Diffusion-Osmosis Pre-Lab

Diffusion & Osmosis Pre-Lab

Multiple Choice

In diffusion, which way do substances cross a semi-permeable membrane?

• from low concentration to high concentration

• from high concentration to low concentration

Multiple Select

In osmosis, which way does water cross a semi-permeable membrane? (pick 2)

• from low solute concentration to high solute concentration

• from high solute concentration to low solute concentration

• from high "water concentration" to low "water concentration"

• from low "water concentration" to high "water concentration"

Match

Match the following process with its description:

• passive transport

• active transport

• diffusion

• osmosis

does not require energy

requires energy

passive transport of anything

passive transport of water

• does not require energy

• requires energy

• passive transport of anything

• passive transport of water

​Dialysis Tubing Diagram from bioninja.com.au 

​Size of pore in dialysis tubing vs. Size of particle

Reorder

Drag the substances in size order. 1 = smallest, 4 = largest

• water

  18 Da

• sodium ion

  23 Da

• iodine

  254 Da

• starch

  100 kDa

1

2

3

4

• 1
• 2
• 3
• 4

Multiple Select

How does dialysis tubing help us model diffusion and osmosis? (pick 3)

• pores allow the flow of water, like aquaporin channels

• pores allow small particles through, like passive transport

• pores don't allow large molecules through, like selectively permeable membranes

• pores pull large molecules through, like active transport

Open Ended

Why are these processes important for maintaining homeostasis?

Multiple Choice

What was the tonicity of the starch solution in the sac compared to the water + iodine solution in the beaker?

• sac solution was hypertonic to the beaker solution

• sac solution was hypotonic to the beaker solution

• sac solution was isotonic to the beaker solution

Multiple Choice

How would you describe the results of this demonstration?

• sac was hypertonic so water moved in by osmosis

• sac was hypotonic so starch moved out by diffusion

• sac was hypertonic so water moved out by osmosis

• sac was hypotonic so starch moved in by diffusion

Poll

In our lab, we will use dialysis tubing sacs filled with either distilled water, 1% starch solution, 1% iodine solution, or 10% sodium chloride solution.

MAKE A PREDICTION: Which substances will pass through the dialysis tubing?

• salt

  NaCl

• water

  H₂O

• starch

  C₆H₁₀O₅

• iodine

  I₂