Understanding Plasma Membranes

What is the structure of all plasma membranes?

• Fluid mosaic model without carbohydrates

• Single-layer lipid membrane with no proteins

• Phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates.

• Rigid structure made of cellulose

Name the key components of plasma membranes: _____.

What type of lipid is primarily found in the membrane?

• Sterols

• Phospholipids

• Triglycerides

• Waxes

How do membrane proteins behave within the bilayer?

• Membrane proteins behave as integral or peripheral proteins, with integral proteins spanning the bilayer and peripheral proteins attached to its surfaces.

• Membrane proteins do not interact with the lipid bilayer at all.

• All membrane proteins are identical in structure and function.

• Membrane proteins are only found on the outer surface of the bilayer.

List the three major lipids present in the membrane.

• sphingolipids

• triglycerides

• phospholipids, cholesterol, glycolipids

• fatty acids

What are the two specific areas of a phospholipid?

• Water-loving head and water-repelling tails

• Charged head and neutral tails

• Hydrophilic head and hydrophobic tails

• Polar head and nonpolar tails

Define the term 'hydrophobic' in the context of phospholipids.

• Hydrophobic indicates the ability of phospholipids to dissolve in water.

• Hydrophobic refers to the water-repelling part of phospholipids, specifically the fatty acid tails.

• Hydrophobic describes the polar head of phospholipids.

• Hydrophobic refers to the water-attracting part of phospholipids.

What happens to the phospholipid tails when they contain a double bond?

• The phospholipid tails lose their fluidity and become solid.

• The phospholipid tails become more rigid and tightly packed.

• The phospholipid tails increase in length and density.

• The phospholipid tails become more fluid and less tightly packed.

How does the straightness of phospholipid tails affect membrane properties?

• Straight phospholipid tails have no effect on membrane properties.

• Straight phospholipid tails increase membrane rigidity and decrease fluidity.

• Curved phospholipid tails increase membrane rigidity and decrease fluidity.

• Straight phospholipid tails decrease membrane rigidity and increase fluidity.

What is the role of cholesterol in the plasma membrane?

• Cholesterol maintains membrane fluidity and stability.

• Cholesterol acts as a receptor for signaling molecules.

• Cholesterol serves as a primary energy source for the cell.

• Cholesterol enhances the permeability of the membrane.