Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
20 Cards in this Set
- Front
- Back
|
viruses |
minuscule, acellular infectious agent w/DNA,RNA obligate parocite cannot carry out any metobolic pathway neither grows or responds to environment cannot reproduce independtly no cytoplasmic membrane, cytosol, organelles recruit cells metabolic payways to increase extracellular & intracellular state |
|
|
extracellular state |
viron protein coat surrounds nucleic acid nucleic acid & capsid called nucleocapsid some have phospholipid envelope (from host) outermost layer provides protection & recognition site for host cells |
|
|
intracellular state |
capsid removed virus exist as nucleic acid |
|
|
host of viruses |
most viruses infect only particular cell all types of organisms susceptible bacteriphage virus infects bacteria plant viruses infect food crops fungal virus not studied(no extracellular state) |
|
|
capsids |
provide protection for viral nucleicacid means of attachment to hosts cell composed of proteinaceous subunits CAPSOMERS: made of single or multiple protein |
|
|
viral envelope |
aquired from host cell durring viral replication or release envelope is portion of membrane system to host composed of phospholipid bilayer & proteins some proteins virally coded glycoproteins (spiked) envelope proteins & glycoproteins often play a role in host recognition |
|
|
classification of viruses |
classified by nucleic acid, presence of envelope, shape and size |
|
|
lytic replication |
viral replication results in death & lysis of host cell 5 stages of lytic rep cycle: attachment entry synthesis assembly release |
|
|
lysogeny |
modified replication cycle infected host cells grow and reproduce normal for generation before they lise temperate phages prophages-inactive phages lysogenic conversion results when phages carry genes that alter phenotype of a bacterium (shingles) |
|
|
roles of viruses in cancer |
cell division under strict genetic code genes dictate that some cells no longer divide cells that can divide are prevented from unlimited division
genes for cell division are turned off or genes inhibiting division are turned on |
|
|
neoplasia |
uncontrolled cell division in multicellular animal mass of neoplastic cells is tumor |
|
|
benign vs malignant tumors |
malignant tumors also called CANCER metastasis occurs when tumors spread |
|
|
factors that contribute to activation of oncogenes |
ultraviolet light radiation carcinogens viruses |
|
|
viruses cause 20-25% human cancers |
some carry copies on oncogenes as part of their genomes some promote oncogenes already present in host interfere with tumor repression specific viruses that cause 15% cancer burkitts lymphoma hodgkins disease kaposis sarcoma cervical cancer |
|
|
why are DNA viruses more likey to cause neoplasias than RNA viruses? |
DNA carries promoter and replicates |
|
|
culturing viruses in lab |
viruses cannot grow in standard microbilogical media cultured in host cells |
|
|
3 types media for culturing viruses |
media consisting of mature organisms chicken eggs cell tissue culture |
|
|
viroids |
small circular pieces RNA that are infectuous and pathogenic in plants similar to RNA viruses but lack capsid may appear linear because of hydrogen bonding |
|
|
prions |
proteinatious infectious agents cellular PrP: made by all mammals a-helices Prion PrP: disease causing form B-sheet *Prion PrP causes cellular PrP to refold into Prion PrP |
|
|
prio diseases |
spongiform encephalopathies: large vacuoles in brain, spongy appearance transmitted by ingestion, transplantation or contact of mucous w/ infected tissues prions destroyed by incineration or auto claving in concentrated sodium hydroxide |
