Metabolism and Energy of
Cell
Part 2- Photosynthesis
,Photosynthesis: Capturing Light Energy
• Plants capture light energy and fix CO2 by photosynthesis, the
sequence of events by which light energy is converted into the stor
chemical energy of organic molecules.
• Photosynthesis is the first step in the flow of energy through most
the living world, capturing the vast majority of the energy that livin
organisms use.
• Photosynthesis not only sustains plants and other photosynthetic
organisms such as algae and photosynthetic bacteria but also
indirectly supports most nonphotosynthetic organisms such as
animals, fungi, protozoa, and most bacteria.
,Light and photosynthesis
• Light is composed of small particles, or packets, of energy called
photons.
• The energy of a photon is inversely proportional to its wavelength:
shorter-wavelength light has more energy per photon than longer-
wavelength light.
• Visible light has just the right amount of energy to cause the kinds
reversible changes in molecules that are useful in photosynthesis.
• Radiation with wavelengths shorter than those of visible light is so
energetic that it disrupts the bonds of many biological molecules.
,
Cell
Part 2- Photosynthesis
,Photosynthesis: Capturing Light Energy
• Plants capture light energy and fix CO2 by photosynthesis, the
sequence of events by which light energy is converted into the stor
chemical energy of organic molecules.
• Photosynthesis is the first step in the flow of energy through most
the living world, capturing the vast majority of the energy that livin
organisms use.
• Photosynthesis not only sustains plants and other photosynthetic
organisms such as algae and photosynthetic bacteria but also
indirectly supports most nonphotosynthetic organisms such as
animals, fungi, protozoa, and most bacteria.
,Light and photosynthesis
• Light is composed of small particles, or packets, of energy called
photons.
• The energy of a photon is inversely proportional to its wavelength:
shorter-wavelength light has more energy per photon than longer-
wavelength light.
• Visible light has just the right amount of energy to cause the kinds
reversible changes in molecules that are useful in photosynthesis.
• Radiation with wavelengths shorter than those of visible light is so
energetic that it disrupts the bonds of many biological molecules.
,
