The Role and Structure of the Cell Membrane in Biological Systems

The video explains the structure and function of cell membranes, focusing on their semi-permeability. It details the composition of cell membranes, primarily made of phospholipids, and describes their hydrophilic and hydrophobic properties. The formation of the phospholipid bilayer is discussed, along with how different molecules, such as gases, water, and ions, interact with the cell membrane. The video emphasizes the importance of the cell membrane in protecting cells and regulating the passage of substances.

What is the primary function of the cell membrane?

• To protect the cell and regulate what enters and exits

• To synthesize proteins

• To produce energy for the cell

• To store genetic information

Which of the following is NOT a component of a phospholipid?

• Two fatty acid tails

• Nucleic acid chain

• Glycerol backbone

• Phosphate head group

What term describes a molecule with both hydrophilic and hydrophobic parts?

• Isotonic

• Amphipathic

• Hypertonic

• Hydrostatic

How do phospholipids arrange themselves in water to form a bilayer?

• Phosphate heads face inward, tails face outward

• Tails face inward, phosphate heads face outward

• Phosphate heads and tails both face outward

• Tails face each other, phosphate heads face away from each other

Which type of molecules can easily pass through the cell membrane?

• Large polar molecules

• Large nonpolar molecules

• Charged ions

• Small nonpolar molecules

Why can't glucose pass through the cell membrane easily?

• It is too small

• It is a gas

• It is nonpolar

• It is large and polar

What is an example of a small nonpolar molecule that can pass through the cell membrane?

• Sodium ion

• Water

• Oxygen

• Glucose

Which of the following molecules is likely to pass through the cell membrane slowly due to its size and polarity?

• Ethanol

• Benzene

• Chloride ion

• Amino acid

What property of the cell membrane allows it to regulate the passage of substances?

• Semi-permeability

• Permeability

• Impermeability

• Conductivity

What is the main reason the cell membrane prefers nonpolar molecules?

• Because they are charged

• Due to the hydrophobic region of the membrane

• Due to the hydrophilic region of the membrane

• Because they are larger