AP Bio Chapter 18 Viruses

300282500	Capsid	protein shell enclosing a viral genome
300282501	Viral envelopes	accessory part of virus that is derived from membrane of the host cell containing marker proteins of the host, allowing it easy entry
300282502	Bacteriophages	viruses that infect bacteria
300282503	Host range	the range of host cells a virus can have
300282504	Lytic cycle	culminates in the death of the host, bacteria breaks open and releases phages
300282505	Virulent phage	reproduces only by the lytic cycle
300282506	Restriction enzymes	enzymes that cut DNA at specific sites
300282507	Lysogenic cycle	replicates phage genome without destroying the host
300282508	Temperate phages	can use both lytic and lysogenic stage
300282509	Prophage	when viral DNA is integrated through crossing over; mostly silent within the bacterium,
300282510	Retroviruses	virus with RNA as genetic material
300282511	Reverse transcriptase	enzyme that turns RNA into DNA
300282512	HIV/AIDS	retrovirus that containt two identical molecules of single stranded RNA and two molecules of reverse transcriptase
300282513	Vaccines	harmless variants or derivatives of pathogenic microbes that stimulate the immune system to mount defenses against the actual pathogen
300282514	Provirus	integrated viral DNA of HIV, never leaves hosts' genome, remains permanent resident of the cell
300282515	Transformation	alteration of a bacterial cell's genotype and phenotype by the uptake of naked, foreign DNA from the surrounding environment
300282516	Conjugation	direct transfer of genetic material between two bacterial cells that are temporarily joined
300282517	Plasmid	small, circular, self-replicating DNA molecule separate from bacterial chromosome
300282518	F factor	ability to donate DNA during conjugation
300282519	episome	genetic element that can replicate either as part of the bacterial chromosome or independently
300282520	R plasmids	genes that are resistant for certain antibiotics
300282521	transposable elements	ALWAYS part of chromosomal or plasmid DNA, move from one site in cell's DNA to another target site, cut and paste or copy and paste mechanism
300282522	insertion sequences	simplest transposable elements. contains a single gene, which codes for transposase. only bacteria
300282523	transposons	longer, more complex, also move about in bacterial genome. contain extra genes, such as for antibiotic resistance
300282524	operon	operator, promoter, and the genes they control
300282525	operator	switch that controls gene expression
300282526	repressor	can switch off the operon by attaching to the oeprator and blocking attachment of RNA polymerase to the promoter
300282527	regulatory gene	regulates the creation of the repressor, has its own poromoter
300282528	corepressor	small molecule that operates with a reperssor to turn an operon off
300282529	inducer	specific molecule that inactivates the repressor
300282530	cyclic AMP	small organic molecule that accumulates when glucose is scarce
300282531	activator	promotes gene expression; positive regulation
300282532	viroids and prions	smaller, circular RNA molecules and proteins