Cell Membrane and Nucleus Quiz

What component of the cell membrane is primarily responsible for its selective permeability?

• Cholesterol

• Phospholipid bilayer

• Cytoskeleton

• Ribosomes

Which of the following molecules can pass through the cell membrane via simple diffusion?

• Sodium ions (Na⁺)

• Glucose

• Oxygen (O₂)

• Proteins

What is the main function of the sodium-potassium pump (Na⁺/K⁺ ATPase)?

• To pump sodium into the cell and potassium out

• To pump 3 sodium ions out and 2 potassium ions into the cell

• To transport glucose across the membrane

• To equalize the concentration of Na⁺ and K⁺ inside and outside the cell

Which type of membrane protein forms a pore to allow ions or molecules to pass through the membrane?

• Carrier proteins

• Channel proteins

• Receptor proteins

• Adhesion proteins

Which of the following is a form of active transport?

• Simple diffusion of oxygen

• Facilitated diffusion of glucose

• Movement of ions via the sodium-potassium pump

• Movement of water through aquaporins

How does facilitated diffusion differ from active transport?

• Facilitated diffusion requires ATP, while active transport does not.

• Facilitated diffusion moves molecules against their concentration gradient.

• Facilitated diffusion does not require energy, while active transport does.

• Facilitated diffusion moves water, while active transport moves ions.

What is the role of aquaporins in the cell membrane?

• To actively transport ions

• To allow water molecules to pass through the membrane

• To pump glucose into the cell

• To bind to receptor molecules

Endocytosis is a process by which cells:

• Release substances outside the cell

• Pump ions against their concentration gradient

• Engulf materials from outside the cell by forming vesicles

• Generate ATP for cellular processes

Which of the following is true about passive transport?

• It requires energy in the form of ATP.

• It moves substances against their concentration gradient.

• It occurs via simple diffusion, facilitated diffusion, or osmosis.

• It always requires the use of membrane proteins.

In receptor-mediated endocytosis, what is the primary role of membrane receptors?

• To expel waste materials from the cell

• To bind specific molecules and trigger vesicle formation

• To open ion channels for passive diffusion

• To transport water across the membrane