Friday, October 17, 2025

Lab: Osmosis & 2.7 Tonicity and Osmoregulation continued

 

Today's Learning Objective(s):

Explain how osmoregulatory mechanisms contribute to the health and survival of organisms.

Tasks:

 

 

1

More sample water potential problems

 

Let’s try a few water potential (Ψ) problems:

 

a)   An AP biology student is experimenting with water potential using artificial plant cells. She would like to cause an increase in the solute potential (Ψs) of the solution. Which factor would cause that to happen?

a.    Increasing temperature

b.    Lowering the ionization constant

c.    Increasing solute concentration

d.    nothing will change the concentration

 

b)   What is the water potential (Ψ) of a sucrose solution at 25°C with a solute concentration of 0.2 M, and open to the atmosphere? If this was placed in a container with root tissue with a water potential (Ψ) of -0.49 bars, how would the water flow?

 

c)    If a plant cell has a water potential of -0.6 bars and is placed in a solution of 0.1M NaCl at 20°C, how would the water flow?

 

Formula Sheet

 

2

Lab: Osmosis (part 2) day 2

 Think About It... Why are we only using plant cells for the water potential problems and labs?

Using the solutions in the lab (0.0M → 1.0M and X Mystery), place pre-massed cubes of carrots into cups. You will use the solutions to determine the water potential of the carrot cells. 

 

3

More Water Potential Problems - Worksheet

 

Use the worksheet to try some water potential problems.

 

Worksheet

Formula Sheet

4

Quiz: Plasma Membrane Corrections

 

Let’s pass back the quizzes with 20 minutes of the class remaining. Review your answers. Make corrections.
MCQs 0.5 pts for each corrected answer
FRQs ½ credit for each item on the scoring response guide

 

Homework

2.7.Watch Daily Video 3

Tuesday, 10/21/25 Quiz: Cell Transport 

 

Upcoming Assessments

Tuesday, 10/21/25 Quiz: Cell Transport 

Friday, 10/24/25 Test: Cells (unit 2)

 

Calendar Notes

Thursday, 10/30/25 Q1 Grading Period Ends