Viruses and Prions

Question 1

polio, enterovirus, rhinovirus, hep A, or cocksakie combined with positive sense RNA naked icosahedral virus indicates________

Answer 1

picornaviridae

Question 2

single strand, naked icosahedral that causes hep E or norwalk virus (norovirus) indicates____

Answer 2

caliciviridae (calix cup)

Question 3

rubella (German measles), or equine encephalitis matched with enveloped icosahedral +ssRNA

Answer 3

togaviridae

Question 4

west nile virus, hep c virus, tick/mosquito borne matched with +ssRNA, enveloped virus

Answer 4

flaviviridae

Question 5

+ssRNA, enveloped helical nucleocapsids surrounded by glycoproteins, SARS, MERS

Answer 5

coronaviridae

Question 6

which kinds of viruses cause common cold?

Answer 6

rhino, adeno, corona, paramyxiviridae

Question 7

helical nucleocapsid, enveloped, H and N glycoproteins surrounding envelope, contains RNA transcriptase, segmented genome (8)

Answer 7

orthomyxoviridae (influenzaviridae)

Question 8

What does hemagglutinin do? What does neuraminidase do?

Answer 8

Both are spikes on the orthomyxoviridae envelope (-ssRNA helical and segmented). Hemaglutinin is used for attachment of the virus to the host cell (attaches to sialic acid). Neuraminidase are enzymes that free the newly synthesized virus from the cells (helps it bud off).

Question 9

changes in RNA at single residues, causing little change

Answer 9

genetic drift/ point mutations

Question 10

whole segments substituted in viruses with segmented genomes (ie influenza) and in cells infected with more than 1 strain of the virus. Causes Pandemics, big change.

Answer 10

genetic shift/ reassortment

Question 11

Enveloped helical -ssRNA unsegmented genome, F protein causes syncytium formation, patient presents with mumps, respiratory tract infections, RSV, also common cold and measles

Answer 11

paramyxoviridae

Question 12

Bullet-shaped enveloped helical -ssRNA, causes encephalitis and is fatal

Answer 12

rhabdoviridae

Question 13

Describe pathogenesis of rabies

Answer 13

Person is bitten by rabid animal, virus multiplies in muscle tissue and travels through axons to CNS. Virus replicates in gray matter of neurons and forms inclusion bodies in hippocampus and cerebellum.

Question 14

Describe the three stages of rabies

Answer 14

1-Prodromal- nonspecific; may have abnormal sensations at site of bite
2-Excitation phase- increasing anxiety, eye problems, hydrophobia
3-Paralytic phase- progressive general flaccid paralysis. Apathy to stupor to coma, peripheral vascular collapse and death

Question 15

Long pleomorphic enveloped helical -ssRNA, looks like thread hanging off end, causes hemorrhagic fevers in men and moneys, ebola nad marburg virus

Answer 15

filoviridae

Question 16

Enveloped helical -ssRNA with segmented genome, arboviruses and hantaviruses in this group

Answer 16

bunyaviridae

Question 17

Negative ssRNA, causes lassa virus and lymphocytic choriomeningitis

Answer 17

arenaviridae (arenosus-sandy)

Question 18

How do protease inhibitors work, and what virus are they used against?

Answer 18

Since HIV has an envelope, proteases are needed to cleave active proteins (GAG, POL and ENV-120 and 41), which is necessary for the viability of the virion (cleavage needed for budding). Protease inhibitors stop this process, and can halt the spread of the virus

Question 19

Describe features of retroviridae and name the three types

Answer 19

• Enveloped virus particles with two +ssRNA
• Uses reverse transcriptase to make a dsDNA intermediate tha goes into host chromosome
• Types are HTLV1 and HTLV2 and Lentiviridae

Question 20

What transforming virus is associated with adult t-cell leukemia/lymphoma, transmitted via blood, and is enveloped with two idential copies of +ssRNA?

Answer 20

HTLV1 and HTLV2

Human T-Cell Lymphotrophic Viruses

Question 21

HIV specificity protein that forms the ‘stick of lollipop’ and attaches to viral membrane, includes fusion proteins

Answer 21

Glycoprotein 41 (gp41)

Question 22

HIV specificity protein that binds to CD4 and contains cells and a coreceptor, is ‘head of lollipop’; undergoes much antigenic drift in chronic HIV infection

Answer 22

Glycoprotein 120 (gp120)

Question 23

HIV specificity protein that is present on T cells

Answer 23

CXCR4

Question 24

HIV specificity protein that is present on macrophages and some T cells

Answer 24

CCR5

Question 25

What is the molecular disease process of prions?

Answer 25

• PrPsc, protease resistant prion protein causes molecular switch of cellular protein PrPc to the prion conformation.
• Altered protein cannot be degraded by cellular proteases and accumulates in cytoplasm and extracellular areas of cells in the brain.

Question 26

What type of virus is characterized by long incubation periods and attack of immune cells?

Answer 26

lentivirus

Question 27

Describe some differences between HIV1 and HIV2

Answer 27

HIV2 less prevalent, endemic to W Africa, less virulent with slower rate of disease progression. Both simian viruses are similar

Question 28

Describe the structure of the HIV virus

Answer 28

enveloped virion with two +ssRNA, reverse transcriptase (RNA dependent DNA polymerase), integrase, and two tRNAs, also gp41 and gp120 on the envelope

Question 29

What is the receptor for HIV-1? What kind of tropic cells are bound first (and what chemokine receptor is associated)? Which ones second?

Answer 29

CD4 is receptor for HIV-1.
First M-tropic cells are infected (CCR5)
Then T-tropic cells are infected (CXCR4)

Question 30

CJD, vCJD, FFI, BSE are all _____ diseases

Answer 30

prion diseases