Passive Transport: Simple & Facilitated Diffusion

Which two molecules are most likely to cross a cell's phospholipid bilayer by simple diffusion?

• Sugar molecules

• Water

• Carbon dioxide (CO₂)

• Potassium ions

• Oxygen (O₂)

Which of the following accurately describes dynamic equilibrium?

• Molecules stop moving through the cell membrane

• Molecules move into a cell at the same rate as molecules move out of the cell.

• Molecules move into a cell faster than they move out of a cell.

• Molecules move out of a cell faster than they move into the cell.

Which of the following describes the difference between simple diffusion and facilitated diffusion through a cellular membrane?

• Simple diffusion moves particles from an area of low concentration to high concentration; facilitated diffusion moves particles in the opposite direction.

• Simple diffusion moves particles in the direction of the concentration gradient; facilitated diffusion moves particles against the concentration gradient.

• Simple diffusion moves particles through the phospholipid bilayer; facilitated diffusion moves only water across the phospholipid bilayer.

• Simple diffusion moves particles through the phospholipid bilayer of a cell membrane; facilitated diffusion moves particles through transport proteins.

The diagram above represents diffusion through a cellular membrane. Which of the following best describes the role of the protein channel in moving materials through the cell membrane?

• It allows ions to permanently bond and create new compounds once inside the cell.

• It allows sugars and ions to be removed from the cell against the concentration gradient.

• It allows sugars and ions to cross into the cell with the concentration gradient.

• It allows energy to be used to move large molecules and ions across the cell membrane with the concentration gradient.

How is the plasma membrane best described?

• A phospholipid monolayer with embedded proteins surrounding the cell.

• A complex of small protein subunits surrounding the cell

• a phospholipid bilayer with embedded and surface proteins surrounding the cell

• A carbohydrate chain attached to a lipid layer surrounding the cell.

Look at the image of the cell membrane. What structure in the cell membrane is specialized for this type of transport?

• Carrier protein

• Cholesterol

• Phospholipid

• Receptor protein

When does diffusion occur across a cell membrane?

• When the concentration of particles is different on each side of the membrane.

• When the concentration of particles is equal on both sides of the membrane.

• When there are no particles on either side of the membrane.

• When water moves across the membrane.

Which of the following is the cell organelle most responsible for maintaining cellular homeostasis?

• Golgi apparatus

• Nucleus

• Endoplasmic reticulum

• Cell membrane

Tags

NGSS.HS-LS1-3

Which of the following is a requirement for simple diffusion to take place?

• A transport protein

• A carrier molecule

• A transport carbohydrate

• A concentration gradient

Examine the structure in the diagram. What is shown in the area labeled Y?

• Carrier proteins

• Phospholipid bilayer

• Phosphorous bilayer

• Receptor proteins