Forces acting across Membranes 1

Question 1

Distribution of water between ECF and ICF

Answer 1

1/3 ECF 2/3 ICF

Question 2

Distribution of water between Plasma and ISF

Answer 2

25% plasma 75% ISF

Question 3

Channel that water freely passes through

Answer 3

Aquaporins

Question 4

What passes freely through all compartments? (2)

Answer 4

Gas and Water

Question 5

Which compartment has the highest K+ conc.

Answer 5

ICF

Question 6

Which compartment has the highest Na+ and Cl- conc.

Answer 6

ECF

Question 7

How are ISF and Plasma different?

Answer 7

Plasma has proteins so higher protein conc.

Question 8

Define varying permeability of membranes

Answer 8

Permeability can increase and decrease at times

Question 9

Why are membranes flexible?

Answer 9

The fatty acids. However if stretched too much, they may rupture.

Question 10

Integral protein structure

Answer 10

Spans the length of the entire membrane

Question 11

Peripheral protein structure

Answer 11

Spans only the phosphate head

Question 12

What are membrane receptors?

Answer 12

Attach from ECF to ICF to allow communication of signals

Question 13

What are membrane transporters?

Answer 13

Integral proteins which allow movement of molecules through a valve-like mechanism (typically for larger molecules (glucose))

Question 14

What are membrane channels?

Answer 14

A type of transporter that can be gated or open (like aquaporins)

Question 15

What are an enzymes role in membrane proteins?

Answer 15

Catalyse reactions on the membrane, on either the outside or inside. Typically convert signals from receptors into a cellular response

Question 16

Structural proteins role in the membrane?

Answer 16

Attach to the cytoskeleton and the ECM to hold the membrane in place and maintain cell shape. Allow 2 cell membranes to stay adjacent to provide a temporary binding site.

Question 17

Glycoproteins role in cell membrane

Answer 17

Cell signalling, cell-cell recognition (recognises self/foreign cell)

Question 18

What drives movement of particles/molecules in a cell

Answer 18

Concentration gradient

Question 19

What is an electrical gradient

Answer 19

The difference in charge across a membrane

Question 20

What is endocytosis?

Answer 20

Macromolecules invaginate a cell membrane to form a vesicle which enters the cell and transport the macromolecules to their final destination

Question 21

What is exocytosis?

Answer 21

A vesicle fuses with the cell membrane, releasing its components to the ECF

Question 22

What is a G protein?

Answer 22

Peripheral proteins found on the inner membrane, responsible for translocate messages for receptor proteins to other proteins on the membrane - e.g. enzymes or ion channels