Chapter 17 Flashcards
virus
infectious particle consisting of little more than genes packaged into a protein coat
capsid
protein shell that encloses the viral genome
capsids are built from protein sub units called?
capsomeres
viral envelopes are derived from?
host cells membrane and contain a combo of viral and host cells molecules
bacteriophages
viruses that infect bacteria
viruses are ___ because they can___.
obligate intracellular parasites, replicate only within a host cell
host range
limited number of host species that it can infect
viral infections of multicellular eukaryotes are limited to?
particular tissues
lytic cycle
phage replicative cycle that culminates in the death of host cell.
lytic cell produces ___ and lyses the ___
new phages, the host cell wall
virulent phage
phage that reproduces only by lytic cycle
lysogenic cell
replicates the phage genome without destroying the host
temperate phages
phages that use both lytic and lysogenic cycles
The viral DNA molecule is incorporated into the ____ during lysogenic cycle.
host cell’s chromosome
prophage
integrated viral DNA
Every time a host divides it?
copies the phage DNA and passes the copies to daughter cells
An environmental signal can trigger the viruses genes to ?
exit the bacterial chromosome and switch to lytic mode
Phage DNA is often identified as __ and cut up by ___
foreign, restriction enzymes
Retroviruses use __ to copy their RNA genome into DNA
reverse transcriptase
Human immunodeficiency virus
retrovirus that causes acquired immunodeficiency syndrome
Provirus
viral DNA that is integrated into the host genome
A provirus is a permanent?
resident of the host cell
RNA molecules function both as?
mRNA for synthesis of viral proteins and genomes for new viruses.
Mobile genetic elements
plasmids, transposons, and viruses
