Copy of Bio 1 Lec 9 - Lecture notes 9 PDF

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Lecture 9 9/17/18 Viruses I. Viruses A. Not _______ B. __________ intracellular parasite 1. Needs host to survive and reproduce; causes _____ C. Every type of virus affects specific unicellular species or cell type 1. Virus enter host cell and “hijack” host cell machinery to reproduce and _______ a) Injects DNA into _____ b) Viral genes are ________,___________, and _________ II. Virtually every system, tissue, and cell can be infected A. ___________- causes disease B. ____________- coexist III. Cause devastating human epidemics A. Spanish flu (50-100 million people) B. HIV (34.5 million people world wide) C. H1N1- same strain as spanish flu D. Ebola IV. Very small A. Pack a lot of viruses in a small space 1. Measure size in __________s of a meter V. Consists of 2 parts A. Virus particle- _______ 1. Contains DNA and RNA 2. Protein coat that surrounds _________ __________ a) Protects DNA and RNA when in particle form VI. Envelope A. _______ _________ B. Offers protection C. Has membrane proteins that works as recognition sites D. Around capsids VII. Wide variety of genomes A. Can be DNA and RNA B. Linear, circular, Long , short C. Single stranded or double stranded VIII. Can infect in two ways A. Lytic cycle 1. Next generation of viruses _____ host cell B. Lysogenic (latency)

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1. Produces state of __________ 2. Doesn’t only put DNA but incorporates viral DNA into the _____ genome a) Trigger that causes virus to make proteins and ____ out of the cell How does a virus get into a cell A. Virus binds into molecule on host _____ ___________ 1. Protein binds to carb 2. Uncoded or __________ inside a) After break down of host cell membrane virus infects Virus have own genetic material A. Needs __________ and _______ B. Virus provides ________, host cell provides __________ Some viruses make long polypeptide chains that need to be __________ A. _________ cleaves the strand B. Protease ________ used to stop virus C. In HIV Viruses need to make DNA and RNA A. Depend on host cell for ___________ B. Need DNA ___________ from host C. In RNA virus- uses viral RNA polymerase called RNA replicase 1. Synthesizes RNA from RNA ________ D. _________ sense RNA is mRNA E. _________ sense RNA needs to be transcribed to positive sense and become mRNA then it can go on and translate proteins Retroviruses A. RNA is transcribed into DNA by _________ transcription Enveloped viruses A. Virus gets an envelope by _________ from host cell 1. Bud off and make new viruses B. Made up of _______ and ___________ Non enveloped viruses burst out of the cell Case Study: HIV A. RNA retrovirus B. Target cells of immune system (T helper cells) 1. T Helper cells stimulate Beta cells and Killer T cells 2. Overtime people cannot fight off other infections due to damaged __________ ________ a) Other complications ex/ pneumonia C. Transmitted by ______ _______ 1. Blood 2. Sex 3. Mother to child

D. Enveloped virus 1. Reverse transcriptase and integrase a) Puts with cell along with DNA b) DNA _________ 2. Start with RNA template which makes____________ RNA a) Removes RNA and reverse transcriptase synthesizes cDNA from RNA b) Then it _________ double stranded DNA from cDNA 3. Integrase a) Occurs inside nucleus b) After reverse transcriptase makes DNA it inserts viral DNA into genome by cutting E. Life Cycle 1. Proteins on outside bind with host cell ________ 2. HIV fuses without envelope with its genome 3. DNA is __________ with host genome and sits a) Makes viral DNA and protein _________ and exits F. AIDS 1. Viral infection can go for years before symptoms are shown 2. Immune system initially fights off virus 3. HIV attacks body, immune system responds which keeps HIV stable a) HIV is still latent in cells b) Over time helper T cells diminish leaving HIV cells to rise G. Vaccine 1. No vaccine since it ________ too quickly 2. Antiretroviral therapy a) ___________ reverse transcriptase b) Protease inhibitor leaves HIV in long polypeptide unable to make viral proteins...