Homeostasis 2

Question 1

What does RVD stand for?

Answer 1

Regulatory Volume Decrease

Question 2

What does RVI stand for?

Answer 2

Regulatory Volume Increase

Question 3

What does hypotonic mean?

Answer 3

Lower osmotic pressure - more water

Question 4

What does hypertonic mean?

Answer 4

Higher osmotic pressure - less water

Question 5

What conditions lead to RVD?

Answer 5

Hypo out, hyper in

Question 6

What conditions lead to RVI?

Answer 6

Hyper out, hypo in

Question 7

What occurs during RVD?

Answer 7

Loss of ions and solute and water

Question 8

What occurs during RVI?

Answer 8

Gain of ions and solute and water

Question 9

Breifly outline RVD.

Answer 9

Hypo out - more water out - water moves in - loss of ions/solute/water - decrease in volume

Question 10

Briefly outline RVI.

Answer 10

Hyper out - less water out - water moves out - gain of ions/solute/water - increase in volume

Question 11

What does SACs stand for?

Answer 11

Stretch activated Ca channels

Question 12

What do SACs do?

Answer 12

Increase IC Ca when cell stretched

Question 13

What ions leave during RVD?

Answer 13

K, Cl and a/a

Question 14

What does SACCs stand for?

Answer 14

Shrinkage-activated cation channels

Question 15

What are SACs involved in?

Answer 15

RVD

Question 16

What are SACCs involved in?

Answer 16

RVI

Question 17

What do SACCs do?

Answer 17

Increase IC Ca when cell shrinks

Question 18

What is the difference between SAC and SACC function?

Answer 18

Difference in stimulus, and location, but same mechanism

Question 19

What ions move in during RVI?

Answer 19

Na, K, Cl

Question 20

What is hyponatraemia?

Answer 20

Low Na

Question 21

What is the role of RVD in hyponatraemia?

Answer 21

Hypo out - more water out - water moves into braincells - RVD counters

Question 22

What three methods do cells employ to maintain pH?

Answer 22

Buffering, acid extrusion, acid loading

Question 23

What controls acid extrusion from the cell?

Answer 23

Na/H exchanger

Question 24

What controls acid loading into the cell?

Answer 24

Cl/HCO3 exchanger

Question 25

Name two buffers

Answer 25

HCO3 and NH2

Question 26

How does HCO3 buffer?

Answer 26

pHi increase = dissociation into HCO3- and H+

Question 27

How does NH2 buffer?

Answer 27

pHi decrease = association into NH3+

Question 28

What does Na/H exchanger, and thus acid extrusion, depend upon?

Answer 28

Na gradient set up bu ATPase

Question 29

What are the three advantages of the eukaryotic secretory system?

Answer 29

Allows assmbly of multi-unit complexes, obviates the need for the cell-wall, regulation of secretion and endocytosis

Question 30

Name a chaperone in the ER than ensures proper folding.

Answer 30

BiP

Question 31

Name three ER folding diseases.

Answer 31

CF, emphysema, hypothyroidism

Question 32

How is emphysema an ER folding disease?

Answer 32

Deficiency of secretion of alpha-1-trypsin

Question 33

How is hypothyroidism an ER folding disease?

Answer 33

Production of mutant thyroglobulin = proliferation of ER to try and secrete the correct amount

Question 34

Name three coated vesicle types.

Answer 34

COP I, COP II, clathrin

Question 35

Where (generally) is COP I?

Answer 35

ER

Question 36

Where (generally) is COP II?

Answer 36

Golgi

Question 37

Where (generally) is clathrin?

Answer 37

PM-Golgi

Question 38

What are the three steps in COP II vesicle formation?

Answer 38

Recruit Sar 21, recruit Sec 23/24 - content recognition, recruit Sec 13/31

Question 39

What does GEF stand for?

Answer 39

Guanine exchange factor

Question 40

What does GAP stand for?

Answer 40

Guanine activation factor

Question 41

What do GEFs do?

Answer 41

Activate GDP - NOT BY PHOSPHORYLATION

Question 42

What do GAPs do?

Answer 42

Deactivate GTP - BY PHOSPHORYLATION

Question 43

What are mutant GTPases good for?

Answer 43

Probing membrane traffic

Question 44

What does injection of dominant negative Sar1 cause?

Answer 44

Accumulation of resident golgi protein in ER

Question 45

How does Sar1GDP act as dmoinant negative?

Answer 45

Sequestering GEFs

Question 46

What GTPase does COP I utilise?

Answer 46

Sar 1

Question 47

What GTPase does COPII utilise?

Answer 47

Arf 1

Question 48

What GTPases does clathrin utilise?

Answer 48

Arf 1 and others unknown

Question 49

What cargo does COP I carry?

Answer 49

Newly synthesised proteins

Question 50

What cargo does COP II carry?

Answer 50

Retrieved and newly synthesised proteins

Question 51

What cargo does clathrin carry?

Answer 51

Lysosomal proteins, regulated secretory proteins and endocytosed material

Question 52

What does COP I mediate?

Answer 52

Antero and retrograde transport through the golgi

Question 53

Describe the COP I coat.

Answer 53

Complex of seven polypeptides

Question 54

What do SNAREs contribute to?

Answer 54

Fidelity of membrane transport, catalysis of membrane fusion

Question 55

What do SNAREs do?

Answer 55

Create docking site for vesicle

Question 56

What happens to SNAREs during docking?

Answer 56

t-SNARE binds v-SNARE

Question 57

What happens to SNAREs after docking?

Answer 57

Must be seperated again by adaptor proteins, NSF and ATP

Question 58

What makes the clathrin lattice?

Answer 58

Clathrin triskelia polymerase

Question 59

What allows us to determine where proteins are localised in living cells?

Answer 59

Immunofluorescance

Question 60

What links cargo to the clathrin lattice?

Answer 60

AP2

Question 61

What is the function of the early endosome?

Answer 61

Major endocytic sorting station

Question 62

What facilitates sorting in the early endosome?

Answer 62

Reduced pH

Question 63

How long does it take for cargo to reach the early endosome?

Answer 63

5-10 minutes

Question 64

What targets cargo to late endosomes?

Answer 64

Ubiquitination

Question 65

What is ubiquitination?

Answer 65

Reversible post-translational modification

Question 66

Characterise receptor mediated uptake

Answer 66

Saturable