This document discusses several ways that environmental factors and molecules can affect enzyme activity and metabolic pathways. It notes that enzyme saturation occurs when substrate concentration builds up to a maximum level, increasing the final product. Temperature and pH can also impact the rate of enzymatic reactions. Allosteric enzymes can be inhibited or activated by certain molecules to control when the enzyme is active. Competitive inhibition involves substrate molecules blocking the active site. Metabolic pathways involve a series of enzyme-catalyzed reactions to produce new molecules, and feedback inhibition allows pathways to regulate themselves based on end product levels.
