Osmosis and diffusion report sheet

Osmosis

Experiment (dry lab)

There are 3 diagrams of animal cells (a, b, c) and 3 diagrams of plant cells (a, b, c) in solutions of varying tonicity. Label the diagrams as isotonic solution, hypertonic solution, or hypotonic solution.

Animal cells:
(a)	Hypotonic
(b)	Isotonic
(c)	Hypertonic
Plant cells:
(a)	Hypotonic
(b)	Isotonic
( c)	Hypertonic

Effect of temperature and size

Observe the agar plate at 25°C, 30 min.

Experiment (dry lab)

Potassium permanganate at{" "} 25°C		Janus Green at 25°C
Time	Distance in mm	Time	Distance in mm
30 min	25	30 min	20

Potassium permanganate (294 Daltons) and Janus Green (511 Daltons) dyes

Which dye has greater diffusion,{" "} potassium permanganate or Janus Green ?	Potassium Permanganate
Why?	The molecular weight of Potassium Permanganate is less so it diffuses quicker.

Observe the agar plate at 5°C, 30 min.

Experiment (dry lab)

Potassium permanganate at{" "} 5°C		Janus Green at 5°C
Time	Distance in mm	Time	Distance in mm
30 min	23	30 min	18

Potassium permanganate (294 Daltons) and Janus Green (511 Daltons) dyes

Which dye has greater diffusion{" "} potassium permanganate or Janus Green?	Potassium Permanganate
Why?	The molecular weight of Potassium Permanganate is less so it diffuses quicker.

Compare the agar plates at 5°C and 25°C.

Experiment (dry lab)

Which agar plate shows greater diffusion,{" "} 5°C or 25°C?	Potassium Permanganate
Why?	The molecular weight of Potassium Permanganate is less so it diffuses quicker.

Effect of temperature on diffusion of iodine

Experiment (at home lab)

QUESTIONS

Temperature of your cups:	169°C	25°C
Is the food coloring evenly distributed in each?	No
Explain.	Higher temperatures tend to increase rate of diffusion (which will distribute evenly)

Effect of solute concentration

Experiment (dry lab)

In the weight change column, record if the bag should increase in weight, decrease in weight, or stay about the same.

#	Bag contents	Beaker contents	Weight change (bag increases, decreases or stays about the same)	Beaker contents (isotonic, hypotonic or hypertonic solution)
1	10 ml Distilled water	200 ml Distilled water	Same	Hypertonic
2	10 ml 10% sucrose	200 ml Distilled water	Increase	Isotonic
3	10 ml 20% sucrose	200 ml Distilled water	Increase	Isotonic
4	10 ml 40% sucrose	200 ml Distilled water	Increase	Isotonic
5	10 ml Distilled water	200 ml 40% sucrose	Decrease	Hypotonic
Which bag should gain the most weight?			4

Differential permeability of membranes

Experiment (dry lab)

Test for	Is test positive or negative?
Starch	Negative
Protein	Negative
Chloride ion	Positive
Sulfate ion	Positive

Which ones (starch, protein, chloride ions, sulfate ions) moved through the dialysis tubing and into the beaker?	Chloride ions and Sulfate Ions
Why did some not move from the bag into the beaker?	They were too big to pass through the membrane.

Diffusion and osmosis in living cells

Experiment (dry lab)

Osmosis with red blood cells

	Describe the blood cells.
0.9% NaCl , Normal blood cells	Round shapes with something that looks like a nucleus in the middle
10% NaCl, Crenated cells	Shriveled almost popcorn looking
1. What solution causes cells to appear this way? Isotonic, hypertonic or hypotonic solution.	2. What solution causes cells to appear this way? Isotonic, hypertonic or hypotonic solution.
Hypertonic	Isotonic

Osmosis with plant cells

	Describe the plant cells.
0% NaCl, Turgid cells	Chloroplasts are pushed out to periphery of cell
20% NaCl, Plasmolyzed cells	Chloroplasts are pushed to center of cell
1. What solution causes cells to appear this way?{" "} Hypertonic or hypotonic solution.	2. What solution causes cells to appear this way? Hypertonic or hypotonic solution.
Hypotonic	Hypertonic

Diffusion in cucumber cells

Experiment (at home lab)

QUESTIONS

1. When comparing the firmness of the cucumber slices, how would you describe each, firm (turgid cells) or soft (plasmolyzed cells)?{" "}
Cup 1	Turgid Cells
Cup 2	Plasmolyzed Cell
Cup 3	Turgid Cell

2. What caused one to be firm and the other to be soft?

Explain.

The salt forced the water out of the cucumber cells causing them to become flaccid.