Membrane / Signal Transduction - w4

Question 1

What three thing affect the fluidity of the plasma membrane?

Answer 1

temperature, cholesterol, and fatty acid saturation

Question 2

What two phospholipids reside in the inner leaflet?

Answer 2

phosphatidylserine and phosphatidylethanolamine

Question 3

What do lipid rafts consist of?

Answer 3

cholesterol, sphingolipids, phospholipids, and protein receptors

Question 4

What molecules make up the outer leaflet of the membrane?

Answer 4

phosphatidylcholine and spingomyelin

Question 5

What type of fatty acids allow for more little corners for more molecules to pass through?

Answer 5

unsaturated fatty acids

Question 6

What is the main substance that adds stability to the membrane?

Answer 6

cholesterol

Question 7

What moves to the external leaflet when there is apoptotic cell death?

Answer 7

phosphatidylserine

Question 8

What are the three types of plasma membrane proteins?

Answer 8

integral (span the membrane), peripheral membrane proteins, and lipid anchored proteins

Question 9

Which plasma membrane protein is bound to polar lipid heads or integral proteins and can be removed by ionic solvents?

Answer 9

peripheral membrane proteins

Question 10

Which plasma membrane protein is bound to either leaflets by a covalently attached lipid group?

Answer 10

lipid-anchored proteins

Question 11

Which lipid-anchored protein is bound to the inner leaflet?

Answer 11

g-proteins

Question 12

What are extracellular carbohydrates that are covalently linked to lipids (glycolipids) or proteins (glycoproteins)?

Answer 12

glycocalyx

Question 13

What is the glycocalyx important for?

Answer 13

cell to cell recognition

Question 14

What are heavily glycosylated integral proteins that provide a negative charge?

Answer 14

glycophorins

Question 15

What is the most abundant membrane protein in RBC and regulations anion exchange?

Answer 15

Band 3

Question 16

What peripheral proteins are bound to Band 3 and glycophorins?

Answer 16

ankyrin and 4.1

Question 17

What are two cytoskeletal proteins in the RBC?

Answer 17

spectrin and actin

Question 18

What acid gives RBC a negative charge?

Answer 18

sealic acid

Question 19

What do we call RBC death?

Answer 19

senescence

Question 20

What is the movement down a concentration gradient via channel or carrier proteins?

Answer 20

facilitated diffusion

Question 21

What is the movement against the concentration gradient with the help of ATP?

Answer 21

active transport

Question 22

What is the transport molecule that regulates the passage of water?

Answer 22

aquaporins

Question 23

What type of transport takes glucose (along with Na+) into intestinal cells?

Answer 23

secondary active transport by (SGLT)

Question 24

What are the uniport transporters that diffuse glucose into the blood stream?

Answer 24

GLUT

Question 25

What type of transport is in the process of releasing glucose from the blood into the cells?

Answer 25

facilitated diffusion

Question 26

What causes cystic fibrosis?

Answer 26

defective Cl- channel (Cystic Fibrosis Transmembrane-conductance Regulator)

Question 27

What happens in Cl- channels in cystic fibrosis?

Answer 27

ATP phosphorylation does not occur to cause conformational change and opening of channel

Question 28

This reduced Cl- secretion in CF causes what in the airways?

Answer 28

thickening of fluid and mucus

Question 29

As digoxin inhibits Na+/K+ ATPase in heart muscles what happens?

Answer 29

increase of intracellular Na+ , causing increase of intracellular Ca2+

Question 30

What type of hormones attach to cell-surface receptors?

Answer 30

water-soluble

Question 31

What is a main example of an intracellular receptor?

Answer 31

steroid hormone receptors

Question 32

How are ion channels activated?

Answer 32

due to a conformational change on ligand binding

Question 33

What type of receptor has an intracellular domain that gets activated with a ligand binds to extracellular domain?

Answer 33

kinase / kinase-binding receptors

Question 34

What do we call dimers phosphorylating other dimers?

Answer 34

autophosphorylation

Question 35

Which receptor is heptahelical and is most common of membrane receptors?

Answer 35

G-protein coupled receptors

Question 36

How do G-protein receptors initiate signals?

Answer 36

through heterotrimeric G-proteins (a, B, Y)

Question 37

The heterotrimeric activates an enzyme that generates what?

Answer 37

secondary members (cAMP, DAG, IP3)

Question 38

What are the four ways that signals can be terminated?

Answer 38

1. degradation of the messenger itself
2. downregulation or desensitization of receptors
3. GTPases and protein phosphatases (dephosphorylation)
4. degradation of secondary messengers)