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15 Cards in this Set
- Front
- Back
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What are viruses' genomes made of? book - p 394 notes - p 1 |
Any form of DNA or RNA |
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What is capsid? book - p 394 notes - p 1 |
protein shell enclosing viral genome |
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What is capsid made of? book - p 394 notes - p 1 |
capsomeres = protein subunits |
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What is a viral envelope? book - p 395 notes - p 1 |
-membranous envelope surrounding capsids of some viruses -derived from host cell's membranes (they steal it) |
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What is a phage? book - p 395 notes - p 2 |
virus that infects bacteria, aka bacteriophage |
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Why are viruses not alive? book - p 395 notes - p 1 |
-no cells (just structural and genetic proteins) -obligate intracellular parasites (cannot metabolize or reproduce on own) |
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What is the host range? book - p 395 notes - p 2 |
The types of cells viruses are able to infect |
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What is the viral reproduction cycle? book - p 395, figure 19.4 notes - p 2 |
1) virus enters cell, releasing viral DNA 2) host enzymes replicate genome 3) host enzymes transcribe genome into mRNA, host ribosomes make more capsid proteins out of mRNA 4) genomes and proteins self-assemble into new viruses, lyse cell |
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What is the lytic cycle? book - p 396, figure 19.5 notes - p 2 |
culminates in death of host called lytic because it lyses the cell |
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What type of phage only replicates through the lytic cycle? book - p 397 notes - p 2 |
virulent phage |
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What is the lysogenic cycle? book - p 397 notes - p 2 |
-opposite of lytic cycle -does not result in death of host -is limit to how many times a virus will lay dormant in DNA before killing cell |
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What type of phage reproduces through the lysogenic cycle? book - p 397 notes - p 2 |
temperate phage |
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Can a temperate phage become a virulent phage? notes - p 2 |
Hell yeah! The environment triggers the DNA in the host chromosome to create phages and then will lyse the cell |
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How does the lysogenic cycle work? book - p 397 notes - p 2 |
-DNA hides in cell's chromosome. hiding DNA = prophage -prophage genome is silent until environmentally triggered. cell functions normally -once triggered, produces phages and lyses cell |
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How did viruses evolve? book - p 398 notes - p 2 |
1) cellular origin - viruses are "escaped" genetic material. explains why they are so species-specific 2) co-evolution or virus-first hypothesis - viruses appeared prior to cells and have evolved with host, explains evolutionary arms race |
