Micro ch 13--Viruses, Viroids, Prions

viruses

obligate intracellular parasites that can infect all five kingdoms

made of a nucleic acid core and a protein coat

virion

fully developed virus

capsid

protein coat

spikes

carb or protein projections

host range

types of cells a microbe can infect

helical

type of virus

long tubular rod

polyhedral/isohedral

type of virus

many sided

enveloped

type of virus

surrounded by a capsule of some type

complex

type of virus

extra structures such as tails and fibers

several ways to grow viruses

in bacteria

in living animals

in chicken eggs

tissue culture

3 ways to identify viruses

antibodies

DNA sequencing

electron microscope

bacteriophage

a virus infects a bacteria

bacteriophage lytic cycle

1. virus binds to bacterial wall

2. lysozyme is released and breaks a hole in the bacterium

3. the viral nucleic acid is injected into the cell

4. the nucleic acid takes over the cell parts and makes more nucleic acid in a protein coat

5. nucleic acid and protein coats assemble

6. lysozyme is produced and breaks the cell open, the virus is released

bacteriophage lysogenic cycle

1. the virus binds, injects DNA into the cell

2. DNA inserts into the host DNA, now called the prophage, which stays dormant

3. copied every time the bacterium reproduces, and can switch at any time to the lytic cycle

animal virus life cycle

1. the virus attaches to inherited proteins on the animal cell membrane

2. the virus is engulfed

3. the nucleic acid and protein coat separate

4. copies are made of the genome and protein coat

5. the virus assembles

6. the virus breaks through the membrane or buds off with the host membrane around it, or inserts into the host DNA, called a provirus, which can stay dormant and break open the cell or form a tumor

inclusion body

abnormal clump of material in the cell

polykaryocytes

several cells fused together

oncogene

a normal gene that has been changed and produces a cancer cell

papova

DNA virus that causes warts and tumors

adeno

A DNA virus that causes respiratory tract infections

herpes

DNA virus that causes cold sores, chicken pox, and sexual herpes

pox

DNA viruses that cause smoll pox and cow pox

picorna

RNA virus

causes polio, common colds, and Hepatitis

toga

RNA virus

causes encephalitis and yellow fever

orthomyxo

RNA virus

causes influenza

paramyxo

RNA virus

causes measles and mumps

rhabdo

RNA virus

causes rabes

retro

causes leukemia, AIDS and feline leukemia

glycoprotein 120

inhibits the affects of interferonson

oncogenic viruses

DNA viruses

cause tumors or cancer

Papilloma

strand 16

DNA virus

causes warts and cancer

Epstein-Barr virus (EB)

causes infectious mononucleosi

transforms cells to Burkitt’s lymphoma, Hodgkin’s disease, and nasopharyngeal carcinoma

Herpes 1

causes cold sores

Herpes 2

causes sexual herpes and cervical cancer

Hepatitis B and C

can cause liver cancer

acute infection

sudden, short lasting

chronic infection

slow or long lasting

latent viral infection

hoouses the virus for a long time without causing disease

can reactivate in the future

prion diseases

infectious protein

the protein causes degeneration of the brain

viroids

short pieces of RNA with no protein coat

mostly affects plants

oncolytic virus

enter cancer cells and causes them to rupture

used as cancer treatment