Final answer:
The steps of cellular respiration, which convert glucose into ATP, are 1) glycolysis, 2) Acetyl-CoA formation, 3) Krebs cycle, and 4) electron transport chain. Fermentation occurs when oxygen is absent and would serve as a subsequent step to glycolysis.
Step-by-step explanation:
The correct order of steps in cellular respiration is: 1) glycolysis, 2) Acetyl-CoA formation (pyruvate oxidation), 3) Krebs cycle (Citric Acid Cycle), and 4) electron transport chain. Fermentation is an alternative pathway to cellular respiration that occurs when oxygen is not present and would follow glycolysis as step 5.
Cellular respiration is a process by which cells convert nutrients into energy and consists of several essential steps. Cellular respiration begins with glycolysis, where a glucose molecule is split into two molecules of pyruvate in the cytoplasm, either with or without oxygen. Following glycolysis, pyruvate undergoes oxidation to form Acetyl-CoA, which is crucial for the next step. The Krebs cycle, which occurs in the mitochondrial matrix, processes the Acetyl-CoA to produce energy carriers, and CO2 as waste. The electron transport chain, the final stage of cellular respiration, occurs on the inner mitochondrial membrane and involves a chain of redox reactions that lead to the synthesis of a large amount of ATP, the energy currency of the cell. In the absence of oxygen, cells can undergo fermentation after glycolysis, which regenerates the electron carriers used in glycolysis, but yields no ATP from the fermentation process itself. Overall, these steps efficiently convert the energy stored in glucose into ATP, which is vital for cellular functions.