Cell Structure and Function

Which of the following statements about cholesterol is correct?

• It increases membrane rigidity only
• It decreases membrane permeability only
• It maintains membrane fluidity at varying temperatures
• It has no effect on membrane structure

The fluid mosaic model includes:

• Fixed positions of all proteins
• Rigid bilayer with no movement
• Lateral movement of lipids and proteins
• Only vertical movement of components

Which of the following best defines peripheral proteins?

• Deeply embedded in the membrane
• Covalently bonded to lipids
• Loosely attached to the membrane surface
• Floating freely in the cytoplasm

Which part of the phospholipid is water-repellent?

• Phosphate group
• Glycerol backbone
• Sugar molecule
• Fatty acid chains

Which of the following is a characteristic of integral proteins?

• They are loosely bound to the surface
• They are always on the outer side
• They are soluble in water
• They are embedded in the membrane