Viruses II Flashcards
Patterns of viral infection * 3 part *
Acute infection: symptoms get worse in a
short period then elimination of virus from immune system
Long term: chronic infections
Asymptomatic infection: viruses force cells to produce virions without causing symptoms
Viral infections steps * 5 part*
- Attachment
Phage attaches to host surface - Entry Viral DNA enters the host cell
- Replication
- Phage DNA replicates
- phage proteins are made - Assembly
- New phage particles are assembled - Release
- Cell lyses releasing the newly made phages
Impact of Viral Infection * 1 part*
Viral replication can produce dramatic biochemical & structural changes in the host cell, can cause cell damage
Cytopathic effects * 1 part :)*
Can change cell function/ destroy cells
Symptoms of viral diseases * 2 parts *
- Results from the immune responses to the virus
- Attempt to control and eliminate virus from body & from cell damage cause by the virus cell
Infected cells die through * 3 parts*
- Lysis: bursting, the virus builds up inside the host cell.
The host cell bursts open, releasing all the new viruses at once.
The host cell dies immediately. - Apoptosis: programmed death “ suicide” releasing all progeny virions at once.
- Budding:
Virions leave the cell individually
wrapping itself in part of the cell membrane.
Host cell doesn’t die right away, but rather damage over time and might stop working properly.
Sometimes, the host cell stays alive and keeps making more viruses.
Bacteriophage Lysogenic cycle * 4 steps*
- Phage infects a cell
- Phage DNA enters the host genome & becomes a prophage (part of host genome)
- Cell Divides & prophage DNA is passed on to the new daughter cells but stays inactive
- Under stress
the phage DNA is active and cuts out from the bacterial chromosome and enters the lytic cycle ( creating new viruses)
Bacteriophage LYTIC cycle * 4 steps*
- Phage infects a cell
- The phage DNA circularizes, remaining separate from the host DNA
- Phage DNA replicates & phage proteins are made, New phage particles are assembled
4.The cell lyses releasing phage
What is the host genome * 3 part*
- The host genome refers to the entire genetic material of the host.
- Plants & animals have linear genome
- Some plants are circular
bacteria have a circular genome
Difference between lysis and lyses * 2 part*
lysis is what is happening the bursting of cells
lyses describes what’s causing the bursting
Difference between lysogenetic and lytic cycle * 2 part*
- Lysogenic = virus DNA enter into the host DNA and stays dormant/ inactive for a while.
- Lytic = virus actively replicates inside the host cell, eventually causing the cell to burst.
Latent viruses * 3 part*
EX: Shingles
- can exist in the tissue for long periods without producing new virions
- leave latency when the host is under stress to cause intermittent symptoms
oncogenic viruses * 3 part*
- Causes cancer by messing with how the host cell normally controls its growth.
- The virus either: Stimulates new growth by introducing genes that promote it, or
Interferes with genes that normally stop the cell from growing too much. - Virus disrupts the normal control of the cell, leading to uncontrolled growth
Viral infections in plants * 3 part *
- Damage to the plants cell must happen to allow the virus to enter a new host
- Damage causes: Weather, insects, animals, fire or human activities
- Plants offsprings may inherit viral diseases
Viral transmission in plants 3 part
- Contact with infected plants, living organisms & nematodes & through pollen
- Plant to plant virus transfer
is horizontal transmission - Vertical transmission: inherited from parents
up & down
symptoms of infection in plants * 5 part*
- HYPERplasia: Galls (Tumors)
- HYPOplasia - Thinned yellow splotches on leaves
- Cell Necrosis - Dead, blackened stems leaves or fruit
- Abnormal growth: The patterns malformed stems, leaves or fruit
- Discoloration - Yellow, red or black lines, or rings in stems, leaves or fruits
what are vaccines * 5 part*
building Immunity
Can be live, killed or molecular
killed & subunit viruses cannot cause disease
live vaccines: weaker state of viruses
growing vaccinas under abnormal conditions
Anti Viral drugs * 4 chunks*
Inhibit the virus by blocking the actions of one or more of its proteins
targeted proteins encode d by viral genes these molecules are not present in a heating host
Viral growth is inhibited without damaging the host
control & reduce symptoms
Anti - HIV Drugs
- Anti-HIV drugs can stop the fusion of HIV envelope with cell membrane.
Anti-HIV drugs blocks HIV from reverse transcribing into DNA that does this conversion
- Anti- HIV drugs stop HIV from integrating into host cell by blocking the enzyme (Integrase) that integrates the viral DNA.
Anti-HIV drugs block the enzyme (Protease) that helps process the viral proteins into the right shape preventing the virus from making new virions
What are prions
Infectious agents made only of protein
NO DNA or RNA like other viruses or bacteria.
Causes harm by changing the shape of normal proteins in the body, making them misfold.
Once the prions change the shape of proteins, they accumulate in tissues, which can lead to serious damage to the brain.
Virions
Virus particles that can leave the host cell in two ways
Lysis & Budding
May leave host cells in groups
