Cell Membrane Structure and Function in Living Organisms

Professor Dave explains the cell membrane's structure and function, highlighting its semipermeable nature and the phospholipid bilayer. He discusses the roles of cholesterol and proteins, including channel and carrier proteins, in facilitating transport across the membrane. The video covers passive and active transport mechanisms, emphasizing diffusion and the use of ATP in active transport. Various proteins, such as glycoproteins and receptor proteins, are also discussed for their roles in cell recognition and signal reception.

What is the primary function of the cell membrane?

• To produce energy for the cell

• To separate the cell's interior from the external environment

• To store genetic information

• To synthesize proteins

What is the structure of the cell membrane primarily composed of?

• A layer of carbohydrates

• A layer of proteins

• A phospholipid bilayer

• A single layer of phospholipids

Why is the cell membrane described as a 'fluid mosaic'?

• Because it is made of a single type of molecule

• Because the phospholipids and proteins are fixed in place

• Because the phospholipids and proteins can move around

• Because it is solid and rigid

What role does cholesterol play in the cell membrane?

• It makes the membrane more fluid

• It gives the membrane rigidity

• It helps in protein synthesis

• It provides energy for the cell

How do small nonpolar molecules like oxygen cross the cell membrane?

• Through endocytosis

• By simple diffusion

• By facilitated diffusion

• Through active transport

What is facilitated diffusion?

• Movement of molecules with the concentration gradient without energy

• Movement of molecules against the concentration gradient

• Movement of molecules through vesicles

• Movement of molecules with the concentration gradient using energy

Which type of transport requires energy expenditure?

• Simple diffusion

• Passive transport

• Facilitated diffusion

• Active transport

What is the role of a sodium-potassium pump?

• To transport water molecules

• To facilitate the diffusion of glucose

• To move sodium ions out of the cell and potassium ions in

• To move sodium ions into the cell and potassium ions out

What is the function of aquaporins in the cell membrane?

• To provide structural support

• To move ions across the membrane

• To transport glucose

• To facilitate the movement of water

What is the role of receptor proteins in the cell membrane?

• To synthesize proteins

• To provide energy

• To receive signals from outside the cell

• To transport ions