Cell Structure and Function

Carbohydrates in the plasma membrane are usually attached to:

• Nucleic acids
• Water molecules
• Cholesterol
• Proteins or lipids

The main function of the cell membrane is:

• Energy production
• Genetic storage
• Selective permeability and boundary maintenance
• Waste excretion

In the phospholipid bilayer, the hydrophobic tails face:

• Toward the extracellular space
• Toward the cytoplasm
• Toward the surface
• Toward the interior of the membrane

The amphipathic nature of phospholipids means they have:

• Two hydrophilic ends
• Two hydrophobic ends
• A hydrophilic head and hydrophobic tail
• Only hydrophobic regions

Cholesterol in the cell membrane primarily affects:

• Membrane thickness
• Membrane rigidity
• Membrane porosity
• Membrane fluidity