Viruses Flashcards
What are viruses
Viruses are parasites that can only replicate inside a host cell.
What genetic material doo viruses contain?
Viruses contain genetic material in the form of DNA or RNA, packed in a protective coat
What are some viruses surrounded by?
Some viruses are surrounded by a phospholipid membrane derived from host cell materials
How do viruses go undetected by antibodies?
The outer surface of a virus contains antigens that a host cell may or may not be able to detect as foreign
Viral life cycle stages -1st stage
Virus approaches a cell
2nd stage of viral lifecycle
after approach
Virus attaches to cell
3rd stage of viral life cycle
after attachment
Viruses genetic material is injected into the host cell
4th stage of viral life cycle
after penetration
Viral genes interrupts the host cells metabolism and uses host cell enzymes to replicate the viral genome
5th stage of viral life cycle
after DNA replication
Viral proteins are made using the host cells machinery and resources. Transcription of viral genes and translation of viral protein occurs
6th stage of viral life cycle
after protein synthesis
New viruses are assembled as the new DNA enters the new protein coats
7th stage of viral life cycle
New viral particles leave the host cell to infect new hosts
What are viruses that carry RNA called?
Retroviruses
What does RNA retroviruses do ?
Us the enzyme reverse transcriptase to form DNA
Function of RNA retroviruses
On injecting their RNA into a host cell, they also inject reverse transcriptase. This brings about the synthesis of DNA from single stranded RNA. The newly formed DNA is then inserted into the genome of the host cells.
