Osmosis

Question 1

What is the definition of osmosis

Answer 1

Diffusion of water molecules across a partially permeable membrane from an area of high water potential to an area of lower water potential

Question 2

What is water potential

Answer 2

The likelihood of water molecules to diffuse out of or into a solution

Question 3

What has the highest water potential and what does isotonic mean

Answer 3

Pure water

Two solutions with the same water potential

Question 4

What factors affect water potential and why do they affect it

Answer 4

Water potential gradient- higher the water potential gradient the faster the rate of osmosis
Thickness of exchange surface - Thinner the exchange surface the faster the rate of osmosis
Surface area of exchange surface -the larger the surface area the faster the rate of diffusion

Question 5

What happens to the water potential gradient as osmosis takes place

Answer 5

The difference on water potential on either side of the membrane decreases so rate of osmosis levels off over time

Question 6

What does the point at which the curve crosses the x axis mean

Answer 6

Point at which the water potential of sucrose Soloution is the same as the water potential of the potato cells

Question 7

What is the experiment of water potential using potato chips

Answer 7

1)Use cork borer to cut Potatoes into identically sized chips 1cm in diameter
2)Divide chips into groups of 3 and measure mass of each group using mass balance
3)Place one group into each of the sucrose solution
4)Leave chips in solution for at least 20 minutes
3)Remove chips and pardy with paper towel to removes access water
6)Weigh each group again and record results
7)Calculate change in mass to reach group
8)Use resulte to make calibration curve showing change in mass against sucrose solution

Question 8

How do you make serial dilution

Answer 8

1)line 5 test tubes in a test tube rack
1)Add 10cm3 of 2M sucrose solution to fint test tube then 5cm3 of distilled water to other 4
test tubes
3)Using a pipette draw 5cm3 of solution from first test tube add it to distilled water in second test tube and mix the solution thoroughly
↳ This is half as concentrated as the fint solutions IM
4)Repeat process till you get 0.5M ,0. 25M&0. 125M