Cell membrane

 Q: What is the cell membrane?

A: The cell membrane, also known as the plasma membrane, is a thin, semi-permeable barrier that surrounds the cell, separating its internal environment from the external surroundings.

Q: What is the composition of the cell membrane?

A: The cell membrane is primarily composed of phospholipids, proteins, cholesterol, and carbohydrates.

Q: What is the main function of the cell membrane?

A: The cell membrane regulates the passage of substances in and out of the cell, maintaining the cell's internal environment and selectively allowing certain molecules to cross.

Q: How does the structure of the cell membrane contribute to its function?

A: The phospholipid bilayer provides a flexible structure, allowing the membrane to be selectively permeable, while proteins embedded in the membrane perform various functions such as transport, signaling, and cell recognition.

Q: What is meant by the term "selectively permeable" in relation to the cell membrane?

A: Selectively permeable means that the cell membrane allows certain substances to pass through while restricting the passage of others, ensuring a controlled environment within the cell.

Q: How do integral and peripheral proteins differ in their association with the cell membrane?

A: Integral proteins are embedded within the lipid bilayer, while peripheral proteins are loosely bound to the membrane's surface.

Q: What role does cholesterol play in the cell membrane?

A: Cholesterol helps maintain the fluidity and stability of the cell membrane by preventing the fatty acid chains of phospholipids from packing too closely.

Q: How do cells communicate through the cell membrane?

A: Cells communicate through the cell membrane using proteins that act as receptors, allowing them to detect and respond to external signals, such as hormones or other cells.

Q: Can you explain the process of passive transport across the cell membrane?

A: Passive transport involves the movement of substances across the cell membrane without the input of energy, driven by concentration gradients. Diffusion and facilitated diffusion are examples of passive transport.