Required Practical 3

Question 1

What is a calibration curve?

Answer 1

A calibration curve is a graph used to find an unknown concentration of a sample by comparing the unknown to a set of standard samples with known concentrations

Question 2

In this practical, what is the calibration curve used for?

Answer 2

The calibration curve is used to determine the water potential in a potato tissue

Question 2

What is osmosis?

Answer 2

Osmosis is the net movement of water across selectively permeable membrane from a high to low water potential

Question 3

What is water potential?

Answer 3

Water potential is the relative tendency of water to move from one place to another, which is determined by the solute’s concentration

Question 4

What does a high solute concentration mean for the water potential and moveability?

Answer 4

If there is a high solute concentration, there is a higher water potential and the water is more likely to move from one place to another

Question 5

What is the conclusion of the required practical?

Answer 5

Potato chips in lower concentrations of glucose solution will increase in mass, whilst those in the higher concentrations of glucose solution will decrease in mass

Question 6

Why do the potato chips in the dilute glucose solutions increase in mass?

Answer 6

In the dilute glucose solutions, the solution has a higher water potential than the potato, so water passively moves via osmosis to the area of lower water potential. This causes the potato to increase in mass

Question 7

Why do the potato chips in the concentrated glucose solutions decrease in mass?

Answer 7

In concentrated glucose solutions, water will move out of the potato, thus the potato will decrease in mass