Understanding Diffusion: Simple vs. Facilitated

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

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

• Facilitated diffusion requires transport proteins, while simple diffusion does not.

• Simple diffusion can only move particles out of the cell, while facilitated diffusion can move them in or out.

• Facilitated diffusion can only move water molecules, while simple diffusion can move any type of molecule.

Which type of diffusion is directly through the phospholipid bilayer of a cell membrane?

• Facilitated diffusion

• Simple diffusion

• Active transport

• Osmosis

What types of molecules typically move through the cell membrane via simple diffusion?

• Large polar molecules

• Ions

• Small nonpolar molecules

• Proteins

Why do some molecules require facilitated diffusion to cross the cell membrane?

• They are too large to fit through the phospholipid bilayer.

• They are not soluble in lipids.

• They need to move against their concentration gradient.

• Both A and B are correct.

Which of the following is NOT a characteristic of facilitated diffusion?

• It moves substances down their concentration gradient.

• It requires ATP to function.

• It involves specific transport proteins.

• It can transport ions and polar molecules.

What role do transport proteins play in facilitated diffusion?

• They provide energy for active transport.

• They serve as channels or carriers for specific molecules.

• They break down molecules so they can pass through the membrane.

• They pump molecules against their concentration gradient.

In which scenario would facilitated diffusion be necessary?

• Moving oxygen molecules into a cell

• Exporting small nonpolar waste molecules

• Importing glucose into a cell

• Releasing carbon dioxide from a cell

How does the concentration gradient affect facilitated diffusion?

• It does not affect facilitated diffusion.

• Movement occurs from an area of low concentration to an area of high concentration.

• Movement occurs from an area of high concentration to an area of low concentration.

• The concentration gradient reverses the direction of facilitated diffusion.

Which statement is true about both simple and facilitated diffusion?

• Both require ATP to move molecules across the cell membrane.

• Both can move molecules against their concentration gradient.

• Both involve the movement of molecules from higher to lower concentration.

• Both use transport proteins to move molecules across the cell membrane.

What determines the specificity of a transport protein in facilitated diffusion?

• The size of the protein

• The shape and charge of the molecule it transports

• The concentration gradient across the membrane

• The amount of ATP available