DAT Biological diversity pt 4 cheat sheet Flashcards
are viruses living or nonliving
non living
2 examples of viruses
bacteriophage and retroviruses
RNA viruses that use reverse transcriptase to
create double stranded DNA transcripts from single stranded
RNA genome
retrovirus
3 components of virus
nucleic acid, capsid, viral envelope
Viral genome integrated into bacterial genome
prophage
Viral genome integrated into eukaryotic genome
provirus
Protein coat enclosing and protecting nucleic acid
capsid
Outer membrane layer of virus
viral envelope
composed of host cell
membranes, other membrane proteins, and viral
glycoproteins
viral envelope
Enveloped viruses are typically found in…
animals
viruses and bacteria both have…
nucleic acids
Viruses that infect bacterial cells
bacteriophage
what extra structures does a bacteriophage have
sheath, tail fibers
Helps eject viral DNA into host
sheath
Help with recognition and
attachment
tail fibers
Disruption of host genes involved in cell replication by injection/integration of viral
genome can lead to…
cancer cell development
Rapid onset of symptoms and virion replication
acute
how quickly is acute viral infections gone
brief, resolved in days
Initial period of high viral load -> reduced to low once immune system
controls infection -> lasts several years to a lifetime
chronic
Intermittent phases of high and low viral loads after initial acute à lasts
years to a lifetime
latent
Seems dormant after initial viral load but progresses (viral
replication) years later
slow progressing
prevent phages from identifying bacterial surface proteins
cell surface mutation
cut at specific recognized
sequences to prevent replication
restriction enzymes
Internal defense of bacteria that recognizes and cuts out viral
genomes à Used in biotechnology for genome editing
CRISPR Cas system
In large
population (viral outbreak)
epidemic
Global
impact (viral outbreak)
pandemic
Weakened agents that
mimic disease-causing
organism to stimulate
immune system
vaccine
Viruses mix genes to increase
host ranges; difficult to treat
Antigenic shift:
Minor changes in viruses
allow for infection of same host species
antigenic drift
Infectious misfolded
proteins that cause other
proteins to misfold into the prion form
prion
Single stranded
RNA molecules
that infect
plants
viroids
Bacteriophage infects and injects genome into host cell,
then transcribes it into viral particles that are assembled
into new viruses à host cell bursts and is destroyed
while virus replicates and attacks other cells
lytic cycle
Active process where phage replicates in host cell
lytic cycle
Passive process à Bacteriophage integrates into host
genome without actively creating new viral particles.
Every time host cell replicates, viral genome replicated
as well
lysogenic cycle
Viral genome may later be triggered to enter lytic cycle
to produce new viral particles
lysogenic cycle
viral life cycle steps
- attachment
- entry
- uncoating
- synthesis/replication
- self assembly
- release
between host cell and specific viral surface
proteins
attachment
set of species a virus can infect
host ranges
Depending on virus type and host cell à
bacteriophage inject genome into bacterial host cell using
protein tail; enveloped viruses will fuse their viral envelopes
with host membrane, and other viruses are taken in via
endocytosis
entry
how does bacteriophage inject genome
protein tail
Once inside host, viral genome is exposed via
breakdown of viral capsid
uncoating
how is viral genome exposed
breakdown of viral capsid
Virus replicates its genome and viral
proteins à requires host’s nucleotides, enzymes, and
ribosomes
synthesis/ replication
what does synthesis/replication require
hosts nucleotides, enzymes and ribosomes
Viral components spontaneously assemble
into new complete viral particles called virions
self assembly
Where viral shedding allows newly replicated viral
particles to leave host
release
