question

Plaque

answer

clearings visible against lawn of bacterial growth on surface of agar from bacteria being destroyed ; determine concentration of viral suspension in PFU's

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Prion

answer

an infectious protein that causes spongiform encephalopathies; inherited and transmissible by ingestion, transplant, and surgical instruments; cause normal cell surface proteins to misfold

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Capsid

answer

protein coat that protects nucleic acid of virus; made up of capsomeres

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Capsomere

answer

repeating protein subunits that make up a capsid

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Envelope

answer

outer membrane surrounding the capsid of some viruses; made of proteins, lipids, carbs; usually taken from the host cell's plasma membrane; unique to animal viruses

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Spike

answer

carb-protein complexes projecting from envelope meant for attachment

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Virion

answer

fully developed virus

question

Complex Virus

answer

a virus with a complicated structure such as a bacteriophage, made from bacterial cell components, sits on cell and injects

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Viruses

answer

obligatory intracellular parasites; have DNA or RNA; mostly infect only specific types of cells in one host

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Host Range

answer

determined by specific host attachment sites and cellular factor; the type of cells and organisms a virus can effect

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Virion Structure

answer

nucleic acid, capsid, envelope, spikes

question

Helical Virus

answer

rabies and ebola virus have this morphology

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Family Names

answer

end in viridae

question

Genus Names

answer

end in virus

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Viral Species

answer

a group of viruses sharing the same genetic information and ecological host; common names are used for this like influenza virus or ebola virus

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Subspecies

answer

designated by a number such as H1N1 influenza virus

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Animal Viruses in Lab

answer

require either cell culture, embryonated eggs, or living animals

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Bacteriophages in Lab

answer

require Host cell lawn; infection is visible as clear plaques

question

Cytopathic effects

answer

viruses can be identified by observing this cell deterioration; when cells are sick they ball up; loss of contact inhibition

question

Serological tests

answer

viruses can be identified by detecting antibodies against viruses and using antibodies to identify the viruses

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PCR

answer

can help identify viruses by using nucleic acids

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Attachment (Lytic Cycle)

answer

phage attached by tail fibers to host cell

question

Penetration (Lytic Cycle)

answer

phage lysozyme opens cell wall; tail sheath contracts to force tail core and DNA into cell

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Biosynthesis (Lytic Cycle)

answer

production of phage DNA and proteins, needs to use bacterial cell enzymes

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Maturation (Lytic Cycle)

answer

assembly of phage particles

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Release (Lytic Cycle)

answer

phage lysozyme breaks cell wall and new phages are free

question

Bacteriophage Multiplication

answer

cannot multiply without host cell, must use host to produce viral enzymes and components; can multiply via lytic or lysogenic stage

question

Lytic Cycle

answer

phage causes lysis and host cell death

question

Lysogenic Cycle

answer

phage remains latent, prophage DNA incorporated into host DNA; cells are immune to reinfection by same phage; phage conversion

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Prophage

answer

inserted phage DNA; gives bacteria the ability to make toxins

question

Phage Conversion

answer

bacterial host cell has new properties; bacteriophage genes make bacterial cells more pathogenic

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Attachment (Animal Virus)

answer

viruses attach to cell membrane, do not have tail fibers

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Penetration (Animal Virus)

answer

by endocytosis or plasma membrane fusion

question

Uncoating

answer

coating is removed by viral or host enzymes

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Biosynthesis (Animal Virus)

answer

production of nucleic acid and proteins

question

Maturation (Animal Virus)

answer

nucleic acid and capsid proteins assemble

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Release (Animal Virus)

answer

by budding (enveloped viruses) or rupture

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Pinocytosis

answer

very tiny endocytosis

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Latent Virus

answer

a virus that is inactive; example: herpes, chicken pox, HIV

question

Hepadnaviridae and Retroviridae

answer

families that have reverse transcriptase

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Reverse Transcriptase

answer

enzyme that uses viral RNA as a template to produce complementary double stranded DNA

