Membrane Structure/Transport

Question 1

A sphere vesicle with at least one lipid bilayer is called…

Answer 1

liposome

Question 2

What are glycerophospholipids named according to?

Answer 2

The alcohol group attached to the phosphate in the polar head.

Question 3

What are the four components glycerol phosopholipid?

Answer 3

Fatty acid chains (2), glycerol, phosphate and amino alcohol

Question 4

What is the difference between sphingosine and ceramide?

Answer 4

Fatty acid chain bound to the amine group

Question 5

What amino alcohol group does sphingomyelin have?

Answer 5

Choline

Question 6

What is sphingomyelin derived from?

Answer 6

Ceramide

Question 7

Where does ceramide become sphingomyelin?

Answer 7

Golgi apparatus

Question 8

Which leaflet is phosphatidylethanolamine mostly found?

Answer 8

Inner

Question 9

Which leaflet is phosphotidylserine mostly found?

Answer 9

Inner

Question 10

Which leaflet is phosphatidylinositol mostly found?

Answer 10

Inner

Question 11

Which leaflet is phosphatidylcholine mostly found?

Answer 11

Outer

Question 12

Which leaflet is spingomyelin mostly found?

Answer 12

Outer

Question 13

Which leaflet are glycolipids mostly found?

Answer 13

Outer

Question 14

Which membrane contains a high occurrence of cardiolipin?

Answer 14

Mitochondrial (inner) membrane

Question 15

Factors affecting membrane fluidity (4)

Answer 15

1. Temperature
2. Cholesterol level
3. Saturation of fatty acyl chains
4. fatty acyl chain length

Question 16

How does high temperatures affect membrane fluidity?

Answer 16

As temperature increases, the membrane becomes more fluid

Question 17

Effect of cholesterol on membrane fluidity?

Answer 17

When temperature is low, it keeps it fluid. At high temperatures, it keeps it from becoming too fluid. Really dope yo

Question 18

Does fatty acyl chain saturation make the membrane more or less fluid?

Answer 18

Less

Question 19

True or false: longer fatty acyl chains make the membrane more fluid?

Answer 19

False

Question 20

What is a lipid raft?

Answer 20

Area of densely packed lipids.

Question 21

Protein mobility on a lipid raft?

Answer 21

Decreased.

Question 22

What do flippases and floppases require to work?

Answer 22

ATP

Question 23

True of false: scramblase requires energy?

Answer 23

False.

Question 24

Does flippase move proteins from in to out or out to in?

Answer 24

Out to in.

Question 25

Does floppase move proteins from in to out or out to in?

Answer 25

In to out.

Question 26

What increases the activity of scramblases?

Answer 26

Ca2+

Question 27

Where does phospholipid synthesis occur?

Answer 27

Cytosolic surface of the ER

Question 28

Where do glycolipids get their precursors?

Answer 28

Golgi apparatus

Question 29

Which phospholipid acts as a signal for apoptosis and cell senescence on the extracellular leaflet?

Answer 29

Phosphatidylserine

Question 30

What is a common extracellular protein anchor?

Answer 30

Glycosylphosphatidylinositol

Question 31

Acyl anchors are used for...

Answer 31

cytoplasmic face peripheral protein anchoring

Question 32

Thioester bonds are used on which leaflet

Answer 32

cytosolic

Question 33

GPI-anchored proteins are involved with signal transduction in what membrane structure?

Answer 33

Lipid rafts

Question 34

Fick's Law of Diffusion

Answer 34

(surface area) (concentration gradient) (membrane permeability) / membrane thickness

Question 35

What group lines the selectivity filter of a K+ channel?

Answer 35

C=0 (carbonyl)

Question 36

What is a less selective ion channel called which allows both Sodium and Potassium to pass?

Answer 36

monovalent cation channel

Question 37

What is a competitive inhibitor of glucose channels?

Answer 37

Galactose

Question 38

Location of GLUT1 transporter?

Answer 38

Most cells; RBCs; endothelial cells esp in BBB. (Km 1-2 mM)

Question 39

Location of GLUT2 transporter?

Answer 39

Pancreatic beta cells; liver. REVERSIBLE | Km = 15-20 mM

Question 40

Location of GLUT3 transporter?

Answer 40

Neurons (Km = 1mM)

Question 41

Location of GLUT4 transporter?

Answer 41

Skeletal muscles and fat cells. Insulin sensitive. (Km=5 mM)

Question 42

What is the kinetic effect of insulin on GLUT4?

Answer 42

It increases Vmax (by way of exocytosing more receptors)

Question 43

What is SGLT1?

Answer 43

Na+/glucose contransporter (symporter) found in the small intestine and kidneys

Question 44

How many sodium ions are cotransported with glucose in SGLT1?

Answer 44

2

Question 45

Where is the chloride-bicarbonate exchanger?

Answer 45

Erythrocytes

Question 46

What type of transporter is the chloride-bicarbonate exchanger? Symporter or antiporter?

Answer 46

Antiporter

Question 47

What is significant about the Cl/HCO3 exchange?

Answer 47

electrochemically neutral

Question 48

What are the four classes of ATP-powered pumps?

Answer 48

P-Class, V-Class, F-Class, ABC

Question 49

Which type of ATP-Powered pump is reversibly phosphorylated?

Answer 49

P-Class

Question 50

Structure of P-Class pumps?

Answer 50

two alpha subunits

Question 51

What type of pump is Na/K ATPase?

Answer 51

P-class

Question 52

Is the E1 conformation of Na/K ATPase facing the cytosol or extracellular space?

Answer 52

Cytosol

Question 53

Is the E2 conformation of Na/K ATPase facing the cytosol or extracellular space?

Answer 53

Extracellular

Question 54

What are the two Na/K ATPase inhibitors we learned?

Answer 54

Digoxin and Oubain

Question 55

What is digoxin used to treat, besides its inhibitor function?

Answer 55

Heart failure

Question 56

The V-class proton pumps work in which direction?

Answer 56

Cytosol to intracellular organelles

Question 57

How do V-class proton pumps work?

Answer 57

Use ATP hydrolysis to pump H+ against its electrochemical gradient

Question 58

How do F-class proton pumps work?

Answer 58

Pump H+ along its electrochemical gradient to form ATP from ADP + Pi

Question 59

What organelles are V-class pumps important for?

Answer 59

Lysosomes and endosomes (keeping the pH low)

Question 60

Structure of ABC transporters

Answer 60

Two transmembrane domains. Two nucleotide binding domains

Question 61

Are most ABC transporters exporters or importers in eukaryotes?

Answer 61

Exporters

Question 62

Multidrug resistant transporters are what type of transporter?

Answer 62

ABC transporter