3. 7.1 Photosynthesis and Life
• trap radiant energy from sunlight and convert it
into the energy of chemical bonds in large
molecules, such as carbohydrates,
• estimated 99.9% of life on Earth relies on
photosynthesis for its energy needs
5. Sunlight minus absorbed
wavelengths or colors equals
the apparent color of an
object.
The feathers of male cardinals are
loaded with carotenoid pigments.
These pigments absorb some
wavelengths of light and reflect
others.
7. WHY ARE PLANTS GREEN?
Plant Cells
have Green
Chloroplasts
The thylakoid
membrane of the
chloroplast is
impregnated with
photosynthetic
pigments (i.e.,
chlorophylls,
carotenoids).
8. 7.2 An Overview of Photosynthesis
• Chlorophyll: An important molecule in the process of harvesting
sunlight,
• light energy is transformed to chemical-bond energy in the form of
ATP,
9. 3 distinct events in the photosynthesis
• Light-capturing events,
• Light-dependent reactions,
• Light-independent reactions
10. Light-Capturing Events:
• Chlorophyll consists of
chlorophyll a and
chlorophyll b,
• Chlorophyll capture light
energy and become
excited,
11. Chloroplast Pigments
• Chloroplasts contain several pigments
– Chlorophyll a
– Chlorophyll b
– Carotenoids
Figure 7.7
12. Chlorophyll a & b
•Chl a has a methyl
group
•Chl b has a carbonyl
group
Porphyrin ring
delocalized e-
Phytol tail