question

Oncogenic Virus

answer

virus that causes cancer

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HIV Phase 1

answer

asymptomatic/chronic lymphadenapathy; population of HIV in the blood peaks to about 10 million/mL the first 2 months; CD4+ T Cells plunge, then recover; detectable antibodies appear causing rapid HIV decline; HIV stabilizes in blood 1,000-10,000 per mL

question

HIV Phase 2

answer

symptomatic/early indication of immune failure (fever diarrhea rash); CD4+ cell population declines steadily; huge indefinite numbers of HIV in lymphoid tissue; 100 billion new made every day; Clinical AIDS, CD4+ T cell population drops to under 200 cells per microliter

question

HIV Phase 3

answer

AIDS indicator conditions; HIV levels in blood rise as immune system breaks down

question

HIV attachment

answer

CD4 receptor and coreceptor bind to HIV spike; then fusion by receptor mediated endocytosis

question

Reverse Transcriptase Inhibitors

answer

are either a cocktail of many drugs that must be taken at once or are nucleoside analogs that cause termination of viral DNA by competitive inhibition

question

Oncogenes

answer

part of DNA that makes a cell cancerous when activated; 10% of cancers are caused by viruses

question

Transformed Cells

answer

cells that have increased growth and loss of contact inhibition

question

Human Papillomavirus

answer

causes cervical cancer

question

Hepatitis B Virus

answer

causes liver cancer

question

Human T Cell Leukemia Virus

answer

causes T Cell Leukemia

question

Feline Leukemia Virus

answer

causes Feline Leukemia

question

PrPc

answer

normal cellular prion protein, on cell surface

question

PrPsc

answer

scrapie protein; accumulates in brain cells, forming plaques

question

Pros to Phage Therapy

answer

alternative to antibiotics; more specific than antibiotics; good for biofilms

question

Cons to Phage Therapy

answer

bacteria may become resistant; endotoxins released by dying bacteria; need cocktail of phages for each infection; patient specific treatment

question

1981

answer

in US, cluster of Pneumocystis and Kaposi's sarcoma was discovered in young homosexual men on this date; they showed loss of immune function

question

1983

answer

discovery of virus causing loss of immune function on this date

question

Structure Of HIV

answer

mRNA, reverse transcriptase, capsid, envelope, and spikes

question

Active HIV in CD4+T Cells

answer

provirus is activated. allowing it to control the synthesis of new viruses, which bud from host cell. Final assembly takes place at cell membrane, taking up viral envelope proteins as the virus buds from the cell

question

Latent HIV in CD4+ T Cells

answer

viral DNA is integrated via integrase enzyme into cellular DNA and forms a provirus that can later be activated to produce infective viruses

question

Active HIV in Macrophage

answer

new viruses are produced from provirus; completed virions are either released or persist in the macrophage within vacuoles

question

Latent HIV in Macrophage

answer

HIV can persist either as a provirus or as a complete virion in vacuoles

question

HIV Transmission

answer

sexual contact, transplacental infection of fetus, blood-contaminated needles, organ transplants, artificial insemination, blood transfusion

question

85%

answer

percentage worldwide of AIDS transmitted through heterosexual intercourse

question

Protease Inhibitors

answer

HIV is not able to make capsid

question

Fusion Inhibitors

answer

HIV can not fuse to host cell membrane

question

Animal Viruses

answer

can be double stranded DNA or double stranded RNA or retroviruses

question

Retroviruses

answer

viruses that use reverse transcriptase to make DNA from an RNA template

question

Example of Enveloped Viruses

answer

HIV and influenza virus

question

Examples of Prion Diseases

answer

Creutzfeld Jakob disease, Kuru, Bovine Spongiform Encephalopathy, Sheep Scrapie, Familial Insomnia

question

HIV Spike

answer

glycoprotein, base is GP 41 and tip is GP 120

question

Coreceptor on T Cells

answer

CCR5 or CXCR4

question

AIDS Infection

answer

HIV DNA integrates into the host chromosome- provirus

question

HAART

answer

highly active anti retroviral treatment; 40 pills a day, reverse transcriptase inhibitors, protease inhibitors, integrase inhibitors, fusion inhibitors

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