1.3 Membrane Proteins

What type of interaction holds integral membrane proteins within the phospholipid bilayer?

• Ionic interactions

• Hydrogen bonds

• Hydrophobic interactions

• Covalent bonds

Which type of membrane protein interacts with the hydrophobic region of membrane phospholipids?

• Peripheral membrane proteins

• Glycoproteins

• Integral membrane proteins

• Enzymatic proteins

How do peripheral membrane proteins primarily bind to the surface of membranes?

• Covalent bonds

• Ionic and hydrogen bond interactions

• Hydrophobic interactions

• Disulfide bridges

Which of the following molecules can pass through the phospholipid bilayer by simple diffusion?

• Glucose

• Sodium ions

• Oxygen

• Proteins

What is the primary characteristic of channel proteins in cell membranes?

• They are always open for passive transport.

• They form water-filled pores that extend across the membrane.

• They bind to specific substances and change shape.

• They hydrolyse ATP to transport ions.

Which of the following is true about ligand-gated channels?

• They are controlled by changes in ion concentration.

• They are always open.

• They are controlled by the binding of signal molecules.

• They transport substances using ATP.

What energy source is required for the active transport of ions across a membrane?

• Concentration gradient

• Facilitated diffusion

• ATP hydrolysis

• Simple diffusion

What does the sodium-potassium pump use to drive the transport of sodium and potassium ions?

• Facilitated diffusion

• Electrical potential difference

• Energy from ATP hydrolysis

• Osmosis

How many sodium ions are transported out of the cell for each ATP hydrolysed by the sodium-potassium pump?

• One

• Two

• Three

• Four

What role does the sodium gradient play in the small intestine regarding glucose transport?

• It facilitates glucose diffusion.

• It drives the active transport of glucose.

• It allows glucose to move out of the cell.

• It directly hydrolyses ATP for glucose transport.