Forces Across Membranes 3

Question 1

What is osmosis?

Answer 1

Net movement of water from regions of high concentration to regions of low concentrations

Question 2

What is diffusion?

Answer 2

Net movement of solute from regions of high concentration to regions of low concentration

Question 3

How does the body maintain osmotic equilbrium?

Answer 3

By water moving freely between the ECF and ICF

Question 4

What relationship does the concentration of H₂O have to the concentration of solute?

Answer 4

Inversely related, the more solute particles the more they displace water

Question 5

What must the concentration and volume of water and solute of a membrane permeable to both be?

Answer 5

The same

Question 6

In terms of volume and water, how are they different across a membrane if it is only permeable to water and not the solute?

Answer 6

The same concentration of water on either side but a different volume

Question 7

What is osmotic pressure?

Answer 7

Pressure that must be applied to stop osmotic movement

Question 8

What is concentration expressed as?

Answer 8

mol/L

Question 9

How many molecules are in 1 mol

Answer 9

6.02x10²³ molecules

Question 10

What does a concentration of 1M mean?

Answer 10

Concentration of 1 mol/L

Question 11

What determines the osmotic effect of water (particles or molecules)?

Answer 11

The number of particicles, for example:

1 mole of glucose added to 1L of water reduces [H₂O] by 1 mole/L

1 mole of NaCl added to 1L of water reduces [H₂O] by 2 mole/L

Question 12

What is osmolarity?

Answer 12

Measure of concentration of biological solutions in units of Osmoles

Question 14

What is osmole?

Answer 14

Describes the number of particles per L of solution

Question 15

Give examples of the use of Osmole as a unit?

Answer 15

1M solution of glucose has an osmolarity of 1osmol/L

1M of NaCl has an osmolarity of 2osmol/L

Question 16

What does normal plasma have an osmolarity of and how does this compare to within cells?

Answer 16

285mOsmol/L, which is the same within cells

Question 17

What does osmolarity not describe which is important?

Answer 17

The nature of the particles (if they can cross the membrane)

Question 18

What does osmolarity describe?

Answer 18

The number of particles in solution

Question 19

What happens to water when the concentration of a solute which cannot pass the membrane changes?

Answer 19

Change in concentration creates an osmotic flux which causes a net movemet of water

Question 20

What does a net movement of water cause?

Answer 20

A change in volume

Question 21

What is the volume of a cell dependent on?

Answer 21

The concentration of non penetrating solutes on either side of the membrane

Question 22

What is osmolarity?

Answer 22

Describes the total number of particles in solution

Question 23

What is tonicity?

Answer 23

Describes the total number of non penetrating particles in solution

Question 24

What definitions do osmolarity use?

Answer 24

Isometric

Hypoosmotic

Hyperosmotic

Question 25

What does isometric mean?

Answer 25

Same total number of solute particles as ECF)

Question 26

What does hypoosmotic mean?

Answer 26

Fewer total number of solute particles

Question 27

What does hyperosmotic mean?

Answer 27

Greater total of solute particles than ECF

Question 28

What definitions does tonicity use?

Answer 28

Isotonic Hypotonic Hypertonic

Question 29

What does isotonic mean?

Answer 29

Same number of non penetrating solute particles as normal ECF

Question 30

What does hypotonic mean?

Answer 30

Few number of non penetrating particles than ECF

Question 31

What does hypertonic mean?

Answer 31

Greater number of non penetrating solute particles than ECF

Question 32

What happens to cells in a hypotonic solution?

Answer 32

Swell as water moves down the chemical gradient into the cell

Question 33

What happens to cells in a hypertonic solution?

Answer 33

Shrink as water moves down the chemical gradient out of the cell

Question 34

What is intravascular haemolysis?

Answer 34

Cells bursting, which can kill due to introducing proteins in the ECF increasing the tonicity