Exam Review

Question 1

phospholipids spin and diffuse ______ within the plane of the membrane

Answer 1

laterally

Question 2

how do we measure lateral diffusion?

Answer 2

FRAP

Question 3

FRAP stands for?

Answer 3

fluorescence recovery after photo bleaching

Question 4

FRET stands for?

Answer 4

Forster resonance energy transfe

Question 5

describe FRAP

Answer 5

Start with fluorochrome such as GFP tagged transmembrane, uses a high intensity light to bleach the GFP in certain patch of membrane until it no longer fluoresces,
if proteins are moving the bleached and unbleached proteins will exchange positions over time

Question 6

describe FRET

Answer 6

measure distance between fluorochromes, requires a pair of fluorescent proteins where emission wavelength of first is near the excitation wavelength of the second, efficiency of this energy transfer is proportional to the distance between fluorochromes, fret reveals protein interactions

Question 7

the cytosolic face always faces the ______

Answer 7

cytoplasm

Question 8

the exoplasmic face always faces the ______ ______ or _____ ______

Answer 8

cellular exterior, interior lumen

Question 9

what is the orientation of phospholipids?

Answer 9

hydrophilic water loving head toward a membrane surface and its hydrophobic water hating tail toward the membrane interior

Question 10

what are the 3 sterols?

Answer 10

cholesterol, ergosterol and stigmasterol

Question 11

where are phospholipids synthesized?

Answer 11

cytosolic face of endoplasmic reticulum

Question 12

a phospholipid is found in the exoplasmic face of plasma membrane during _____ _______ and requires _______?

Answer 12

lipid trafficking and requires flippases

Question 13

sphingomylein is synthesized on the exoplasmic face of __________

Answer 13

golgi complex

Question 14

positivel charged ___ and ____ residues near the cytosolic side of the helix binds negatively charged phospholipid head groups as the anchor

Answer 14

Arg and Lys

Question 15

cytosolic and exoplasmic domains are ______

Answer 15

hydrophilic

Question 16

detergents are ________

Answer 16

ampipathic

Question 17

the rate of diffusion across a pure phospholipid barrier is proportional to _____, _______ and _______

Answer 17

[ ] , hydrophobicity and size

Question 18

synthesis od secreted proteins, integral plasma membrane proteins and proteins destined for the ER begin on ________ faces

Answer 18

cytosolic

Question 19

secreted protein s must be brought to the _______

Answer 19

ER lumen

Question 20

most phospholipids are synthesized on the _________ but assembled on the _______

Answer 20

smooth ER, rough ER

Question 21

tail anchored proteins are recognized by ?

Answer 21

Get3

Question 22

during transport to the mitochondria the matrix targeting sequence is located at the _____ terminus

Answer 22

N

Question 23

the nucleus is separated from the cytoplasm by what two membranes?

Answer 23

nuclear envelop, continuous with the ER

Question 24

______ allows movement of mRNAs, tRNAs, ribosomal subunits out of the nucleus

Answer 24

nuclear pores

Question 25

import of nuclear proteins requires ________ signals

Answer 25

localization

Question 26

NLS directs _______ transport into the nucleus

Answer 26

selective

Question 27

all nuclear proteins are synthesized in the _______ and then imported

Answer 27

cytoplasm

Question 28

what is Ran

Answer 28

monomeric G protein

Question 29

nuclear transport receptor bind to ____ on cargo proteins and FG repeats on nucleoporins

Answer 29

NLS

Question 30

what are the 3 mechanisms for nuclear import of proteins?

Answer 30

cytoplasm, nucleoplasm, system recycling

Question 31

nuclear export can either be Ran _________ or Ran __________

Answer 31

dependent or independent

Question 32

what is the secretory pathway of protein sorting?

Answer 32

distribution of soluble and membrane proteins, synthesized by the rough ER to final destinations at the cell surface or in lysosomes

Question 33

what is the endocytic pathway of protein sorting?

Answer 33

Vesicles budding from the plasma membrane take up soluble extracellular proteins and deliver them to lysosomes via late endosomes

Question 34

what is vesicle budding initiated by?

Answer 34

recruitment of GTP binding proteins to a patch of donor membrane

Question 35

vesicle budding is driven by?

Answer 35

polymerization of soluble protein complexes on the cytosolic face of the membrane, form proteinaceous vesicle coat

Question 36

during vesicle budding Rab GTP is hydrolyzed to _______

Answer 36

Rab GDP

Question 37

what are the three types of coated vesicles?

Answer 37

COPII, COPI, Clathrin

Question 38

all vesicles contain small _____ binding proteins that control coat assembly

Answer 38

GTP

Question 39

____ protein is in COPI and clathrin coated vesicles

Answer 39

ARF

Question 40

___ protein is in COPII vesicles

Answer 40

Sar1

Question 41

what is the role of Sar1 GTP?

Answer 41

directs coat proteins into place

Question 42

what occurs after GTP hydrolysis during vessicle coat assembly?

Answer 42

Sar1 GDP undergoes a conformational change and causes disassembly of the coat

Question 43

what are the 4 GTPase switch proteins?

Answer 43

ARF, Sar1, Ran, Rab

Question 44

early stages of the secretory pathway moves in the | ______ direction

Answer 44

anterograde

Question 45

what are the five destinations from the trans golgi network?

Answer 45

1. COPI vesicles 2. AP3 complex vesicles 3. Clathrin coated vesicles 4. constitutive secretory vesicles 5. regulated secretory vesicles

Question 46

clathrin coated vesicles have two layers consiting of what?

Answer 46

1. outer layer of fibrous protein clathrin | 2. inner layer composed of adapter protein AP complex

Question 47

______ pinches off clathrin coated vesicles

Answer 47

dynamin