BackMicrobial Metabolism: Enzymes, Energy, and Metabolic Pathways
Study Guide - Smart Notes
Tailored notes based on your materials, expanded with key definitions, examples, and context.
Chapter 5: Microbial Metabolism
Key Concepts
Enzymes and Energy Drive Cellular Metabolism
Glucose Catabolism Generates Cellular Energy
There Are Other Pathways to ATP Production
Photosynthesis Converts Light Energy to Chemical Energy
Microbes Exhibit Metabolic Diversity
Enzymes and Energy Drive Cellular Metabolism
Introduction to Metabolism
Metabolism encompasses all chemical reactions that occur within a microbe, enabling it to break down substances for energy and build new cellular components. The ultimate function of metabolism is to support the reproduction and survival of the organism.
Metabolic reactions are the controlled biochemical reactions within a cell.
A metabolite is any molecule that is a nutrient, intermediate, or end-product in a metabolic reaction.
Catabolism and Anabolism
Metabolic reactions are divided into two main categories: catabolism and anabolism.
Catabolism: The breakdown of larger molecules into smaller ones, releasing energy. These reactions are generally exergonic (energy-releasing).
Anabolism: The assembly of smaller molecules into larger, more complex molecules, requiring energy input. These reactions are endergonic (energy-consuming).
Energy released from catabolic reactions is often used to drive anabolic reactions.
Comparison of Catabolic and Anabolic Pathways
Feature | Catabolism | Anabolism |
|---|---|---|
Process | Breakdown of large molecules | Synthesis of larger molecules |
Products | Small molecules | Large molecules |
Energy | Released (exergonic) | Required (endergonic) |
Examples | Cellular respiration | Photosynthesis |
Enzyme mediation | Yes | Yes |
Summary Diagram
The diagram (not shown here) illustrates how catabolic pathways break down nutrients to release energy, which is then used by anabolic pathways to build macromolecules necessary for cell growth and reproduction.
Key Points
Catabolic pathways hydrolyze bonds to break larger molecules into smaller products, releasing energy.
Anabolic pathways synthesize large molecules from smaller products, trapping energy in new bonds.
Metabolism is a balance of catabolic and anabolic reactions, regulated to meet the cell's needs.
Example
Cellular respiration is a catabolic process that breaks down glucose to release energy.
Photosynthesis is an anabolic process that builds glucose from carbon dioxide and water using light energy.
