Cell Membrane Transport Concepts

The video tutorial covers diffusion through a membrane, explaining passive transport and dynamic equilibrium. It discusses how molecule size affects diffusion, with large molecules unable to pass through membranes. A lab experiment demonstrates diffusion using starch, iodine, and glucose, highlighting color changes as indicators. Benedict's solution is used to test for glucose presence, showing a color change upon heating. The tutorial concludes with osmosis in red onion cells, illustrating how salt water affects cell structure.

What is the primary characteristic of passive transport?

• Molecules move from low to high concentration.

• Molecules move from high to low concentration without energy.

• It requires energy in the form of ATP.

• It involves the use of transport proteins.

What is dynamic equilibrium in the context of diffusion?

• Particles stop moving completely.

• Particles move equally in both directions across a membrane.

• Particles require energy to move.

• Particles move only in one direction.

Why can't large molecules like starch diffuse across a cell membrane?

• They dissolve in the cell membrane.

• They require energy to move across.

• They are too large to fit through the tiny pores.

• They are repelled by the cell membrane.

Which of the following molecules can diffuse across a cell membrane?

• Starch

• Proteins

• Fats

• Glucose

What color change indicates the presence of iodine inside the artificial cell?

• Amber to blue-black

• Clear to milky white

• Blue to orange

• Red to green

What happens when iodine and starch mix?

• The solution turns blue-black.

• The solution turns red.

• The solution remains clear.

• The solution turns orange.

What is the initial color of Benedict's solution before heating?

• Orange

• Blue

• Green

• Red

What does a color change to orange indicate in the Benedict's test?

• Presence of glucose

• Presence of starch

• Presence of iodine

• Presence of proteins

What is osmosis?

• Diffusion of proteins

• Diffusion of glucose

• Diffusion of water

• Diffusion of iodine

What effect does salt water have on red onion cells?

• It causes the cells to swell.

• It causes the cells to shrink.

• It has no effect on the cells.

• It causes the cells to burst.