AP Bio: Understanding Cell Membranes

What is the most abundant lipid in most cell membranes?

• Cholesterol

• Phospholipids

• Glycolipids

• Triglycerides

Which part of a phospholipid is hydrophilic?

• The fatty acid tails

• The phosphate head

• The entire molecule

• The glycerol backbone

What structure is formed by two layers of phospholipids in a cell membrane?

• Micelle

• Liposome

• Bilayer

• Monolayer

What property of the cell membrane allows only some molecules to pass through?

• Permeability

• Rigidity

• Selective permeability

• Flexibility

According to the fluid-mosaic model, what is the cell membrane composed of?

• A rigid layer of proteins

• A static layer of lipids

• A mosaic of proteins in a fluid bilayer of phospholipids

• A solid layer of carbohydrates

What effect does cholesterol have on membrane fluidity at high temperatures?

• Increases fluidity

• Decreases fluidity

• Has no effect

• Solidifies the membrane

What is the role of glycoproteins in the cell membrane?

• Energy storage

• Cell recognition and communication

• Structural support

• Transport of molecules

What happens to membrane fluidity when phospholipids have unsaturated hydrocarbon tails?

• It becomes more fluid

• It becomes less fluid

• It remains unchanged

• It solidifies

What is the consistency of a properly functioning cell membrane compared to?

• Butter

• Water

• Salad oil

• Honey

What can phospholipids form when they are not part of a cell membrane?

• Proteins

• Micelles and liposomes

• Carbohydrates

• Nucleic acids