Osmosis DSA

Question 1

Diffusion

Answer 1

a dissolved solute moves from high to low concentration

Question 2

In diffusion, we assume that the solute can/cannot cross the membrane

Answer 2

can

Question 3

If the solute cannot cross the membrane, then what occurs?

Answer 3

Osmosis–> the movement of a solvent (water) down its concentration/pressure gradient

Question 4

how do we equalize a pressure gradient between 2 solutions?

Answer 4

We use the solvent from the less concentrated side to dilute the more concentrated side

Another way to look at this is that the difference in solute concentration creates a concentration gradient for the solvent as well. In this “view”, the more concentrated solution has less solvent, while the more dilute solution has more solvent. Therefore we have a concentration gradient for the solvent to move down.1

Question 5

ICF

ECF

Answer 5

intracellular fluid–> inside the cells

extracellular fluid–> outside the cells

Question 6

in osmosis,

the more concentrated solution will _____ in volume as the solvent moves from the _____ concentrated solution to balance them

Answer 6

increase

less

Question 7

thus, osmosis produces big changes in ______

Answer 7

volume

Question 8

When water moves into a cell, it _____

Answer 8

swells

Question 9

when water moves out of a cell, it will ______

Answer 9

shrink (crenate)

Question 10

the differences between the ICF and ECF are made and maintained by

Answer 10

1. the semi-permeable membrane

2. presence of active transporters (Na/K ATPase pumps) that moves things against their concentration gradient.

Question 11

What is the osmolarity of the ICF and ECF

Answer 11

The osmolarity of the ICF and ECF are the same (290 mOsm). Despite the differences in ion concentrations, the osmolarity is the same and we have no gradient that would make ocsmosis occur.

Question 12

Does osmosis depend on the concentration of the solutes?

Answer 12

No. Osmosis does not depend on the concentration of the solutes.

Osmosis only occurs if there is a gradient for water.

Question 13

Why doesnt osmosis happen in the body

Answer 13

Osmosis does not care about gradients for solutes.

It only depends on gradients of water. Thus, even though there are concentration gradients for particular solutes, there is an even amount of total solutes on ICF and ECF sides so osmosis is not occuring

Question 14

hypotonic

Answer 14

alot of water

less solutes

Question 15

K+ permeability across the membrane

Answer 15

high

Question 16

why does K+ have a high permeability?

Answer 16

there are K+ channels present on the membrane

these are open most of the time

Question 17

Why does Cl- have a high permeability

Answer 17

cell also have Cl- channels that are open most of the time

Question 18

why does bicarb have high permeability

Answer 18

because it easily converts to CO2 and back to bicarb

thus, its permeability is due to CO2s ability to cross the membrane

Question 19

Na
Cl
Ca2+
bicarb

have higher concentrations in the ____

Answer 19

ECF