Microbial Metabolism Basics Flashcards
The entire set of life-sustaining reactions within living organisms
Metabolism
The degradation of biopolymers into a small number of intermediates
Catabolism
The synthesis of intermediates into biopolymers
Anabolism
Cellular Respiration
The pathway in cells utilizing glycolysis, TCA cycle, and the ETC
Fermentation
The pathway in cells that uses glycolysis and fermentative pathways
Phosphorylation Types
Substrate-level phosphorylation: transfer of a phosphate to an ADP in a chemical reaction
Oxidative phosphorylation: energy stored in reducing power is oxidized at the ETC to generate ATP
Glycolysis
- Uses 2 ATP
- Starting: Glucose
- Ending: 2 Pyruvate
- Generates 4 ATP: 1, 3, and 7 (x2)
- Generates 2 NADH: 6 (x2)
Transition Step in Respiration
- Pyruvate decarboxylated to Acetyl CoA
- Generates 1 NADH
TCA
-Starts with Acetyl-CoA (or pyruvate)
-Ends by regenerating oxaloacetate
For two cycles:
-2 ATP: 5 (x2)
-8 NADH: 0,3,4,8 (x2)
-2 FADH2: 6 (x2)
-6 CO2: 0,3,4 (x2)
Reducing power ATP equivalents
NADH = 3 ATP FADH2 = 2 ATP
Electron Transport Chain
- NADH and FADH2 transfer electrons through carrier molecules
- Electrons transfer to terminal electron carrier with concurrent proton transfer
- As electrons move down the chain, protons are pumped into periplasmic/intermembrane space
Chemiosmotic Theory
- Energy generation in biological systems is driven by proton gradients across membranes
- pH, charge, and concentration gradient create energized membrane, which is relieved through ATP generation
Net ATP produced per glucose
Glycolysis (2 ATP + 2 NADH)
TCA (2 ATP + 8 NADH + 2 FADH2)
Total: 38 ATP
ATP Yield Variance
- Organisms have different ETC systems for different conditions
- Yield varies based on final electron acceptor
