1. ATP (Adenosine Triphosphate):
* Universal Energy Currency: This is the primary energy storage molecule for all living organisms, including bacteria.
* Production: Bacteria produce ATP through various processes, including:
* Glycolysis: The breakdown of sugars like glucose into pyruvate, producing a small amount of ATP.
* Krebs Cycle (Citric Acid Cycle): Further breakdown of pyruvate, generating more ATP and electron carriers.
* Electron Transport Chain: A series of protein complexes that use electron carriers (NADH, FADH2) to pump protons across a membrane, creating a proton gradient that drives ATP synthesis.
2. Polyphosphate Granules:
* Inorganic Phosphate Storage: These granules are composed of long chains of inorganic phosphate molecules.
* Function: Act as a readily available energy reserve, providing energy for various cellular functions, including the synthesis of ATP and biosynthesis.
3. Glycogen:
* Glucose Polymer: Some bacteria store energy as glycogen, a branched polymer of glucose.
* Function: Similar to polyphosphate granules, glycogen serves as a readily available energy source, particularly when glucose levels are low.
4. Lipids (Fatty Acids):
* High Energy Storage: Bacteria can store energy in the form of lipids, particularly fatty acids.
* Function: Lipids provide a long-term energy reserve, often used when other energy sources are depleted.
5. Other Forms:
* Sulfur Granules: Some bacteria, particularly those that use sulfur as an electron donor, store energy in the form of sulfur granules.
* Carbon Storage: Bacteria like cyanobacteria can store energy as carbon compounds, particularly during photosynthesis.
It's important to note that different bacteria utilize these energy storage mechanisms to varying degrees, depending on their specific metabolic needs and environmental conditions.
