Outline of Campbell's Biology Text
As is typical of any open system, cells require outside energy
sources to perform cellular work (e.g. chemical, transport and
- Energy flows into the living world mostly as sunlight
- Photosynthetic organisms trap a portion of the light energy
and transform it into chemical bond energy of organic molecules
- Cells use some of the chemical bond energy in organic
molecules to make ATP - the energy source for cellular work
- Energy leaves living organisms as it dissipates as heat
How do cells harvest chemical energy?
Major Catabolic Pathways:
- Fermentation = Anaerobic catabolism of organic nutrients which
results in a partial degradation of organic molecules.
- Cellular respiration = Aerobic catabolism of organic of
organic nutrients which is the most prevalent and efficient
Chemical Recycling, the Carbon Cycle:
- The waste products of the major catabolic pathway,
respiration, are used as the raw materials for photosynthesis.
- Photosynthesis produces glucose and oxygen, the raw materials
- Although chemical elements essential for life are recycled,
energy is not.
To fully investigate the area of nutrient and energy cycling we
will examine respiration in this module and photosynthesis in the
next. The respiration module comprises the following sections. You
may click on the topics of choice.
- How cells produce cellular
energy: an Introduction
- Redox reactions in
- The Citric Acid Cycle (Kreb's
- The Electron Transport Chain and
- Fermentation: Anaerobic
- Comparison of Aerobic and anaerobic
- Catabolism of other
- Control of respiration.