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AP Biology: Chapter 18 Flashcards

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6313748852Feedback Inhibition- The product acts as an allosteric inhibitor of the 1st enzyme in tryptophan pathway but this is wasteful production of enzymes0
6313748853Gene Regulation- Don't block the enzyme's function, block transcription of genes for all enzymes in tryptophan pathway - Saves energy by not wasting it on unnecessary protein synthesis1
6313748854Operon- Genes grouped together with related functions2
6313748855Promoter- RNA polymerase binding site - Controls transcription of all genes in the operon - Transcribed as one unit and a single mRNA is made3
6313748856Operator- DNA binding site of repressor proteins4
6313748857Repressor Operon- Binds to DNA at the operator site - Blocking RNA polymerase - Blocks transcription - Similar to how a skateboard stops on a curb - ANABOLIC pathways (build) - Synthesizing end products - Cell allocates excess resources to other uses5
6313748858Inducible Operon- CATABOLIC pathways (destroy) - Digesting nutrients to simpler molecules - Produce enzymes only when nutrients are available - Cell avoids making proteins that have nothing to do, allocates resources6
6313748859DNA Packing- DNA coiling and folding - Degree of packing regulates transcription - No transcription, genes off - Wrapped histones - Double helix - Nucleosomes (beads on a string) - Chromatin fiber - Looped domains - Chromosome7
6313748860DNA Methylation- Blocks transcription factors and genes turned off - Attachment of methyl groups to cytosine - Nearly permanent inactivation of genes - Ex: Barr body8
6313748862Transcription Initiation- Controls regions of DNA - Promoter closely controls DNA sequence and binding of RNA polymerase/ transcription factors (base rate) - Enhancer distantly controls DNA sequences and binds to activator proteins (high rate)9
6313748863Post Transcriptional Control- Alternative RNA splicing - Variable processing of exons creates a family of proteins10
6313748864Regulation of mRNA Degradation- Life span of mRNA determines amount of protein synthesis11
6313748865RNA Interference siRNA- Short segments of RNA - Binds to mRNA - Creates sections of double stranded mRNA - Death tag for mRNA (Degration) - Causes gene silencing - Post transcriptional control - Turns off genes because no proteins are produced12
6313748866Control of Translation- Blocks initiation of translation stage - Regulatory protein attaches to the 5 end of mRNA - Prevents the attachment of ribosomal subunits and initiator tRNA - Blocks translation of mRNA protein13
6313748869Proteasome- Protein Degrading Machine - Waste disposer - Breaks down any proteins into 7-9 amino acid fragments - Cellular recycling14
6313748870A mutation that makes the regulatory gene of an inducible operon nonfunctional would result in- continuous transcription of the operon's genes.15
6313748871A mutation that inactivates the regulator gene of a repressible operon in an E. coli cell would result in- continuous transcription of the structural gene controlled by that regulator.16

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