quiz 2

Question 1

FRAP = Fluorescence Recovery After Photobleaching

Answer 1

method for determining movement of proteins by bleaching a pool of molecules in one area and watching the area fill back in (or not)
Lateral diffusion of proteins in cell membrane

Question 2

FRET = Fluorescence Resonance Energy Transfer

Answer 2

method for determining if two proteins are close to one another in cells by exciting a fluoror bound to one and looking for excitation and emission of signal from the other proximity
dependent
without external excitation

Question 3

Specific membrane compartments such ______&_____ as can be isolated from cell lysates by differential centrifugation?

Answer 3

lysosomes and peroxisomes

Question 4

Gel filtration chromatography can seperate

Answer 4

separate proteins based on size/shape

Question 5

____________ have different separation properties that will

cause proteins to interact with them in distinct ways.

Answer 5

column chromatography matrices

Question 6

The structure or conformation of a protein can be predicted

by

Answer 6

NMR, X-Ray crystallography

Question 7

Mass spectrometry

Answer 7

method of determining protein identity and modification proteomics

Question 8

altering gene sequences can be Gene regulatory sequences or protein coding sequences or

Answer 8

(expression change) (gene product change

Question 9

, RISC complex, that also functions in regulating different genes by _____encoded by the genome.

Answer 9

miRNAs

Question 10

Southern Blot :

Northern Blot :

Answer 10

DNA

RNA

Question 11

Proteins can stably associate with membranes by

Answer 11

Hydrophobic transmembrane segments
Posttranslationally added lipid groups that are covalently linked to proteins
Association with other membrane localized proteins

Question 12

Phospholipids that have shorter fatty acid tails or tails which contain unsaturated hydrocarbons cause membranes to be

Answer 12

more fluid

Question 13

When observing the movements of phospholipids in membranes, which of the following occurs least frequently

Answer 13

Movements between the leaflets of a membrane bilayer

Question 14

All transmembrane proteins float and diffuse freely in the bilayer of the plasma membrane in the same manner as phospholipids

Answer 14

false

Question 15

Membrane compartments in eukaryotic cells maintain lipid bilayers whose contents are typically symmetric in their distribution across both leaflets

Answer 15

false

Question 16

Proteins that aid the movement of phospholipids from one leaflet of a membrane bilayer to another are known as

Answer 16

flippses

Question 17

The best way to determine if a protein is able to move in a membrane would be

Answer 17

FRAP

Question 18

3 major phospholipids

Answer 18

Phosphatidylcholine

Phosphatidylethanolamine

Phosphatidylserine

Question 19

Phospholipids rotate….

Answer 19

diffuse and flip flop

Question 20

Membrane fluidity depends on composition and

Answer 20

length of the phospholipid hydrocarbon tails

Question 21

An increase in cholesterol will tend to make membranes:

Answer 21

Stiffer/less permeable

Question 22

Cholesterol and other sterols help control fluidity, filling in spaces between phospholipids and thereby

Answer 22

stiffening the membrane and reducing permeability

Question 23

New membrane phospholipids are first synthesized and inserted into membranes where

Answer 23

The cytosolic surface of the ER

Question 24

Lipid synthesis can only be possilbe with roles of

Answer 24

flippases (cytolsol) and scramblases (cell exterior)

Question 25

Cellular membranes are –_______

and ______also generate and maintain this

Answer 25

asymmetric Flippases

Question 26

Glycolipids and glycoproteins occur only or mainly in

Answer 26

outer leaflet of the plasma membrane

Question 27

3 mechanisms for membrane localization of proteins

Answer 27

Membrane Associated alpha helix or beta sheet Lipid anchor addition Integral Membrane Proteins

Question 28

Membrane spanning proteins are typically extracted from membranes by using

Answer 28

Addition of detergents such as SDS

Question 29

Proteins play major roles in modulating membrane dynamics and organization

Answer 29

flippases fusion catalysts
‘coupling’ proteins for other proteins
diffusion barriers

Question 30

Note: proteins without
sorting signals will
by default remain in

Answer 30

the cytosol