Viruses Flashcards
Why do viruses have to infect host cells?
they can’t reproduce/divide by themselves
Are viruses alive?
no
Which two ways can viruses multiply?
the lytic and lysogenic cycle
What happens during the lytic cycle?
The virus attaches to the host cell.
The virus enter the cell and injects its DNA or RNA into the cell
The virus DNA/RNA copies itself, causing new virus proteins to be made using the organelles in the host cell
The DNA/RNA and virus proteins are packaged together to make new viruses
The viruses are then released from the cell, which usually destroys the host cell as it destroys the cell membrane (lysis)
What happens during the lysogenic cycle?
Virus attaches to host cell
Virus enters cell and injects its DNA/RNA into the cell
The virus inserts its DNA into the chromosomes of the host cell
(this is called a provirus)
The provirus replicates with the rest of the DNA every time the host cell divides
The provirus can stay dormant for a long time
At any point, the provirus can enter the lytic cycle
A virus that attaches to bacteria cells is called a bacteriophage
Describe the structure of a virus
small
a fragment of genetic material inside a protective protein coat (capsid)
What is the outside of a virus called?
a capsid
What is a capsid?
a protective protein coat around the outside of a virus
