Exploring Diffusion and Osmosis in the Lab

The video tutorial explains diffusion and osmosis as transport mechanisms in cells. It covers the concept of selective permeability and uses models like sieves and dialysis tubing to demonstrate these processes. An experiment with starch and iodine in dialysis tubing illustrates osmosis and diffusion, showing how molecules move across cell membranes. The tutorial concludes by analyzing the experiment's results and emphasizing the importance of understanding these processes in biology.

What is the main difference between active and passive transport?

• Active transport requires energy, while passive transport does not.

• Active transport involves water, while passive transport involves solutes.

• Active transport moves molecules from low to high concentration, while passive transport moves them from high to low concentration.

• Active transport only occurs in plants, while passive transport occurs in animals.

What is the primary type of passive transport?

• Active transport

• Osmosis

• Diffusion

• Facilitated diffusion

What does a selectively permeable membrane allow?

• All molecules to pass through freely

• No molecules to pass through

• Only water to pass through

• Only certain molecules and ions to pass through

What is used to demonstrate a selectively permeable membrane on a macroscopic level?

• A microscope

• A beaker

• A sieve

• A dialysis tube

What material is dialysis tubing made of?

• Plastic

• Glass

• Cellulose

• Metal

What process allows water to travel through cell membranes?

• Osmosis

• Active transport

• Facilitated diffusion

• Diffusion

What color is produced when starch and iodine react?

• Green

• Red

• Yellow

• Blue-black

Tags

NGSS.MS-PS1-2

What does the presence of a blue-black color inside the dialysis tubing indicate?

• Water diffused into the tubing

• No diffusion occurred

• Iodine diffused into the tubing

• Starch diffused out of the tubing

What should change if water molecules diffuse into or out of the model cell?

• The color of the solution

• The mass of the bag

• The temperature of the solution

• The size of the pores

Tags

NGSS.MS-LS2-1

What is a limitation of the dialysis tubing model?

• It does not demonstrate osmosis

• It is not identical to all properties of a cell membrane

• It cannot be used in a high school classroom

• It only works with water