harvesting energy Flashcards
most common fuel in organisms
glucose
Conversion follows metabolic pathway
Principles governing metabolic pathways:
Chemical transformations occur in a series of reactions
Each reaction is catalyzed by a specific enzyme
Metabolic pathways are similar in all organisms
In eukaryotes, metabolic pathways are compartmentalized in organelles
Each pathway is regulated by key enzymes
Glucose is the most common chemical fuel for non-photosynthetic organisms
Energy is transferred by
Oxidation-Reduction reaction or Redox reactions
Oxidation-Reduction reaction or Redox reactions
in which one substance transfer electrons to other substance
oxidation and reduction
Reduction: Gain of one or more electrons by an atom, ion, or molecule
Oxidation: Loss of one or more electrons
Energy is transferred in a redox reaction.
glucose is the reducing agent(oxidized),
O2 is the oxidizing agent(reduced).
Coenzyme NAD+
electron carrier in redox reactions.
NAD+
- carrier molecule
- traps (e-) and protons(H+)
- transfer (e-) and (H+) where they need in a cell
Glucose metabolism pathway; traps the free energy into ATP
ATP: movement of muscles or active transport across membranes
Three metabolic processes are involved; in harvesting the energy of glucose
- Glycolysis
- If O2 present: Cellular respiration
- If O2 absent: Fermentation
Glycolysis—glucose is converted to pyruvate through a series of chemical rearrangements
If O2 present: Cellular respiration— conversion of pyruvate to ATP, H2O, & CO2
If O2 absent: Fermentation—and conversion of pyruvate into ATP, lactic acid or ethanol, and CO2 – releases less energy
If O2 is present glycolysis is followed by three pathways of cellular respiration:
- Pyruvate oxidation
- Citric acid cycle
- Electron transport chain
