MIDTERM BIOC20 EXAM WITH ANSWERS

MIDTERM BIOC20 EXAM WITH |\ |\ |\ |\




ANSWERS

Virion consists of - CORRECT ANSWERS ✔✔-Nucleic acid
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genome
-protective protein coat |\ |\




-Some contain a lipid envelope
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Virion capsid - CORRECT ANSWERS ✔✔Protective protein
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coat


Nature of Viruses - CORRECT ANSWERS ✔✔Obligate
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intracellular parasites (only replicate in living cell) |\ |\ |\ |\ |\ |\




Viruses lack - CORRECT ANSWERS ✔✔Essential functions
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-synthesis of basic biological building blocks (nucleotides,
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amino acids, CHO's, lipids)
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-generation of ATP |\ |\




-protein synthesis (ribosomes, tRNAs)
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Uncoating - CORRECT ANSWERS ✔✔First step, virus
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particles break down and release genomes inside the cell
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,-released from protective protein shell |\ |\ |\ |\




Once virus uncoats - CORRECT ANSWERS ✔✔Genome can
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be used as a template for mRNA synthesis - produce
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proteins


Newly made viral proteins - CORRECT ANSWERS ✔✔Work
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together to replicate genome, encapsulate the new
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genomes to form progeny virions |\ |\ |\ |\




Virus morphology - CORRECT ANSWERS ✔✔Distinct,
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genome sizes, and particle sizes |\ |\ |\ |\




-smallest 20 nm in diameter, coding few as 2 proteins
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-largest 500nm in diameter, coding > 1200 proteins
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Virus genomes can be - CORRECT ANSWERS ✔✔-RNA or
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DNA, not both |\ |\




-single or double stranded
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-circular or linear |\ |\




Problem with RNA genome - CORRECT ANSWERS ✔✔-no
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RNA polymerase - replication problem
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-difficulty making RNA transcript |\ |\ |\

,Viruses can infect - CORRECT ANSWERS ✔✔All forms of
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life, animals, plants, insects, bacteria, algae,, fungi
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Most abundant form of life - CORRECT ANSWERS
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✔✔Viruses, 10 fold excess of virus compared to bacteria |\ |\ |\ |\ |\ |\ |\ |\ |\



in earth oceans
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Mass = 1 million blue whales
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Length - 200 million light years
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Study of viruses led to - CORRECT ANSWERS
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✔✔Identification of promoters for eukaryotic RNA |\ |\ |\ |\ |\ |\



polymerase
Enzymes involved in cellular DNA replication |\ |\ |\ |\ |\




RNA splicing from studying viral mRNAs in eukaryotic
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cells
Isolation of numerous cellular oncogenes and the
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understanding that cancer is caused by their mutation or |\ |\ |\ |\ |\ |\ |\ |\ |\



unregulated expression |\




First virus discovered - CORRECT ANSWERS ✔✔TMV
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First virus discovered by - CORRECT ANSWERS
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✔✔Distinguished by filtration |\ |\ |\




Russian scientist Dimitri Ivanovski
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, Dutch scientist Martinus Beijerinck (first name for virus =
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contagious virus fluidium) |\ |\




TMV - CORRECT ANSWERS ✔✔Tobacco mosaic disease
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killing tobacco plants
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Found by grounding up infected leaves trying to filter
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bacteria, passed through porcelain filter was infecting
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leaves


Discovery about viruses in mid 1930s - CORRECT
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ANSWERS ✔✔Highly purified TMV could form crystals
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-challenged conventional notions about genes and nature
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of living organisms
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Are virsuses alive? - CORRECT ANSWERS ✔✔Not living
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entities, biochemical processes - only living period inside
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host


1915-1917 scientist in England and France discovered
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bacteria - CORRECT ANSWERS ✔✔Could be listed by
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filterable agents |\




Study of bacteriophages helped establish the field of
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molecular biology by - CORRECT ANSWERS ✔✔Mapping
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phage genes |\