Chapter 9: Overview of Metabolism Flashcards
Metabolism
- Process by which organisms generate and use free energy to perform essential functions
Intermediary metabolism reactions involve
- Small, low molecular weight molecules
Commonalities exhibited by cells
- Maintain constant internal environment
- Use energy from environment to drive rxns
- Reproduce /grow
- Respond to external stimuli
Metabolic reactions defined
- Series of metabolic steps
- Facilitate the harnessing of energy
Common reaction types in metabolic pathways
- Reciprocal regulation
- Can be linear, spiral, or cyclic
Convergent metabolsim
- Catabolism
Divergent metabolism
- Anabolism
Complete oxidation of glucose releases
- 3000kj/mol of energy
Pyruvate dehydrogenase enzyme controlled by
- Reversible phosphorylation
- Tightly controlled system
Catabolism depends on
- Fuel
- Presence/absence of oxygen
Anabolsim depends on
- Biosynthetic requirements
- Input of energy
Amphibolic reactions
- Both catabolic and anabolic
Biosynthesis/cholesterol/FA synthesis involves
- NADPH
Energy/ETC/production of ATP involves
- NADH
Substrate cycling
- Independent regulation of anabolic and catabolic pathways
Catabolism
- Produces energy
- Oxidative breakdown of large macromolecules
- Exergonic (release energy in the form of ATP)
3 stages of aerobic catabolism
- Large molecules > smaller
- Further degraded > pyruvate or Acetyl-SCoA (so they can enter CAC)
- CAC and oxidative phosphorylation (final step)
Final stage of carbohydrate and fat metabolism
- Same step
- CAC and ETC
Catabolsim converges on
- Acetyl-SCoA
Anabolsim
- Biosynthetic
- Formation of large macromolecules
- Endergonic (requires energy input)
Anabolism considered divergent
- Produces wide array of products from a small number of metabolites
Important metabolic intermediates present in more than one pathway
- Glucose-6-phosphate
- Pyruvate
- Acetyl-SCoA
- All are bridges between anabolic and catabolic pathways
