Viruses Flashcards
(30 cards)
What is a virus?
An infectious particle consisting of genes packaged in a protein coat.
What types of organisms can viruses infect?
A whole range including: plants, animals and bacteria.
Can viruses reproduce?
No.
What does the infectious particle consist of?
Nucleic acid and protein.
What size do viruses range from?
20nm - 1,000nm
What is the virus built up of?
Capsids, Envelopes and Genomes.
What does Bacteriophage T4 infect?
Bacteria
What is a capsid made of?
Capsomeres.
Genomes in viruses can consist of either?
Double or Single stranded DNA or RNA.
How many genes can be in the genome of a virus?
3-1,000s.
A parasite cannot complete life cycle without?
Suitable Host.
Measles can only infect?
Humans.
What do viruses use to create protein?
Host mechanism.
What are phages?
Viruses that infect bacteria.
What are the two methods a bacteria can replicate in a bacterial phage?
Lytic Cycle or Lysogenic cycle.
In the lytic cycle, when host recognises that the bacterial phage is foreign, what happens?
The phage DNA is cut up.
What is special about the Lysogenic Cycle?
It doesn’t destroy the host.
Phages that use both cycles are called?
Temperate phages.
In the lysogenic cycle, when the host divides, what happens to the phage?
The page DNA also get replicated and divides with the host.
What can the lytic cycle be increased by?
Radiation or chemicals in the environment.
How many categories of animal viruses are there?
6.
What do retroviruses use to copy RNA genome into DNA?
Reverse transcriptase.
What is an example of a retrovirus?
HIV is a retrovirus that causes AIDS.
In the replicative cycle, where are viral envelopes derived from?
The host’s plasma membrane OR the host’s nuclear envelope.
