Transport Through Membranes

Question 1

Name the 3 body fluid compartments and what they’re seperated by

Answer 1

Plasma(blood)

Leaky epithelium (capillary) Barrier

Interstitial fluid

Plasma membrane barrier

Intracellular fluid

Question 2

What molecules are let through the plasma into the interstitial space through pores in leaky epithelium

Answer 2

Small molecules such as ions

No large molecules like proteins or red blood cells

Question 3

Which body fluid has no proteins in it

Answer 3

The interstitial fluid

Question 4

Where are the most ions exchanged located

Answer 4

Extracellular fluid. Intracellular fluid has very low concentration of ions

Question 5

What is the difference in ion composition between extracellular and intracellular called

Answer 5

Chemical disequilibrium

Question 6

What 2 things cause chemical disequilibrium

Answer 6

There is active transport of NA out of the intracellular space (for active transport)

The plasma membrane is a barrier to ions passing due to them being polar

Question 7

What moves freely in all 3 body fluids

Answer 7

Water , moves via osmosis across all 3 membranes

Question 8

What is meant by solution solvent and solute

Answer 8

Solvent is water usually

Solute is eg glucose (makes something concentrated)

Solution is the mix

Question 9

All compartments have 300 mOSM. This means they’re in a state of osmatic equilibrium. What is another word for this

Answer 9

Isosmotic

Question 10

What is osmolarity

Answer 10

Number of the particles eg glucose per volume (L) of solution

Question 11

How do you calculate osmolarity

Answer 11

Molar concentration x number of particles

Eg naCl = 2 particles

1M x 2 = 2 osm

Question 12

How do you go from mOSM to osm

Answer 12

/ by 1000

Question 13

What happens to osmolarity if there is increase in molecules/ions

Answer 13

The osm goes up (as conc goes up)

Question 14

Where does water move

Answer 14

From low OSM (low conc) to high OSM (high conc)

Question 15

What happens in terms of osmolarity when you drink water when you sweat (lose salt and water)

Answer 15

The ecf decreases in OSM (dilution of ions) this means water moves out of the ecf into the intracellular space which is bad

Question 16

What events occur when you get extra intake or ions eg na Cl when eating

Answer 16

There is increase in ions in ECF. This will increase the OSM. This causes water to move out of the intracellular fluid

Causing signal to the thirst centre

Question 17

The intracellular space has many organic solutes such as amino acids, proteins, sugars. What does this attract that contributes to its OSM

Answer 17

Counterions

This would increase the OSM (high concentration)

Question 18

How does the icf counteract the high osm due to counterions and how is this dangerous

Answer 18

A lot of water is drawn in

This can be dangerous and cell could burst

Question 19

What does the icf naturally large osm get solved by

Answer 19

Actively pumping Na+ out of cell (3) 
And K (2) into cell 

This causes a chemical disequilibrium

Decreases the HIGH OSM

Question 20

Explain the process of the na+ k pump

Answer 20

3 na will bind to the active site and 2 k will bind

Atp ase hydrolyses atp into adp. Causes conformational change. This causes movement of na out of cell and k into cell

Question 21

What are transport proteins called that only transport 1 molecule

Answer 21

Uniporter

Eg GLUT 4

Question 22

What does primary active transport mean

Answer 22

The process in which energy ADP is generated through hydrolysis and also a chemical disequilibrium

Via the k/na ATPase system

Question 23

How does primary active transport allow secondary active transport

Answer 23

Secondary AT uses the gradient of ions produced by primary AT eg in co transport

Question 24

What is the co transport protein called that moves 2 molecules into same direction (down conc gradient)

Answer 24

Symporter

Question 25

What is the co transporter that transport 2 molecules in different directions called. And give example

Answer 25

Anti Porter

Eg calcium/na anti Porter

Calcium moves out and Na moves in

Question 26

Give examples or 3 primary active transporters

Answer 26

Na/k ATPase (anti Port)

Ca2+ ATPase

H+ ATPase (proton pump)