclear body and is associated with the ribosome to form a ribosomal template on which amino acids will be arranged. • Amino acids are carried by specific RNA molecule called transfer RNA (tRNA) • Each tRNA carries an amino acid by one end and recognizes a specific codon on the mRNA by a complementary triplet (anticodon) present on its other end. • After the process of lining up of amino acids is completed, the amino acids are joined by peptide bonds to form a polypeptide chain. Assembly of polypeptide chains to form proteins and macromolecules then occurs.