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Semester 1, Day 6 Viruses
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Agenda Study Turn in Homework Quiz on Enzymes, DNA, RNA, Proteins, & Transcription/Translation Lecture Reading/Work Time
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Study Purpose of enzymes Enzymes are a type of… Lock & Key Model Enzyme steps (label diagram) Characteristics of enzymes DNA (label diagram) Why does DNA have a twisted shape? (think hydrophilic/hydrophobic parts) RNA characteristics mRNA, rRNA, tRNA DNA, RNA, and protein functions Steps of transcription Steps of translation
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Turn in Homework Questions: 11.1 #1-6, 11.2 #1-6
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Quiz Enzymes DNA, RNA, Proteins Transcription & Translation Question #4
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Viruses What is considered living? Recall: Cells are the basic unit of life All cells have: A plasma membrane Cytoplasm Ribosomes DNA Bacteria, Archaea, Animals, Plants, Fungi, & Protists are ALL living! Made of one or more cells Grows and develops Reproduces Responds to environment Requires energy Viruses are not considered living: No organelles (not cells) Don’t require energy Can’t grow or replicate on their own Some characteristics of life Much simpler!
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Viruses Virus Parts: Capsid (coat of proteins) Genetic Material (DNA or RNA, never both) Must Haves Capsid Genetic Material Fiber Adenovirus Envelope Spike Influenza Virus Capsid Tail Tail Fiber Bacteriophage Genetic Material Tobacco Mosaic Virus Capsid Image Source: www.virology.wisc.edu
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Viruses Viral Infection: to replicate, virus must enter a host cell 2 Cycles: Lytic & Lysogenic Lytic: viruses copied using host cell. New viruses then leave by bursting, “lysing”, the host cell Lysogenic: virus is inactive until stress activates the provirus genes and starts the lytic cycle. Lytic Cycle Lysogenic Cycle Attachment Entry Replication Assembly Release Provirus Formation Bacteria Cell Division Separation
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Viruses Lytic Cycle: Attachment: Virus attaches to bacterial cell using specific receptors on host cell. The receptors are why viruses aren’t transmitted between species. Entry: Virus injects its DNA into the bacterial cell Replication: The virus uses the bacteria’s machinery to replicate the parts of the virus Assembly: New viruses are assembled from parts Release: New viruses burst through the host cell, killing it Lysogenic Cycle: Provirus Formation: Viral DNA becomes part of the bacterial chromosome Cell Division: The bacteria cell divides, which replicates the provirus, too. Separation: Provirus leaves the bacterial chromosome.
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Reading/Work Time Cornell Notes: Section 18.1, 18.2 Questions: Section Assessment 18.1: #1-6 Section Assessment 18.2: #1-6 Chapter 18 Assessment: #1-17, 19-26 Beginning 30 minutes = Silent independent work time
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Review Review Questions
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