19.2 Viruses

why are viruses not considered living?

because they cannot perform certain living functions like metabolism and reproduction without host

what are viruses made out of

nucleic acid, protein, and sometimes lipids

why do we study viruses?

because they infect us

what is virus protein coat called

capsid

what are viruses that infect bacteria called

bacteriophages

what are three ways to classify viruses?

type of genetic information, shape, and presence of lipid envelope

can viruses have both DNA and RNA at the same time for genetic information?

no

what part of virus helps it get accepted by cell?

spike protein

what part of cell accepts the virus?

cell receptors on cell surface

what are the two types of infection?

lytic infection and lysogenic infection

what happens in lytic infection?

virus takes over metabolism and make copies, then cell is burst and viruses are released

what happens in lysogenic infection?

virus DNA becomes part of host, is reproduced along with host DNA, and eventually enters lytic stage

what is the viral DNA embedded in host's DNA called?

prophage

what are retroviruses

viruses that contain RNA as genetic information

What does reverse transcriptase do?

converts RNA to DNA

why does reverse transcriptase cause many new virus mutations?

it lacks proofreading function unlike DNA duplication

where did viruses come from?

possibly genetic information that could move freely between cells

what are vaccines?

a weakened, dead, or section of virus that is used to train adaptive immunity system

how do vaccines work?

produces reaction from immune system with antibodies, which will make future infection easier to fight