Diffusion Mechanisms and Characteristics

The video explains diffusion as the movement of substances along an electrochemical gradient. It covers two types: simple diffusion, where molecules pass directly through the membrane, and facilitated diffusion, which involves carrier proteins. Simple diffusion is faster as it doesn't involve chemical interactions, while facilitated diffusion is slower due to carrier protein interactions. Factors affecting diffusion rates include concentration, electrical, and pressure gradients. The video concludes with a summary of these concepts.

What is the primary difference between simple diffusion and facilitated diffusion?

• Simple diffusion occurs directly through the membrane, while facilitated diffusion involves carrier proteins.

• Simple diffusion involves chemical interaction with the passage, while facilitated diffusion does not.

• Simple diffusion is slower than facilitated diffusion.

• Simple diffusion requires energy, while facilitated diffusion does not.

Which of the following substances can diffuse directly through the lipid bilayer?

• Water

• Sodium ions

• Glucose

• Oxygen

What factor does NOT affect the rate of simple diffusion?

• Number of carrier proteins

• Size of the molecule

• Velocity of kinetic motion of molecules

• Lipid solubility of the substance

In facilitated diffusion, what limits the speed of diffusion?

• The concentration gradient

• The number of available channels

• The size of the molecules

• The speed of conformational changes in carrier proteins

What is Vmax in the context of facilitated diffusion?

• The maximum speed of diffusion when all carrier proteins are occupied

• The maximum concentration gradient

• The maximum size of molecules that can be transported

• The maximum number of molecules that can pass through a channel simultaneously

Which gradient does NOT affect the rate of diffusion?

• Pressure gradient

• Electrical gradient

• Concentration gradient

• Temperature gradient

How does a higher concentration gradient affect diffusion?

• It speeds up the diffusion process.

• It has no effect on diffusion.

• It reverses the direction of diffusion.

• It slows down the diffusion process.

What role does electronegativity inside the cell play in diffusion?

• It has no effect on diffusion.

• It reverses the direction of diffusion.

• It speeds up the diffusion of positively charged ions.

• It slows down the diffusion of positively charged ions.

Which of the following is true about simple diffusion?

• Multiple molecules can pass simultaneously.

• It involves chemical interaction with the passage.

• It requires carrier proteins.

• It is a saturable process.

What is a characteristic of facilitated diffusion?

• It is faster than simple diffusion.

• It does not involve carrier proteins.

• It involves chemical interaction with carrier proteins.

• It is a non-saturable process.