Exam II Microbiology: Chapter 5 Flashcards
A fully formed virus that is able to establish an infection in a host cell
Virion
Protein shell that surrounds the nucleic acid
Capsid
The capsid together with the nucleic acid
Nucleocapsid
Naked viruses consist only of a ___________; no outer membrane
Nucleocapsid
Can be found on naked or enveloped viruses
Spikes
External covering of a nucleocapsid, usually a modified piece of the host’s cell membrane
• Viruses take a piece of the cell membrane when they are released from a host cell.
Envelope
- Single-stranded (ss)
- Double-stranded (ds)
- Linear
- Circular
DNA Viruses
• Double-stranded, but more often single-stranded
must be copied into mRNA before translation can occur
RNA Viruses
Ready for immediate translation (mRNA)
Positive single stranded RNA
Must be copied into mRNA before translation can occur
Negative single stranded RNA
+ ssRNA = ___________
mRNA
Carry their own enzymes to create DNA out of RNA
Retroviruses
What are the two different types of capsids?
- Helical
2. Icosahedral
What capsid structure is rod-shaped?
Helical
What capsid structure is geometric in shape and made of 20 triangular pieces?
Icosahedral
What capsid structure has an icosahedral head and many accessory structures that only infects bacteria and is designed to be able to punch through cell walls?
Complex
What are the general phases of the animal viral replication CYCLE called?
The Lytic Cycle
Viruses cannot bind to cells that lack _________ _________ ___________ ?
compatible virus receptors
The entry of the virus through the plasma membrane (and for some cells the cell wall) and movement into the host cell is what part of the lytic cycle?
Penetration
A condition in which the host chromosome carries viral DNA:
Lysogeny
A virus can invade its host cell only through making an exact fit with a specific host molecule (receptor) on the surface of the cell is what part of the lytic cycle?
Absorption (Attachment)
The release of nucleic acid through break down of capsid into cytoplasm of host cells is what part of the lytic cycle?
Uncoating
Replication and protein production is what part of the lytic cycle?
Synthesis
Which virus enters the host cell’s nucleus and replicates?
DNA viruses
Messenger RNA’s for the viral proteins are made in the nucleus in which virus?
DNA viruses