Plasma Membrane Review

Which of the following is the main component of the plasma membrane?

• Cellulose

• Phospholipids

• Glycogen

• Starch

What is the primary function of the plasma membrane?

• Protein synthesis

• Energy production

• Regulating the movement of substances in and out of the cell

• DNA replication

Which model best describes the structure of the plasma membrane?

• Lock and key model

• Fluid mosaic model

• Double helix model

• Sliding filament model

Which of the following best describes the arrangement of phospholipids in the plasma membrane?

• Single layer with hydrophobic tails facing outwards

• Double layer with hydrophobic tails facing inwards

• Double layer with hydrophilic tails facing inwards

• Single layer with hydrophilic heads facing inwards

Which molecule helps to maintain the fluidity of the plasma membrane in animal cells?

• Cholesterol

• Glucose

• DNA

• RNA

Which statement best explains why the plasma membrane is described as "selectively permeable"?

• It allows all substances to pass through freely.

• It allows only certain substances to pass through while blocking others.

• It is impermeable to all substances.

• It allows only water to pass through.

Which of the following best explains how the fluid mosaic model accounts for the movement of proteins within the plasma membrane?

• Proteins are fixed in place and cannot move.

• Proteins can move laterally within the lipid bilayer.

• Proteins are only found on the outside of the membrane.

• Proteins are only found on the inside of the membrane.

Which of the following best describes the role of carrier proteins in the plasma membrane?

• They provide structural support.

• They facilitate the transport of specific molecules across the membrane.

• They store genetic information.

• They produce energy.

Why is the plasma membrane described as a "mosaic" in the fluid mosaic model?

• It is made of a single type of molecule.

• It contains a variety of proteins and lipids arranged in a pattern.

• It is completely rigid.

• It is made only of carbohydrates.

A mutation causes a cell to produce plasma membranes without cholesterol. Predict how this would affect the cell at different temperatures.

• The membrane would become too rigid at low temperatures and too fluid at high temperatures.

• The membrane would remain unchanged.

• The membrane would become more permeable to DNA.

• The membrane would become impermeable to all substances.