uses chemical energy for the process of
producing ATP (adenosine triphosphate). ATP is the primary source of energy for cellular processes in living organisms.
producing ATP (adenosine triphosphate), which is the main energy currency in cells. This process is known as cellular respiration.
Step 1: Glycolysis - This process takes place in the cytoplasm and breaks down glucose, a sugar molecule, into two molecules of pyruvate. It also produces a small amount of ATP.
Step 2: Pyruvate Processing - In the presence of oxygen, each pyruvate molecule moves into the mitochondria where it undergoes further processing. Each pyruvate is converted into a molecule called acetyl CoA.
Step 3: Citric Acid Cycle - Acetyl CoA is combined with a molecule called oxaloacetate to form citric acid in the mitochondria. This starts a series of reactions known as the citric acid cycle or Krebs cycle. In this cycle, carbon atoms are gradually released from the acetyl CoA molecule, producing energy-rich molecules such as NADH and FADH2, as well as a small amount of ATP.
Step 4: Electron Transport Chain - The NADH and FADH2 molecules generated in the previous steps carry high-energy electrons to the inner mitochondrial membrane. These electrons are transferred to protein complexes in the electron transport chain, releasing energy along the way. This energy is used to pump protons (H+) across the membrane, creating a proton gradient.
Step 5: ATP Synthesis - The proton gradient generated during the electron transport chain drives the enzyme ATP synthase, which synthesizes ATP. As protons flow through ATP synthase, ADP (adenosine diphosphate) molecules are phosphorylated, producing ATP.
Overall, the process of cellular respiration uses the chemical energy stored in glucose (or other fuel molecules) to produce ATP through glycolysis, pyruvate processing, the citric acid cycle, and the electron transport chain.