Final answer:
Glycolysis is the breakdown of glucose, and fermentation can occur if oxygen is limited. Anabolism builds complex molecules, while catabolism breaks them down. ATP stores energy, and when converted to ADP, releases energy for cellular processes. Electron transport generates a proton gradient used in oxidative phosphorylation to produce ATP.
Step-by-step explanation:
Glycolysis and Fermentation
Glycolysis is the initial step in cellular respiration, where glucose is broken down into two molecules of pyruvate. This process occurs in the cytoplasm of the cell and does not require oxygen. If oxygen is lacking, pyruvate can undergo fermentation, a process that regenerates the electron carrier NAD+ by converting pyruvate to either lactic acid or ethanol.
Anabolism and Catabolism
Anabolism refers to the metabolic pathways that build complex molecules from simpler ones. It requires energy input and is involved in processes like protein synthesis and DNA replication. On the other hand, catabolism is the breakdown of complex molecules into simpler ones, releasing energy. Both anabolism and catabolism are interconnected and contribute to the overall metabolism of an organism.
ATP and ADP
ATP (adenosine triphosphate) and ADP (adenosine diphosphate) are molecules involved in energy transfer within cells. ATP stores energy in its high-energy phosphate bonds, and when one phosphate group is removed, it becomes ADP, releasing energy that can be used by the cell. This cycle of ATP to ADP and vice versa is crucial for providing energy for various cellular processes.
Electron Transport and Oxidative Phosphorylation
Electron transport is a series of reactions that occur in the inner mitochondrial membrane. During this process, electrons from NADH and FADH2, generated in previous metabolic pathways like glycolysis and the citric acid cycle, are passed along a chain of protein complexes, pumping protons across the membrane. The final protein complex, cytochrome c oxidase, transfers the electrons to oxygen, forming water. This electron flow generates a proton gradient, which drives ATP synthesis through oxidative phosphorylation. The enzyme ATP synthase uses the energy from the proton gradient to convert ADP to ATP.