Photosynthesis

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Photosynthesis and nowthe details
11/13/06 Division II Kris Eli 2006-2007
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The Stages of Photosynthesis A Review Stage 1
- Energy is captured from sunlight. Stage 2 -
Light energy is converted to chemical energy,
which is temporarily stored in ATP and the energy
carrier molecule NADPH. Stage 3 - The chemical
energy stored in ATP and NADPH powers the
formation of organic compounds, using carbon
dioxide, CO2.
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Plant cells contain CHLOROPLASTS

• Chloroplasts have Chlorophyll (pigments)
• Pigments absorb the sunlight energy
• 2 Types of Chlorophyll
• chlorophyll a
• Chlorophyll b accessory pigment

Chlorophyll a Chlorophyll b
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What is Light?
Thats a tough one to explain
Remember how I said that energy can only be
observed by its effect on other objects?
Welllight energy can also only be explained by
the way it behaves under specific conditions
(i.e. in the laboratory).
The easiest way to describe light is by its
wave-like properties. Think of light like an
ocean wave, with troughs and peaks.
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Different Types of Light
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Colors

• We SEE what is REFLECTED

Example the wall is yellow because yellow is
reflected and all other colors are being absorbed.
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Lets put it all together
Light energy and plant pigments
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One more pigment type that is important
Carotenoids
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Carotenoids are important in capturing sunlight
as well and passing the energy on to the
cholorophyll to make sugars.
This movie will show you why carotenoids are
important in leaf color.
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Homework For Tuesday 11/14

• Review Figure 7-4 on page 127 of the reading
  packet
• Answer the following questions
• The solar energy needed to create the formation
  of ATP is absorbed by which photosystem?
• The high energy electrons that are released from
  the photosystem in question 1 are replaced by
  what reaction? Relate this answer to the overall
  photosynthesis reaction that should be in your
  notes.
• Put the following in order that they occur
• NADPH is synthesized from NADP and H and high
  energy electrons
• Photosystem I absorbs solar energy
• Energetic electrons are released into the
  electron transport chain and replaced in
  photosystem I by high energy electrons coming
  from photosystem II.