Exploring Diffusion and Osmosis in Cell Biology

Dana Murchison, a scientist at Science North, demonstrates three experiments to explain diffusion and osmosis in cell biology. The first experiment uses food coloring to show how temperature affects diffusion. The second experiment uses dialysis tubing to illustrate diffusion across a semi-permeable membrane, highlighting molecule size as a factor. The final experiment demonstrates osmosis using a thistle funnel tube, showing water movement from low to high solute concentration. These experiments provide a practical understanding of molecular movement in cells.

What is the primary focus of the video presented by Dana Murchison?

• Diffusion and osmosis in cell biology

• The lifecycle of a butterfly

• The structure of DNA

• The process of photosynthesis

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What is diffusion?

• Movement of water molecules from high to low concentration

• Movement of molecules from low to high concentration

• Movement of molecules from high to low concentration

• Movement of water molecules from low to high concentration

Why does red food coloring spread faster in hot water compared to blue food coloring in cold water?

• Because blue food coloring is heavier

• Because molecules move faster at higher temperatures

• Because hot water has more molecules

• Because red food coloring is lighter

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What is a semi-permeable membrane?

• A membrane that allows all molecules to pass through

• A membrane that blocks all molecules

• A membrane that allows some molecules to pass through while blocking others

• A membrane that only allows water molecules to pass through

In the first diffusion experiment with dialysis tubing, what indicates that diffusion has taken place?

• A change in the pH of the solutions

• A color change in the tube or beaker

• A temperature change in the beaker

• A change in the volume of the solutions

What was the result of the first diffusion experiment with potassium thiocyanate and iron III chloride?

• No color change in either the tube or the beaker

• Color change in both the tube and the beaker

• Color change only in the tube

• Color change only in the beaker

In the second diffusion experiment, why did the iodine solution cause a color change in the beaker but not in the tube?

• Because the starch molecules were too large to pass through the membrane

• Because the iodine molecules were too large to pass through the membrane

• Because the iodine solution was not mixed properly

• Because the starch solution was too concentrated

What is osmosis?

• Movement of solute molecules from low to high concentration

• Movement of water molecules from high to low solute concentration

• Movement of water molecules from low to high solute concentration

• Movement of solute molecules from high to low concentration

In the osmosis experiment, what is the expected result when the thistle funnel tube is suspended in distilled water?

• The level of fluid in the tube will remain the same

• The level of fluid in the tube will rise

• The level of fluid in the beaker will rise

• The level of fluid in the tube will decrease

What is the role of the semi-permeable membrane in the osmosis experiment?

• To allow solute molecules to pass through while blocking water molecules

• To allow water molecules to pass through while blocking solute molecules

• To allow all molecules to pass through

• To block all molecules