Chapter 13 - ii. Lysogenic cycle 1. Integrates its nucleic...

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Chapter 13: Genetics of Viruses and Prokaryotes I. Why study bacteria and viruses? a. Small genomes b. Cause us disease so it’s good to understand them c. Reproduce quickly d. Usually haploid II. Viral Genetics a. Not considered living i. Acellular b. No transport of nutrients/waste c. Nucleis acid (core)/protein capsid (coat) i. Capsid could be different shapes d. Parasites i. Can infect all life 1. Bacteriophage (phage) – infects bacteria III. Phage Life Cycle a. Binds to receptor on bacteria b. Injects nucleic acid into bacteria c. Then: i. Lytic cycle (virulent phage – always kills its host) 1. Lysis so that cell bursts and releases virions 2. RNA polymerase recognizes phage’s nucleis acids and starts expressing its genes (early stage genes) 3. Makes proteins that chop up host’s bacterial DNA a. Hijacks the cell b. Stops bacterium from doing what it wants 4. Starts making copies of viruses nucleic acids and proteins needed to make the protein coat (late stage) 5. The cell lyses and all the virions are released
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Unformatted text preview: ii. Lysogenic cycle 1. Integrates its nucleic acid with bacterial DNA a. By recombination 2. Now every time bacteria divides, the virus DNA gets copied a. Prophage hides in bacterial chromosome b. Lysogenic bacteria 3. If environment for bacteria is not favorable, the phage DNA pops out (activates) and starts the lytic cycle IV.Gene Regulation in Prokaryotes a. Inducible systems: Substrate of a metabolic pathway (inducer) interacts with a regulatory protein (repressor)repressor cannot bind to operator allowing transcription. Catabolic pathways i. Inducible systems control catabolic pathways (turned on when substrate is present) b. Repressible system: Product of a metabolic pathway (corepressor) interacts with a regulatory protein (repressor) allowing it to bind to operator, blocking transcription. Anabolic pathways i. Repressible systems control anabolic pathways (turned on when product is not present)....
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This note was uploaded on 01/27/2011 for the course BIOSC 0160 taught by Professor Bledsoe during the Spring '08 term at Pittsburgh.

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Chapter 13 - ii. Lysogenic cycle 1. Integrates its nucleic...

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