Cell Membrane Structure and Function

The video explores the structure and function of cell membranes, emphasizing their role in regulating material passage and maintaining cellular boundaries. It discusses the fluid mosaic model, phospholipid behavior, and factors affecting membrane fluidity, such as temperature and cholesterol. The video also covers selective permeability, explaining which molecules can pass through the membrane and the role of cell walls in certain organisms.

What is the primary function of the cell membrane?

• To synthesize proteins

• To store genetic information

• To regulate the passage of materials

• To produce energy for the cell

Which molecule is most abundant in the cell membrane?

• Carbohydrates

• Phospholipids

• Cholesterol

• Proteins

What is the fluid mosaic model?

• A model that describes the static arrangement of proteins in the membrane

• A model illustrating the rigid nature of cell membranes

• A model explaining the flexibility and dynamic nature of cell membranes

• A model describing the solid structure of cell walls

How do unsaturated fatty acids affect membrane fluidity?

• They increase fluidity by preventing tight packing

• They have no effect on fluidity

• They decrease fluidity by packing tightly

• They make the membrane more rigid

What role does cholesterol play in the cell membrane?

• It acts as a protein transporter

• It decreases fluidity at moderate temperatures

• It increases membrane permeability

• It stores energy for the cell

What determines whether a molecule can pass through the cell membrane?

• Its electrical charge and density

• Its temperature and pressure

• Its solubility in water and size

• Its color and shape

Which molecules can pass directly through the cell membrane without assistance?

• Proteins and carbohydrates

• Gases like oxygen and carbon dioxide

• Ions like sodium and calcium

• Large polar molecules

What is the primary function of cell walls in plants, fungi, and bacteria?

• To store genetic information

• To provide physical support

• To regulate the passage of materials

• To synthesize proteins

What is the relationship between membrane fluidity and permeability?

• They are inversely proportional

• They are directly proportional

• They are unrelated

• They are the same

What is the main component of plant cell walls?

• Peptidoglycans

• Cellulose

• Phospholipids

• Chitin