Exploring Diffusion Through A Membrane Lab

This video tutorial guides students through the New York State Living Environment Lab on diffusion through a membrane. It covers the preparation of dialysis tubing with glucose and starch solutions, chemical testing using indicators, and setting up a wet mount slide for microscope viewing. The tutorial emphasizes safety and accuracy in conducting experiments, providing step-by-step instructions for each part of the lab.

What is the purpose of using iodine solution in the experiment?

• To indicate the presence of starch

• To indicate the presence of glucose

• To dissolve the starch solution

• To clean the dialysis tubing

Why is it important to twist and tie the dialysis tubing tightly?

• To allow better diffusion

• To ensure the solutions do not leak out

• To make it easier to handle

• To prevent air from entering

What should you do after filling the dialysis tubing with glucose and starch solutions?

• Place it directly in the beaker

• Tie off the top of the tube

• Heat the tubing

• Add iodine solution inside the tubing

What color should the water in the beaker turn after adding the starch indicator solution?

• Red

• Amber

• Blue

• Green

What is the purpose of using Benedict's solution in the chemical testing?

• To test for the presence of starch

• To test for the presence of glucose

• To clean the test tubes

• To neutralize the solutions

What indicates a positive test result for starch when using iodine?

• A yellowish color

• A black-blue color

• A red color

• No color change

What safety precaution should be taken when placing test tubes in the hot water bath?

• Overfill the water bath

• Ensure the test tube openings are away from people

• Point the test tube openings towards people

• Use bare hands to handle the test tubes

What is the first step in preparing a wet mount slide?

• Place the red onion skin on the slide

• Add two to three drops of freshwater to the slide

• Add saltwater to the slide

• Cover the slide with a coverslip

Why do you lower the coverslip gently onto the microscope slide?

• To dry the specimen

• To make the slide look neat

• To reduce the amount of air bubbles

• To prevent the specimen from moving

What is the purpose of adding salt solution to the wet mount slide?

• To stain the onion cells

• To observe osmosis in the onion cells

• To dissolve the onion skin

• To clean the slide