Metabolic Pathways
Think of metabolic pathways as assembly lines in a factory - they're series of chemical reactions that start with raw materials (substrates) and end with finished products. Your body runs thousands of these pathways simultaneously, including respiration, protein synthesis, and photosynthesis in plants.
Each step in a pathway needs a specific enzyme to make it happen. The product from one reaction becomes the starting material for the next, creating a chain reaction. These pathways are incredibly organised - they're integrated, controlled, and many are interconnected like a complex network.
Some pathways are reversible (can go both ways) whilst others are irreversible (one-way only). Many also have alternative routes, like having multiple paths to the same destination. When pathways go wrong due to genetic mutations, you get conditions like phenylketonuria (PKU), where the body can't break down certain amino acids properly.
There are two main types of metabolic pathways: anabolic reactions build large molecules from small ones (requiring energy), whilst catabolic reactions break large molecules down into smaller ones (releasing energy). Think building up vs breaking down.
Key Point: Understanding that metabolic pathways are like organised assembly lines helps explain how your body coordinates thousands of chemical reactions efficiently.
