Required practical 3

Question 1

What is osmosis?

Answer 1

The movement of water from an area of high water potential to an area of low water potential across a partially permeable membrane.

Question 2

What water potential is pure water?

Answer 2

0

Question 3

What do isotonic, hypotonic, and hypertonic mean?

Answer 3

Isotonic is when the water potential is the same in both cell and solution.
Hypotonic is when water potential is more positive (less concentrated) in the solution than inside the cell.
Hypertonic is when water potential is more negative (more concentrated) in the solution than inside the cell.

Question 4

What is the difference when both animal and plant cells are placed in hypotonic solutions?

Answer 4

Animal cells will burst, however, plant cells because they have strengthened cell walls will become turgid.

Question 5

What does the point where the calibration curve crosses the x-axis signify?

Answer 5

The water potential of the sucrose solution is the same as the potato tissue.

Question 6

Explain why potato cylinders in distilled water increase in length:

Answer 6

Potato has a more negative water potential (hypertonic) to the distilled water so water enters by osmosis causing cells to become turgid.

Question 7

What is a serial dilution?

Answer 7

The step-by-step dilation of a substance in solution.