Answer: The use of energy to move particles against the concentration gradient is called active transport. In active transport, cells use energy, usually in the form of ATP, to move molecules or ions across a cell membrane from an area of lower concentration to an area of higher concentration.
On the other hand, the movement of particles by diffusion without energy is called passive transport. Passive transport includes two main processes: simple diffusion and facilitated diffusion. In simple diffusion, particles move from an area of higher concentration to an area of lower concentration without the need for energy. This process occurs naturally and is driven by the random movement of particles.
Facilitated diffusion, as the name suggests, requires the help of specific carrier proteins to transport molecules across the cell membrane. These carrier proteins assist in the movement of molecules down their concentration gradient, without the input of energy.
Lastly, the movement of particles along the concentration gradient refers to passive transport. It occurs when particles move from an area of higher concentration to an area of lower concentration, without the use of energy. This process helps to equalize the concentration of particles on both sides of the membrane.
To summarize:
- Active transport requires energy to move particles against the concentration gradient.
- Passive transport includes simple diffusion and facilitated diffusion, where particles move without energy.
- Movement of particles along the concentration gradient is a type of passive transport.
I hope this helps!