Cell Membrane Transport Mechanisms Explained

The video explains the plasma membrane's role in regulating molecule passage through selective permeability. It covers three transport types: passive (diffusion, osmosis, facilitated diffusion), active (requiring ATP, e.g., sodium-potassium pump), and bulk transport (endocytosis, exocytosis). Each transport type is detailed, highlighting their mechanisms and examples.

What characteristic of the plasma membrane allows it to regulate the passage of molecules?

• It is rigid and inflexible.

• It is electrically charged.

• It is selectively permeable.

• It is completely impermeable.

Which of the following is NOT a form of passive transport?

• Diffusion

• Facilitated diffusion

• Endocytosis

• Osmosis

During diffusion, molecules move from an area of _______ concentration to an area of _______ concentration.

• low; high

• low; low

• high; low

• equal; equal

What role do aquaporins play in the cell?

• They assist in the formation of vesicles.

• They pump sodium ions out of the cell.

• They facilitate the rapid transport of water molecules.

• They transport ions across the membrane.

Active transport requires energy in the form of _______.

• carbon dioxide

• oxygen

• ATP

• glucose

Which of the following is an example of active transport?

• Sodium-potassium pump

• Facilitated diffusion

• Osmosis

• Phagocytosis

What is the process called when the plasma membrane engulfs a large particle?

• Phagocytosis

• Exocytosis

• Pinocytosis

• Facilitated diffusion

Which type of endocytosis involves the formation of vesicles around liquids or very small particles?

• Exocytosis

• Receptor-mediated endocytosis

• Pinocytosis

• Phagocytosis

What happens during exocytosis?

• Ions are pumped against their concentration gradient.

• Membrane-bound vesicles release their contents outside the cell.

• Molecules move down their concentration gradient.

• Vesicles form around particles and bring them into the cell.

Which type of transport involves vesicle formation and metabolic energy?

• Bulk transport

• Facilitated diffusion

• Active transport

• Passive transport