MicroBiology- Viruses Flashcards Preview

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Flashcards in MicroBiology- Viruses Deck (4)
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1

VIRUS

- Viruses aren’t living organisms→ they are collections of genetic material (RNA or DNA) enclosed in a protein coat (capsid)
- Can’t reproduce like a living cell→ instead invade host cell and hijack reproductive mechanisms

2

VIRUS STRUCTURE

- Genetic material in protein shell
- Some viruses have outer layer formed from plasma membrane of host cell
- In some viruses→ some enzymes they need for reproduction

3

VIRUS REPRODUCTION

- Virus attaches to specific host cell surface
- Virus penetrates host cell→ becomes ‘uncoated” → its genes are released
- Multiple copies of the viral genes are made
- Viral proteins are made using info in viral genes BUT using host cell ribosomes and amino acids
- Multiple copies of the virus are assembled
- New viruses leave the cell to infect other cells→ as they do so they lyse the cell or weaken it so it dies

4

VIRAL INFECTIONS

- Most viral infections are acute; within short periods after infection the immune system eradicates virus
- Some viral infections (e.g. Hepatitis C) are chronic: body never completely removes virus
- Some show latency; prolonged infection period (with viruses slowly reproducing) during which infected person shows no signs or symptoms