chapter 13: viruses, viroids, and prions Flashcards
virus
obligate intracellular parasite; require living host cells to multiply; contain DNA or RNA; contain protein coat; no ribosomes; no ATP-generating mechanism; acellular; no metabolism
virus capsid
the outer protein shell
virus envelope
an outer membrane taken from a previous victim
bacteriophage
viruses that only infect bacteria and often only specific strains of bacteria
lytic cycle
phage causes lysis & death of host cell;
→ attachment: phage attaches to host cell → penetration: phage lysozyme opens cell wall & tail core / DNA is forced into cell → biosynthesis: production of phage DNA & proteins → maturation: assembly of phage particles → release: phage lysozyme breaks cell wall
lysogenic cycle
→phage DNA incorporates into host cell DNA → inserted phage DNA is known as prophage → host cell replicates chromosome → replicates prophage DNA → results in phage conversion → host cell exhibits new properties
what is the name of a bacteriophage in the lysogenic state?
prophage
what is the name of a bacteriophage in the lysogenic state?
prophage
lysogeny
phage remains latent
transduction
a form of horizontal gene transfer in which genetic information is transferred from one host to another by a virus
oncogenic viruses
viruses that cause cancer
viroid
virus without a capsid (protein coat); infect plants
prion
infectious misfolded proteins; protein denatured to a shape that is “nonfunctional transmissible”; when a protein interacts while in a nonfunctional transmissible conformation with a functional protein, they end up in a prion conformation
transmissible spongiform encephalopathies (TSEs)
caused by prions; contagious lethal diseases that makes holes in the brain
ex) bovine spongiform encephalopathy (mad cow disease), scrapie, creutfeldt-jakob disease, kuru
