Question | Answer |
all viruses are considered what | parasites |
viruses can only be seen with what kind of microscope | electron |
4 qualities of life | composed of one or more cells, grow, use energy to maintain survival, reproduce |
traits of life viruses show | carry genetic info for reproduction, respond to changes in environment, can evolve and adapt to environment |
nonliving traits viruses show | lack cell membrane, no metabolism, don't grow, don't use own energy for reproduction,can only reproduce in host cell, no signs of life when outside cell, obligate intracellular parasites |
broad based viruses | viruses that can affect many different animals |
viruses can only invade cells with the correct __________ on the cell membrane that the virus can connect to | receptor |
what method do viruses use to see which cell they can enter? | lock and key |
bacteriophages | viruses that infect bacteria |
docking | viruses use proteins on cells outer coat to latch onto a cell membrane so it can enter |
penetration | goes through the cell membrane and into the host cytoplasm |
biosynthesis | making of the viral components |
maturation | virus parts assemble themselves |
release | cell breaks open killing it and releases virus to infect other cells |
lytic infections | virus that can harm the cell |
lysogenic infection | provirus that will replicate with other DNA when the cell divides but does not harm the cell |
provirus | virus that does not harm cell |
how can a lysogenic virus become lytic | when something signals it and new viruses are created and the cell bursts releasing it |
retroviruses | use RNA instead of DNA. contain a code that produces an enzyme that converts the RNA into DNA |
three ways viruses go from human to human | through the air or contact with infected surfaces, direct physical contact, exposure to blood of an infected person. |
do antibiotics work on viruses? | no |
how does a vaccine work | inject a harmless virus into body which will cause immune system t recognize invader and develop antibodies to recognize and kill it if encountered again |
who developed the first vaccine? | Edward Jenner |
can vaccines cure viral infections? | no they can only help prevent them |
interferon | protein produced by cells in your body when exposed to a virus |
what do interferons do | interfere with the ability of a virus to enter the cell and replicate |
antiviral drugs | drugs used to treat viral infections. do not harm virus, just greatly slow down their reproduction inside cells |
viral therapy | when a gene is inserted into the cells of a person who does not have that gene |
example of viral therapy | insulin for diabetes |
how do scientists make a virus for gene therapy? | remove infectious DNA and insert a gene |