2p- Parasitic life cycles Flashcards
How many hosts do parasites require to complete their life cycle?
Some require only one but many require more than one host
What is the definitive host?
The organism on or in which the parasite reaches sexual maturity
As well as a definitive hos, what may also be required for a parasite to complete its life cycle?
Intermediate hosts
What does a vector do?
Plays an active role in the transmission of the parasite and may also be a host
What are viruses?
Parasites that can only replicate inside a host cell
What do viruses contain?
Genetic material in the form of DNA or RNA, packaged in a protective protein coat
What are some viruses surrounded by?
A phospholipid membrane derived from host cell materials
What does the outer surface of a virus contain?
Antigens that a host cell may or may not be able to detect as foreign
What are the 4 stages of a viral life cycle?
- infection of host cell with genetic material
- host cell enzymes replicate viral genome
- transcription of viral genes and translation of viral proteins
- assembly and release of new viral particles
What do Rna retroviruses use to form DNA?
The enzyme- reverse transcriptase, this is then inserted into the genome of the host cell
What can be expressed to form new viral particle?
Viral genes
