Chapter 13 Flashcards
viruses
what are viruses
minuscule , acellular, infectious agents
are viruses dna or rna
can be either
what do viruses infect
animals, humans, plants, bacteria, and fungi
are viruses sitll common in the industrialized world?
yes
do viruses perform metabolism
no
do viruses have independent replication
no
are viruses alive
no
what do viruses hijack
the hosts cells metabolic pathways
what common cell features do viruses lack
cytoplasmic membrane, cytosol, and organelles
what is extracellular mean
outside the host cell
what does intracellular mean
inside the host cell
viron def
a protein coat (capsid) surrounding nucleic acid
what is a virus called when its outside the cell
a viron
what do some virons have
some have phosholipid envelope
what is the outermost layer of a viron for
for protection, and recognition sites
what happens when the virus is inside the host cell
capsid is removed and the virus exists as nucleic acid
genetic material of viruses is what . 3 points
may be DNA or RNA
can be single or double stranded
much smaller than the genome of cells
what do most viruses infect
only particular host cells
what are viral surface proteins attacted to
the host surface
how can we classify viruses
by nuclei acid type, shape, size, or presence of envelope
caspids def
protein coat
what do caspids protect
protect viral nucleic acid
what do caspids attach to
to host cells
helical shape
oval ish rectangle
polyhedral shape
sphere with pokes coming out of it
spherical shape
a sphere
complex shape
like a bacteriophage
the viral envelope is a portion of what
evelope is a portion of host membrane
where is the viral envelope acquired from
from host during viral release
what is the viral envelope composed of
phospholipid bilayer and proteins
bacteriophage is what
a virus that infects bacteria
what are the 2 main cycles of bacteriophages
lytic and lysogenic
lytic cycle isssss
when they quickly generate more virions
and lyse the host cell (burst it )
lysogenic cycle isssss
when the viral genome integrates into host genome
and it replicates within host for many generations
what are the 5 stages of the lytic cycle
attachment to host cell
entry and cuts up host DNA
synthesis and hijack trans. transl
assembly of all the virion parts
release out of the cell
what does the lytic cycle hijack
they hijack host processes to produce new virions
what phages perform lytic replication
virulent phages
what phages perform lysogenic replication
temperate
what does prophage mean
that phage DNA integrates into host genome
what are the steps of the lysogenic cycle
phage attaches to the cell
phage DNA enters the cell
phage DNA integrates into the host DNA
Last, the host cell replicates and passes down the phage genome to future generations
whats beneficial of the lysogenic cycle
the virus can spread in the host population over time without killing the host cells
could prophage enter the lytic cycle?
yes if specific stimuli trigger it to , like UV or chemicals
what do the lytic and lysogenic cylce both do
accomplish the viruss goal of making copies of viral genome
animal virus replication info about attachment
glycoprotein spikes or other molecules mediate attachment
animal virus replication info about entry
it enters and uncoats
DNA viruses in animal cells during synthesis
they oftern enter the nucleus where there are DNA polymerase and other tools to replicate DNA are
RNA viruses in animal cells during synthesis
they often replicate in the cytoplasm where there are RNA polymerase, ribosomes, and other tools to replicate rna are
special info about rna viruses replications
they need special enzymes
retroviruses is what
a type of rna virus
What do retroviruses do
use viral reverse transcription enzyem to synthesize DNA from rna
what is the retrovirus different from
different from RNA dependent rna polymerase
reverse transcriptase info
rna to dna
what do retroviruses integrate
the reverse transcribed dna into the host genome
latency def
when animal viruses remain dormant in host cells
rna dependent rna polymerase info
rna to rna (copy of)
what does latency incorporate
viral dna into host dna
ex of latency
chicken pox coming back as shingles
What do proto oncogenes promote
cell growth and division
what can unctrolled activation of proto oncogenes lead to
cancer
how much % might viruses cause of human cancers
20 to 25
with no virus and a repressor what happens
no cancer
with one virus and a repressor what happens
no cancer
with a double hit of viruses and no repressor what happens
yes cancer
