Cell Membranes Quiz

The compounds in biological membranes that form a barrier to the movement of hydrophilic materials across the membrane are 

• integral membrane proteins
• carbohydrates
• lipids
• peripheral membrane proteins

In biological membranes, the phospholipids are arranged in a _______, with the_______.

• bilayer; fatty acids pointing toward each other
• bilayer; fatty acids facing outward
• single layer; fatty acids facing the interior of the cell
• single layer; phosphorus-containing region facing the interior of the cell

Which statement about cholesterol molecules is true?

• They help hold a membrane together.
• They alter the fluidity of the membrane.
• They attach to carbohydrates.
• They disrupt membrane function.

Which type of membrane protein would likely be most easily removed in a laboratory experiment?

• Integral membrane proteins
• Channel proteins
• Peripheral membrane proteins
• Transmembrane proteins

A protein that forms an ion channel through a membrane is most likely

• a peripheral membrane protein

• a phospholipid

• an enzyme.

• a integral (transmembrane) protein

The LDL receptor is an integral membrane protein that crosses the plasma membrane, with portions of the protein extending both outside and into the interior of the cell. The amino acid side chains (R groups) in the region of the protein that crosses the membrane are most likely

• charged
• hydrophilic
• hydrophobic
• carbohydrates

The hydrophilic regions of a membrane protein are most likely

• present only in muscle cells
• associated with the fatty acid region of the lipids
• either on the surface or inserted into the interior of the membrane
• exposed on the surface of the membrane

When a mouse cell and a human cell are fused, the membrane proteins of the two cells become uniformly distributed over the surface of the hybrid cell. This occurs because

• many proteins can move around within the bilayer.
• all proteins are anchored within the membrane.
• all proteins in the plasma membrane are peripheral.
• different membranes contain different proteins.

Which of the following functions as a recognition site for interactions between cells?

• Glycolipids

• Fatty acids

• Cholesterol

• Phospholipids

The compounds in biological membranes that form a barrier to the movement of hydrophillic materials across the membrane are

• lipids

• carbohydrates

• integral membrane proteins

• cholesterol