Ch. 5 Virology

Question 1

Can virions diffuse through the plasma membrane?

Question 2

What is the first step of entry?

Answer 2

adherence to the plasma membrane, mediated by binding to a specific cell receptor

Question 3

The first molecule on a cell’s surface found to be essential for virus binding is known as the

Answer 3

receptor

Question 4

additional surface molecules that may be necessary for virus binding are known as

Answer 4

coreceptors

Question 5

Presence/absence of receptors on certain cells determine

Answer 5

host range tissue tropism

Question 6

First cell receptor identified:

Answer 6

Sialic acid (1985)

Question 7

three technologies allowed detection of receptors:

Answer 7

1. Production of monoclonal antibodies- isolating and characterizing individual surface proteins 2. DNA-mediated transformation-isolating the code for the receptor protein and introducing it to cells that were previously unsusceptible 3.molecular cloning-clone and express receptor of virus

Question 8

immunoprecipitation

Answer 8

Question 9

Experimental strategy for isolating cell receptor gene if cell is lysogenic:

Answer 9

Encode virus with drug resistance genes, introduce to cells that have had different bits of DNA from a receptor positive cell added. add drug, only receptor positive cells survive. look at dna changes

Question 10

Experimental strategy for isolating cell receptor genes if cell is lytic:

Answer 10

Fluorescent virus is added, and cell color is monitored

Question 11

What receptor was added to mouse cells in order to study poliovirus?

Answer 11

CD155

Question 12

What is the cell receptor for influenza?

Answer 12

sialic acid

Question 13

Receptor that binds with HIV protein GP 120 (the lollipop), which is attached to the capsid via GP 41

Answer 13

CD4

Question 14

What sialic acid linkage is present in human cells?

Answer 14

2,6

Question 15

What kind of cell entry methods relies on clathrin capsid forming proteins to endocytose the virus?

Answer 15

Clathrin dependent endocytosis. Virus binds to receptor proteins, in an invagination. The ligand receptor complex diffuses into the invagination of clathrin coated plasma membrane, which further invaginates and pinches off, facilitated by GTPase Dynamin. This fuses with early endosome. Lower pH can induce uncoating

Question 16

Viral movement along microtubules is conducted by ____ motors. Viral movement along microfilaments is conducted by ____ motors.

Answer 16

kinesin and dynein; myosin

Question 17

Genomes can enter the cell’s nucleus by:

Answer 17

passing through the nuclear pore complex.

Capsids can pass for very small virus, some virus capsids minimally disassemble (herpes), some substantially disassemble (adenovirus)