rav65819_ch15_277-302

rav65819_ch15_277-302 - ; 15 1.2 m chapter Genes and How...

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;;;;;;;; 15 1.2 m μ chapter Genes and How They Work concept outline
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introduction 15.1 The Nature of Genes Garrod concluded that inherited disorders can involve specifc enzymes Beadle and Tatum showed that genes speciFy enzymes The central dogma describes inFormation flow in cells as DNA to RNA to protein 15.2 The Genetic Code The code is read in groups oF three Nirenberg and others deciphered the code The code is degenerate but specifc The code is practically universal, but not quite 15.3 Overview of Gene Expression Transcription makes an RNA copy oF DNA Translation uses inFormation in RNA to synthesize proteins RNA has multiple roles in gene expression 15.4 Prokaryotic Transcription Prokaryotes have a single RNA polymerase Initiation occurs at promoters Elongation adds successive nucleotides Termination occurs at specifc sites Prokaryotic transcription is coupled to translation 15.5 Eukaryotic Transcription Eukaryotes have three RNA polymerases Each polymerase has its own promoter Initiation and termination diFFer From that in prokaryotes Eukaryotic transcripts are modifed 15.6 Eukaryotic pre-mRNA Splicing Eukaryotic genes may contain interruptions The spliceosome is the splicing organelle Splicing can produce multiple transcripts From the same gene 15.7 The Structure of tRNA and Ribosomes
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Aminoacyl-tRNA synthetases attach amino acids to tRNA The ribosome has multiple tRNA-binding sites The ribosome has both decoding and enzymatic functions 15.8 The Process of Translation Initiation requires accessory factors Elongation adds successive amino acids Termination requires accessory factors Proteins may be targeted to the ER 15.9 Summarizing Gene Expression 15.10 Mutation: Altered Genes Point mutations affect a single site in the DNA Chromosomal mutations change the structure of chromosomes Mutations are the starting point of evolution Our view of the nature of genes has changed with new information YOU’VE SEEN HOW GENES SPECIFY TRAITS and how these traits can be followed in genetic crosses. You’ve also seen that the information in genes resides in the DNA molecule; the picture on the left shows the DNA that comprises the entire E. coli chromosome. Information in DNA is replicated by the cell and then partitioned equally during the process of cell division. The information in DNA is much like a blueprint for a building. The construction of the building uses the information in the blueprint, but requires building materials and, carpenters and other skilled laborers using a variety of tools and working together to actually construct the building. Similarly, the information in DNA requires nucleotide and amino acid building blocks, multiple forms of RNA, and many proteins acting in a coordinated fashion to make up the structure of a cell. We now turn to the nature of the genes themselves and
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rav65819_ch15_277-302 - ; 15 1.2 m chapter Genes and How...

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