8.1: Metabolism
Mission 1: MetaboLIFE!
Mission Objectives. You should be able to...
1. Describe metabolic pathways in simple terms.
2. Explain the function of enzymes.
3. Describe the difference between competitive and non-competitive inhibitors.
4. Distinguish between different types of inhibition from graphs at specified substrate concentrations.
5. Calculate and plot rates of reaction from raw experimental results.
Mission Objectives. You should be able to...
1. Describe metabolic pathways in simple terms.
2. Explain the function of enzymes.
3. Describe the difference between competitive and non-competitive inhibitors.
4. Distinguish between different types of inhibition from graphs at specified substrate concentrations.
5. Calculate and plot rates of reaction from raw experimental results.
Metabolic Pathways. Almost all metabolic reactions are catalyzed by enzymes. They occur in specific sequences and are called metabolic or biochemical pathways. Examine the figure below. Each arrow represents a specific enzyme that causes a substrate to be changed into something else until the final product is formed. Some pathways consist of reaction cycles rather than chains. Others require both. Metabolic pathways are carried out in designated compartments of the cell where the necessary enzymes tend to hang out.
Competitive/Noncompetitive Inhibition. Competitive inhibitors compete directly with the usual substrate for the active site on an enzyme. The end result is that the rate of the chemical reaction is reduced because there are fewer collisions between the substrate and the active site. Noncompetitive inhibitors do not compete with the substrate for the active site. Rather, the inhibitor reacts with another site on the enzyme and changes the shape of the active site, making it non-functional. Noncompetitive inhibitors are also called allosteric inhibitors. See below.