Gene expression RNA and protein synthesis

Gene expression RNA and protein synthesis - o 5’ – UUC...

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Gene expression RNA and protein synthesis (chapter 13) DNA to protein RNA – ribonucleic acid o Usually single stranded o Uracil is substituted for thymine o Sugar is ribose RNA structure Transcription o DNA dependent RNA polymerase Antiparallel synthesis RNA o Messenger RNA (mRNA) o Ribosomal RNA (rRNA) o Transfer RNA (tRNA) Genetic codes o Codon Sequence of 3 bases in mRNA (triplet code) Each codon specifies one amino acid or it specifies punctuation (stop or start) Translation = polypeptide synthesis o mRNA associates with ribosomes o amino acids to be incorporated into the polypeptide are carried by tRNA molecules tRNA o anticodon – 3 bases complementary to the 3 bases of the mRNA o in previos examples, anticodon was 3’ – AAG – 5’ o 3’ – AAG – 5’(anticodon in tRNA)
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Unformatted text preview: o 5’ – UUC – 3’(codon in tRNA) • Aminoacyl-tRNA reaction catalyzed by aminoacyl-tRNA synthetase • Fig 13-3c pg 291 • Fig 13-14 p292 o GTP, GDP • The genetic code is redundant o There are 64 codons – but only 20 amino acids o Some codone are synonymous codons • The central dogma of genetics and molecular biology o NDA (replication) RNA protein (transcription) o Exception to unidirentional flow of information o Retroviruses – have reverse transcriptase enzyme • Control of gene expression o Consider a structural gene (gene that codes for a polypeptide) o Some genes are constitutive (always transcribes) o Other genes are regulated o Prokaryotes vs. Eukaryotes...
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This note was uploaded on 02/28/2009 for the course BIOLOGY 101 taught by Professor Martin during the Fall '08 term at Rutgers.

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