Viruses U.1 L.5
viruses don’t have cells
viruses possess some properties of living things, they can move, they reproduce (through a host cell), they contain DNA/RNA
viruses technically aren’t living because they have no cells, they cant live without a host cell, they are dormant without a host cell & they don’t grow
viruses are not a cellular structure
inner core of nucleic acid (DNA/RNA) surrounded by a coat of protein called capsid
extensions on viruses are called antigens (spikes), which allow viruses to identify, attack and enter its host
typically infectious to a specific host dependant on antigen shape (vaccines are based on shape of antigens)
viruses only enter their specific cells
host range : the number of species, tissues or cells that can be specially infected
some viruses can create an envelope (when leaving a host cell and part of the host cells membrane wraps around the virus
structure of virus : head/capsid, DNA
many different structures of viruses
human viral disease examples : poxviruses : smallpox, direct contact and airborne droplets
viruses can be transmitted through direct contact, inhalation
Epidemic : large outbreak of disease in a certain region
Pandemic : outbreak of disease over a huge region sometimes globally
lytic cycle
attach & insert
bacteriaphage attaches and inserts itself into a bacteria (use antigens to ID attached to host, inject DNA)
synthesis
use host organelles to make new viral components ( NOT a cell ), use viral DNA as instructions
assembly
put together components to make virus clones
lysis (release)
new virus burst (lyse) the host cell releasing to infect others
lytic cycle leads to immediate symptoms
lysogenic cycle:
1. still attach and insert
bacteriaphage attaches and inserts itself into a bacteria (use antigens to ID attached to host, inject DNA)
after viral DNA is inserted it combines with host DNA
so that when the host reproduces the viral DNA will also be copied (viral DNA lays dormant until activated : then enters lyctic cycle)
Viruses U.1 L.5
viruses don’t have cells
viruses possess some properties of living things, they can move, they reproduce (through a host cell), they contain DNA/RNA
viruses technically aren’t living because they have no cells, they cant live without a host cell, they are dormant without a host cell & they don’t grow
viruses are not a cellular structure
inner core of nucleic acid (DNA/RNA) surrounded by a coat of protein called capsid
extensions on viruses are called antigens (spikes), which allow viruses to identify, attack and enter its host
typically infectious to a specific host dependant on antigen shape (vaccines are based on shape of antigens)
viruses only enter their specific cells
host range : the number of species, tissues or cells that can be specially infected
some viruses can create an envelope (when leaving a host cell and part of the host cells membrane wraps around the virus
structure of virus : head/capsid, DNA
many different structures of viruses
human viral disease examples : poxviruses : smallpox, direct contact and airborne droplets
viruses can be transmitted through direct contact, inhalation
Epidemic : large outbreak of disease in a certain region
Pandemic : outbreak of disease over a huge region sometimes globally
lytic cycle
attach & insert
bacteriaphage attaches and inserts itself into a bacteria (use antigens to ID attached to host, inject DNA)
synthesis
use host organelles to make new viral components ( NOT a cell ), use viral DNA as instructions
assembly
put together components to make virus clones
lysis (release)
new virus burst (lyse) the host cell releasing to infect others
lytic cycle leads to immediate symptoms
lysogenic cycle:
1. still attach and insert
bacteriaphage attaches and inserts itself into a bacteria (use antigens to ID attached to host, inject DNA)
after viral DNA is inserted it combines with host DNA
so that when the host reproduces the viral DNA will also be copied (viral DNA lays dormant until activated : then enters lyctic cycle)
