Plasma Membrane and Cellular Transport

What is the main function of the plasma membrane in the cell?

• Protect the nucleus of the cell.

• Regulate the passage of substances in and out of the cell.

• Produce energy for the cell.

• Store genetic information.

Which component of the plasma membrane is responsible for its fluidity?

• Carbohydrates

• Proteins

• Cholesterol

• Nucleic acids

What is the role of carbohydrates in the plasma membrane?

• Provide energy to the cell.

• Facilitate cell communication.

• Transport oxygen.

• Store lipids.

What are lipids?

• Small molecules composed of amino acids.

• Large molecules composed of glycerol and three fatty acids.

• Large molecules composed of simple sugars.

• Small molecules composed of nucleotides.

How are phospholipids organized in the phospholipid bilayer?

• In a single layer of phospholipids.

• In two layers of phospholipids arranged head to head.

• In two layers of phospholipids arranged tail to tail.

• In three layers of phospholipids arranged randomly.

What function does the phospholipid bilayer have in the plasma membrane?

• It allows the plasma membrane to be rigid and not flexible.

• It allows the plasma membrane to survive and function in its aqueous environment.

• It makes the plasma membrane impermeable to all substances.

• It allows the plasma membrane to dissolve in water.

What is the characteristic of the tails of phospholipids in the phospholipid bilayer?

• They are polar and attract water.

• They are non-polar and repel water.

• They are polar and repel water.

• They are non-polar and attract water.

Which part of the phospholipid is attracted to water?

• The hydrophobic tails.

• The polar heads.

• The polar tails.

• The hydrophobic heads.

Why are the heads of phospholipids near the water inside and outside the cell?

• Because they are non-polar.

• Because they have a negative charge and are polar.

• Because they are hydrophobic.

• Because they repel water.

What is the main function of the phospholipid bilayer in cells?

• Act as a selective barrier.

• Produce energy for the cell.

• Store nutrients.

• Destroy toxins.