Life Cycles And Viruses Flashcards
what are the six common parasite groups
protists, platyhelminthes, bacteria, anthropods, viruses and Nematoda
describe a protist and give an example of one
small unicellular organism, plasmodium
give an example of a platyhelminthes
schistosoma, tape worms
what is tb
a bacteria
in what host does the parasite reach sexual maturity
definitive host
describe the life cycle of a plasmodium
protist that causes malaria, definitive host is mosquito, intermediate host is human, vector is mosquito
describe the life cycle of schistosomiasis
cause by platyhelminthes, definitive host is human, intermediate host is water snail, transmitted by water borne stages
how are ectoparasites usually transmitted
direct contact
how are body cavities endoparasites usually transmitted
direct contact or consumption of intermediate host
how are endoparasites of body tissues usually transmitted
vectors
what is a virus
an infectious agent that can only replicate inside a host cell
describe the structure
envelope, antigens, nucleic acid, protective protein code
what are antigens
proteins coded by viral genes detected by immune system
give an example of a virus that contains DNA
chickenpox
give an example of a virus that contains rna
influenza
describe the four stages of DNA viral replication
- virus antigens attach to cell surface, 2. virus DNA inserted into the host cell, 3. virus DNA is replicated using host enzymes, 4. viruses genes are transcribed to rna which is translated to make viral proteins coded
what is a retrovirus
contains rna, uses a different reproduction method to form a DNA copy of its genome
describe the steps in retrovirus reproduction
virus antigens attach to host cell surface, virus RNA inserted into host cell, viral enzyme called reverse transcriptase reads viral RNA to form DNA, new virus particles are assembled and burst out of host cell
what is retrotransposons
virus derived mobile DNA elements with ability to copy and paste themselves into hosts genome long after initial attack
