STC BIOL 1406 CH.5 Practice Question Quiz

Which model describes the plasma membrane as a dynamic mixture of lipids, proteins, and carbohydrates?

• Sandwich model

• Fluid mosaic model

• Layered protein model

• Unit membrane model

Which component provides a flexible barrier to permeability in the fluid mosaic model?

• Proteins

• Carbohydrates

• Phospholipids

• Nucleic acids

What is the main role of carbohydrates in the plasma membrane?

• Provide fluidity

• Serve as energy reserves

• Function as external ID tags for communication and adhesion

• Catalyze reactions

Cholesterol helps maintain membrane fluidity by:

• Acting as a receptor

• Preventing tight packing at low temps and restraining movement at high temps

• Forming pores in the membrane

• Storing energy

Which factor decreases membrane fluidity?

• Unsaturated fatty acids

• High temperature

• Saturated fatty acids

• Cholesterol at low temperature

Which of the following is NOT a plasma membrane function?

• Receiving signals

• Defining borders

• DNA replication

• Cell adhesion

Which transport requires no energy and moves substances down their concentration gradient?

• Passive transport

• Active transport

• Exocytosis

• Endocytosis

Diffusion through the lipid bilayer is limited to:

• Small, nonpolar molecules like O₂ and CO₂

• Glucose

• Ions

• Large proteins

Which of the following will speed up diffusion?

• Greater distance traveled

• Higher solvent density

• Larger molecular mass

• Increased temperature

Facilitated diffusion requires:

• Energy from ATP

• Integral membrane proteins

• Vesicles

• Cholesterol