Chapter 1 - Chapter 1: The Genetic Approach to Biology I)...

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Chapter 1: The Genetic Approach to Biology I) Inheritance system (DNA) must have: A) Diversity of structure—capable of existing in many diff forms B) Ability to replicate C) Mutability D) Translation II) Genes—basic elements of system of inherited info, located on different spots along the chromosomes A) Genome—collection of all the genes in an organism B) Genetics—concerned with diversity, replication, mutation, and translation of the info in genes 1) Evolutionary change—due to different rates of reproduction of individual organisms having different heritable characteristics 2) Changes in populations frequency when different variants represented in successive generations III) Proteins—basis of structure of organisms and their active physiological processes A) Information for synthesis in DNA 1) Adenine=Thymine 2) Guanine=Cytosine B) Transcription 1) DNA double helix separated 2) One strand becomes template for a complementary RNA sequence called transcript (U=A) 3) Transcript altered by cutting out stretches of original that don’t encode for amino acids to produce MRNA 4) Production of transcripts: a) Increases # of copies of genetic info available to cell at any time b) mRNA relieves problem of traffic congestion—leaves immediate vicinity of genes and goes to cytoplasm c) Stability and lifetime of message molecules act as controls on how much of a particular protein will be produced C) Translation 1) mRNA is read in successive groups of three nucleotides (codons) 2) tRNA contain correspondence between codons and AA a) When attached to amino acid is charged b) Pair appropriate codon on mRNA c) Can be recharged with more amino acids so it can be reused 3) Takes place on ribosome D) Proteins are folded polypeptide chains 1) Cell makes chemical alterations in amino acids in molecule 2) Final folding depends on conditions in cell incl. presence of other molecules IV) Gene regulation A) Most DNA has a regulatory function 1) Occurs in attachment of RNA polymerase
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2) Occurs in the initiation of RNA polymerase movement along the DNA sequence
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Chapter 1 - Chapter 1: The Genetic Approach to Biology I)...

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