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Wize University Biology Textbook > Energy & Metabolism

Overview of Metabolism

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Overview of Metabolism

Metabolism is the collection of all chemical reactions that take place inside the cell.
  • Anabolism refers to the metabolic pathways that synthesize complex molecules from simpler ones, using up energy. Example: making glucose from photosynthesis; proteins from amino acids.
  • Catabolism refers to the metabolic pathways that break down complex molecules to simpler ones, releasing energy. Example: cellular respiration (breaking down glucose).



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Nutrients Required by Cells

Cells require several nutrients in order to engage in catabolic and anabolic processes.
  • Major bioelements (C, N, P, S, O, H)
  • Minor bioelements (Fe, Ca, Mg, Zn, etc.)
  • Vitamins
  • Electrons
  • Energy

Metabolic Classification

Organisms are grouped on the basis of their sources of energy, electrons, and carbon.



Practice: Organism Classifications

Describe the energy, electron and carbon source of the following organisms

a) Photoorganoheterotroph:

Energy source is (sunlight/ preformed molecules)
.
Electron donor is (organic/ inorganic)
compound.
Carbon source is (organic/ inorganic)
compound.


b) Chemolithoheterotroph:

Energy source is (sunlight/ preformed molecules)
.
Electron donor is (organic/ inorganic)
compound.
Carbon source is (organic/ inorganic)
compound.


Practice: Anabolism

Define anabolism:

Practice: Major Bioelements

Which one of the following is not a MAJOR bioelement?