Week 4 Reading Quiz Week 8 Flashcards
Single folded polypeptide chain
Subunit
Unit from which capsids or nucleocapsids are built; may comprise one protein subunit or multiple different protein subunits
Structural Unit
The protein shell surrounding the nucleic acid genome
Capsid
The nucleic acid-protein assembly packaged within the virion; used when this assembly is a discrete substructure of a particle.
Nucleocapsid
The host cell-derived lipid bilayer carrying viral glycoproteins.
Envelope
The infectious virus particle.
Virion
A structure that has not attained the lowest free energy state.
Metastable Structure
The minimal size of an object that can be distinguished by microscopy or other methods of structural analysis.
Resolution
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.
Helical Symmetry
The symmetry of an icosahedron the solid with 20 faces and 12 vertices related by axes of two three and five fold rotational symmetry.
Icosahedral Symmetry
A protein carrying covalently linked sugar chains (oligosaccharides).
Glycoprotein
Proteins that are embedded in a lipid bilayer with external and internal domains connected by one or more membrane-spanning domains.
Integral Membrane Proteins
A segment of an integral membrane protein that spans the lipid bilayer and that is often alpha-helical.
Membrane Spanning Domains
The 2 main functions of virion proteins are __ and ___ of the viral genome
Protection; Delivery
Why are virus particles considered “metastable”?
Because they need to be strong enough to protect the viral genome and labile enough to be released or uncoated inside the host cell.
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 ___.
minimized ; maximized ; decrease ; self-assembly
Which are the smallest thing scientists can see when using X-ray crystallography?
Atoms
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
All of the above
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
d. All of the above
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
All of the above
An icosahedron comprises _ equilateral triangular faces related by _, __, and __ axis of rotational symmetry.
20 ; 5 ; 3 ; 2
