all viruses have same basic structure:

nucleic acid can be DNA or ___; circular or ____; single or ____ stranded

some viruses store specialized enzymes inside their ____

many animal viruses have an ____

nucliec acid core surrounded by capsid (protein coat)

RNA; linear; double

capsids

envelope

host range =

tissue tropism=

host range = types of organisms infected

tissue tropism = types of cells infected

viruses hijack cell's txn and tln machineries to express:

which results in assembly and release of viruses

early genes

middle genes

late genes

helical

icosahedral

complex shapes

T-even phages =

pox viruses =

T-even phages = binal symmetry

pox viruses =mutilayered capsid

most RNA viruses are ___-____

replicated in host cell's ___

retroviruses (HIV) employ __ ___

most DNA viruses are ___-___

replicated in ___

single stranded

cytoplasm

reverse transcriptase

double stranded

nucleus

bacteriophage exhibit 2 cycles.

lytic :

lysogenic :

lytic phages are called ___

lysogenic phages ____

lytic : virus kills the host cell

lysogenic: virus incorporates into the cells genome

virulent

temperate

Lytic cycle

Adsoption:

penetration:

synthesis:

assembly:

release:

Adsoption: virul attachent

penetration: viral entry

synthesis: viral components made

assembly: components put together

release: viral exit

lysogenic cycle

virus integrates into cellular genome as a ___

propagates along with ___ ___

resulting cell is called ____

prophage

host genome

lysogen

 the prophage alters the bacterial phenotype

-vibrio cholerae toxin is viral-encoded

HIV targets ___ cells, mainly ____ __ cells

without these, body cannot mount an effective __ __

host ma ultimately die from a variety of ___ ___

CD4+, helper T

immune response

opportunistic infections

HIV infection cycle

attachment =

entry =

replication =

assembly =

release =

attachment =viral gp 120 attaches to CD4 and a co-receptor on host cells

entry =by endocytosis (CD4 only) or fusion (CD4 and acoreceptor CXCR4 or CCR5)

replication = reverse transcriptase converts RNA to double stranded DNA

assembly = occurs after a variable period of dormancy

release = new viruses exit by budding

During an infection, HIV is constantly ___ and ___

initially, gp120 uses ___ as a coreceptor

later, ____ is used

replicating and mutating

CCR5

CXCR4

highly active antiretroviral therapy

AZT and protease inhibitors

Type _ flu is serious epidemic

Type _ and _ flu are mild infections

hemagglutinin helps in viral ___

neuraminidase helps in viral ___

A

B and C

entry

exit

H and N proteins are constantly ____

 thus we have yearly ___ ___, not vaccines

type A viruses are classified into __ H subtypes and __ N subtypes

changing

flu shots

16, 9

flu viruses can also undergo __ ___ when 2 subtypes infect a cell

creates novel combinations of ___, unrecognizable to human antibodies

antigenic ___ caused pandemics

genetic recombinatiion

spikes

shifts

causes deadly pneumonia

natural host is deer mouse

cause sever hemorrhagic fever

host is unknown

SARS stands for...

caused by ___

host is the ___

RNA genome contains ___ main genes

SARS vaccines currently being developed

sever acute respiratory syndrome

coronavirus

civet

6

viruses cause cancer by altering the ___ ___ of human cells

1. triggering expression of _____
2. disrupting ___-___ genes

growth properties

1. oncogenes
2. tumor-suppressor genes

prions

"___ ___" particles

cause TSEs, stands for...

like:

normal prion abbrev:

misfolded, disease causing protein abbrev:

proteinaceous infectious

transmissible spongiform encephalopathies

madcow, scrapie, creutzfeldt-jacob disease

PrP^c

PrP^sc

Viroids are ...

resemble introns of ___ genes

200-400 nucleotides long

resistant to ____

cause diseases in ___

tiny naked molecules of ___ RNA

rRNA

degredation

plants