Lab- Diffusion and Osmosis

Question 1

Brownian Movements

Answer 1

erratic, nondirectional, zigzag pathways

Question 2

diffusion

Answer 2

net movement of molecules/ions from areas of high concentration to low concentration

Question 3

permeability

Answer 3

a measure of how easily the molecules of a substance can pass through a membrane

Question 4

3 characteristics of molecules that affect permeability of plasma membranes to those molecules

Answer 4

1. size of the molecule
2. the charge/polarity of the molecule (the more polar a molecule is, the less permeable a plasma membrane would be
3. the shape of the molecule

Question 5

aquaporins

Answer 5

special channels for water. have a small opening of about 7 angstroms

Question 6

semipermeable membrane

Answer 6

a membrane with aquaporins. Called semipermeable b/c water can diffuse through, but bigger molecules like proteins and sugars cannot

Question 7

molarity

Answer 7

concentration based on number of molecules in a solution

Question 8

osmolarity

Answer 8

a measure of concentration that is based on the total number of particles of all types of solution

Question 9

how to calculate osmolarity?

Answer 9

M x ions diss. = osm.

Question 10

what drives the osmosis of water?

Answer 10

-the differences in osmolarity across a membrane
-water moves towards areas with higher osmolarity

Question 11

what’s the osmolarity of intracellular fluids in our cells?

Answer 11

0.3 osmolar

Question 12

crenation

Answer 12

the shrinking of shriveling of cells due to the loss of water

Question 13

hemolysis

Answer 13

when red blood cells burst

Question 14

what determines rate of osmosis?

Answer 14

by measuring the amount of time it takes for hemolysis of red blood cells to occur

Question 15

what leads to a more rapid movement of water due to osmosis?

Answer 15

a great concentration gradient

Question 16

where to physiological processes occur?

Answer 16

aqueous solutions

Question 17

how does temperature affect the rate of molecular movement?

Answer 17

faster movement with a higher temperature

Question 18

why was the time to hemolysis different for urea, ethylene glycol, thiourea, and glycerol?

Answer 18

molecular size differed between the solutions, as well as molecular shape which affected hemolysis time.

Question 19

why does 0.3 osm/L cause hemolysis?

Answer 19

urea diffuses into the cell, so osmolarity increases. then water goes into the cell!!!