WK1: STRUCTURE, ORDER, FUNCTION

Question 1

what is molarity?

Answer 1

moles per litre solution

Question 2

what is molality?

Answer 2

moles per kg solvent

Question 3

what is osmolarity?

Answer 3

osmoses per litre solution

Question 4

what is osmolality?

Answer 4

osmoses per kg solvent

Question 5

hypotonic

Answer 5

lower osmotic pressure outside cell

Question 6

hypertonic

Answer 6

higher osmotic pressure outside cell

Question 7

isotonic

Answer 7

equal osmotic pressure inside and outside cell

Question 8

what are the 3 properties of molecules?

Answer 8

hydrophobic, hydrophilic, amphiphilic

Question 9

interstitial fluid

Answer 9

extracellular fluid outside blood vessels

Question 10

plasma

Answer 10

extracellular fluid of blood

Question 11

transcellular fluid

Answer 11

extracellular fluid in spaces e.g. brain ventricles, joint capsules, peritoneal cavity

Question 12

intracellular fluid

Answer 12

water within cells

Question 13

describe the plasma membrane

Answer 13

hydrophobic barrier
lipid soluble molecules can pass freely through lipid bilayer
polar molecules / ions etc. need specific membrane proteins

Question 14

total osmolarity of solution =

Answer 14

sum of osmolality due to each constituents in solution

Question 15

blood plasma osmolality

Answer 15

300 mOsmol kg-1

Question 16

principal ions osmolality

Answer 16

280 mOsmol kg-1

Question 17

glucose/small molecules osmolality

Answer 17

<10

Question 18

proteins osmolality

Answer 18

<1

Question 19

why do proteins have such a low osmolality?

Answer 19

their molecular mass is very high; per gram of protein, the osmotic pressure is lower compared to ions / glucose

Question 20

what is osmotic pressure? what does it depend on?

Answer 20

the minimum pressure needed to prevent inward flow of water across semipermeable membrane. depends on number of particles present not chemical composition.

Question 21

salts osmotic pressure?

Answer 21

2x molar concentration as salts dissociate into constituent ions

Question 22

osmotic pressure equation?

Answer 22

osmotic pressure = MRT

Question 23

osmotic pressure definition?

Answer 23

one gram mole of non-dissociating substance in 1kg of water exerts osmotic pressure of 1 ormolu

Question 24

iso-osmotic

Answer 24

2 solutions are same osmolality; no net pressure as there is same osmotic pressure

Question 25

iso-tonic

Answer 25

no pressure change between intra and extracellular volume. no net fluid movement.

Question 26

if isotonic, then also..

Answer 26

isosmotic. not all isosmotic solutions are isotonic though!

Question 27

why is blood diluted in 0.9% NaCl?

Answer 27

RBCs are surrounded by an isotonic environment (plasma)

Question 28

RBC in isotonic solution?

Answer 28

no change

Question 29

RBC in hypotonic solution?

Answer 29

cell bursts

Question 30

RBC in hypertonic solution?

Answer 30

cell shrivels/crenates