Term
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Definition
Are sub cellular: Contain no cellular components (except for nucleic acid).
Obligate intracellular parasites: Can only replicate in a cell (using the cell's machinery). |
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Term
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Definition
Helical: Hollow stalk.
Icosahedral: 20-sided (will appear spherical in small virus).
Spherical
Complex Form: Made of several different shapes. |
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Term
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Definition
| Protein shell of a virus. Made of of capsomere subunits. |
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Term
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Definition
| Made up of capsid and nucleic acid (collectively called nucleocapsid). Some viruses contain proteins and some animal viruses have a membrane called an envelope around them. |
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Term
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Definition
| Viruses that infect bacteria. Only there nucleic acid enters the bacteria. |
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Term
| Viral Entry Into Host Cell |
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Definition
Molecules on viral surface (called spikes or peplomers) bind to molecules on a host cell (these molecules determine host specificity).
Viral envelope fuses with cell membrane and virus enters, or virus is taken into cell via pinocytosis. |
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Term
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Definition
DNA Virus: Uses host enzymes for replication, transcription, and translation.
RNA Virus: Uses viral enzymes for replication and transcription but host enzymes for translation. |
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Term
| Phage Replication (Lytic) |
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Definition
- Phage attaches to bacteria and the sheath of the tail contracts, punching a hole in the bacterial membrane.
- The phage then inserts its DNA into the bacteria and releases enzymes that hydrolyzes the bacterial DNA.
- Bacterial machinery replicates phage.
- Phage DNA directs the creation of lysosomes which cause the cell wall to breakdown and burst, releasing phage. |
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Term
| Phage Replication (Lysogenic) |
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Definition
| Phage DNA can integrate itself into the bacterial DNA and remain dormant for some time before entering a lytic phase. The phage DNA will get replicated many times by bacterial division. |
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Term
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Definition
| Enveloped animal viruses are slowly created by animal cells and periodically released via budding. |
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Term
| Replication of RNA Viruses |
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Definition
| Viral enzyme "reverse transcriptase" transcribes viral RNA to dsDNA. dsDNA is incorporated into the hosts chromosomes (provirus) and can remain dormant (latent). When provirus becomes active, it is transcribed to RNA and can act as both genome and mRNA for the translation of viral proteins. |
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Term
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Definition
| Previously uknown infection that is appearing (HIV). |
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Term
| Virus Association With Cancer |
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Definition
| Some viruses interfere with proto-oncogenes (genes that are involved in controlling the cell cycle). THis can lead to uncontrolled cell growth and tumors. |
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Term
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Definition
| Small circular pieces of DNA that can infect plants and interfere with their growth control system. |
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Term
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Definition
| Misfolded proteins that cause spongiform encephalopathy (mad cow, chronic wasting, scrapie, kuru). |
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