Cell Membrane Structure and Function

The video tutorial covers the cell membrane's structure and function, focusing on its composition of lipids and proteins. It explains how lipid-soluble and water-soluble substances move through the membrane, highlighting the roles of proteins and cholesterol. The concept of selective permeability is discussed in relation to maintaining homeostasis. Feedback mechanisms, both negative and positive, are explained as essential processes for regulating internal conditions.

What are the two main components of the cell membrane?

• Carbohydrates and lipids

• Lipids and proteins

• Proteins and nucleic acids

• Carbohydrates and nucleic acids

Which substances can easily pass through the cell membrane?

• Ions

• Lipid-soluble substances

• Glucose

• Water-soluble substances

What is the role of hydrophilic heads in the cell membrane?

• They repel water

• They attract water

• They stabilize the membrane

• They transport ions

Which type of protein helps water-soluble substances pass through the cell membrane?

• Structural proteins

• Receptor proteins

• Carrier proteins

• Pore proteins

What is the function of cholesterol in the cell membrane?

• It makes the membrane rigid

• It stabilizes the membrane

• It transports glucose

• It acts as a receptor

Why are cell membranes described as selectively permeable?

• They allow only water to pass

• They allow only certain substances to pass

• They block all substances

• They allow all substances to pass

What is homeostasis?

• The process of cell division

• The synthesis of proteins

• The maintenance of equilibrium within cells

• The breakdown of glucose

How does negative feedback help maintain homeostasis?

• By increasing the output

• By promoting cell growth

• By stabilizing conditions

• By disrupting equilibrium

What is an example of positive feedback in the body?

• Blood clotting

• Regulating body temperature

• Balancing electrolytes

• Maintaining blood sugar levels

Which feedback mechanism is similar to a thermostat in a house?

• Positive feedback

• Feedback inhibition

• Neutral feedback

• Negative feedback