Week 4 Reading Quiz Week 8

Question 1

Single folded polypeptide chain

Answer 1

Subunit

Question 2

Unit from which capsids or nucleocapsids are built; may comprise one protein subunit or multiple different protein subunits

Answer 2

Structural Unit

Question 3

The protein shell surrounding the nucleic acid genome

Answer 3

Capsid

Question 4

The nucleic acid-protein assembly packaged within the virion; used when this assembly is a discrete substructure of a particle.

Answer 4

Nucleocapsid

Question 5

The host cell-derived lipid bilayer carrying viral glycoproteins.

Answer 5

Envelope

Question 6

The infectious virus particle.

Answer 6

Virion

Question 7

A structure that has not attained the lowest free energy state.

Answer 7

Metastable Structure

Question 8

The minimal size of an object that can be distinguished by microscopy or other methods of structural analysis.

Answer 8

Resolution

Question 9

The symmetry of regularly wound structures defined by the relationship P = u x p where P = pitch of the helix u = the number of structural units per turn and p = the axil rise per unit.

Answer 9

Helical Symmetry

Question 10

The symmetry of an icosahedron the solid with 20 faces and 12 vertices related by axes of two three and five fold rotational symmetry.

Answer 10

Icosahedral Symmetry

Question 11

A protein carrying covalently linked sugar chains (oligosaccharides).

Answer 11

Glycoprotein

Question 12

Proteins that are embedded in a lipid bilayer with external and internal domains connected by one or more membrane-spanning domains.

Answer 12

Integral Membrane Proteins

Question 13

A segment of an integral membrane protein that spans the lipid bilayer and that is often alpha-helical.

Answer 13

Membrane Spanning Domains

Question 14

The 2 main functions of virion proteins are __ and ___ of the viral genome

Answer 14

Protection; Delivery

Question 15

Why are virus particles considered “metastable”?

Answer 15

Because they need to be strong enough to protect the viral genome and labile enough to be released or uncoated inside the host cell.

Question 16

As individual proteins assemble to form a large capsid, their surface charge and polarity is ____ while their contact region is ____. This leads to a __ in the energy of the capsid system and provides the driving force for capsid ___.

Answer 16

minimized ; maximized ; decrease ; self-assembly

Question 17

Which are the smallest thing scientists can see when using X-ray crystallography?

Answer 17

Atoms

Question 18

Which of the following structures were determined by X-ray crystallography?
a
DNA

b
Penicillin

c
Vitamin B-12

d
Insulin

e
Hemoglobin

f
All of the above

Answer 18

All of the above

Question 19

What are some of the limitations of X-ray crystallography?

a
Requires proteins are packed together in stable organized crystal

b
Some proteins are too floppy to line up in a crystal.

c
Requires the formation and creation of crystals.

d
All of the above

Answer 19

d. All of the above

Question 20

What are some characteristics of Cryo-EM?

a
Uses electrons rather than light as energy source.

b
Computer algorithms assemble multiple pictures of sample into one composite 3D image.

c
Proteins in sample can be in multiple orientations.

d
Proteins are kept in thin layer of liquid and frozen.

e
All of the above

Answer 20

All of the above

Question 21

An icosahedron comprises _ equilateral triangular faces related by _, __, and __ axis of rotational symmetry.

Answer 21

20 ; 5 ; 3 ; 2