Genetic Control of Cell Function PDF

Genetic control of cell function Around 30,000 genes in human Outside strands= phosphoric acid+ deoxyribose sugar Inside strands= 4 nitrogenous bases such as purines (AG) or pyrimidines (CT) bases determining the code of the genes Nucleotide= Phosphoric acid+deoxyribose+B...

Genetic control of cell function Around 30,000 genes in human Outside strands= phosphoric acid+ deoxyribose sugar Inside strands= 4 nitrogenous bases such as purines (AG) or pyrimidines (CT) bases determining the code of the genes Nucleotide= Phosphoric acid+deoxyribose+Base Ten pairs of nucleotides are present in each turn of the DNA helix Genetic code Three successive bases= a code word Transcription: DNA > RNA RNA synthesis RNA basic building blocks are same: except 1. ribose sugar 2. uracil instead of thymine pyrimidine base RNA nucleotides Activation of RNA nucleotides by 2 high energy phosphate bonds RNA polymerase first recognizes promoter of a gene  Short interfering RNA (siRNA) is small 20-25 nucleotide length and designed to interfere with specific gene expression mRNA=codons; tRNA= anti-codons Translation: formation of protein on the ribosomes by polyribosomes Each AA requires 4 high energy bonds to combine with one another by peptide linkage!! Control of gene function and biochemical activity of cells 1. GENETIC REGULATION 2. ENZYME REGULATION Promoter (TATA box or TATAAAA) Enzyme inhibition (negative TF: + OR – transcription factors feedback control) Enhancers Enzyme activation (e.g. cAMP activates glycogen breakdown to Hormones: signals from outside form more ATPs) the cells E.g. purine and pyrimidine formation uses both of the above mechanisms