What is the difference between passive and active transport across the cell membrane?

Answer 1

Wouldn't it be that active transport requires enegry and passive doesn't? Passive transport occurs when the concentration of something on one side of membrane is different from the concentration on the other side. It occurs when that substance can pass through the membrane, and always in the direction of more -> less. No energy is required to make the substance move; in fact, this movement generates energy. This is like rolling a rock down a hill--it just does it on its own.

Active transport occurs in the opposite direction, from less -> more. It requires energy for transport. This is like rolling a rock up a hill--you have to push it the entire way!

Both involve the transport of a substance across a membrane, and the change in concentrations on different sides of a membrane. Both are also important to the proper functioning of a cell.

Active transport requires energy, but passive transport requires none.

Active transport requires a special protein to make the transport occur, but passive transport requires none.

Answer 2

Active transport requires the expenditure of energy for molecules to move across the cll membrane. Examples include:

• Use of ATP molecules for the movement of ions or molecules across the cell membrane
  
• Movement of ions with the help of a protein gate

Passive transport does not require ATP molecules for molecules to move across the cell membrane. An ideal example is diffusion of organic molecules from outside the cell into the cytoplasm.

Answer 3

Passive when molecules passing through the cell membrane without using any energy. Active when cell uses energy to take some molecules in.