Cells get energy through a process called respiration. This mainly happens by turning glucose into a substance called adenosine triphosphate, or ATP for short. ATP is important because it gives cells the energy they need to work.

There are two main types of respiration:

1. Aerobic Respiration:

   • This happens when there is oxygen around.
   • It can produce up to 38 ATP molecules from one glucose molecule.
   • It has three important steps:
     • Glycolysis: This step breaks glucose down into smaller parts called pyruvate and produces 2 ATP.
     • Krebs Cycle: In this step, pyruvate is processed to make high-energy carriers called NADH and FADH2. This step also produces 2 ATP.
     • Electron Transport Chain: This is the final step where up to 34 ATP can be made.

2. Anaerobic Respiration:

   • This occurs when there is no oxygen.
   • It only makes 2 ATP from one glucose molecule.
   • It includes processes like fermentation.

In short, cellular respiration is really important. It helps cells change food energy into a form they can use, which is essential for life.