Photosynthesis
How plants make energy
1. Mesophyll
1. Mesophyll
A layer of cells that
contain chloroplasts &
are responsible for most
of the plant’s
photosynthesis
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O2
2. Stomata
Openings in plant leaves that
allow for gas exchange to occur
Carbon Dioxide (CO2) passes in
and Oxygen (O2) passes out.
CO2
Mesophyll Cell
Chloroplast
The site of Photosynthesis
Double-membrane
bound organelle
Outer membrane
Inner membrane
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8. Grana
7. Thylakoid
Chlorophyll
resides in these
membranes
6. Stroma
8. Grana
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Bond Energy and Energy
Storing Compounds
ATP, NADPH, FADH2, NADH
How is energy stored in organic
compounds?
• When bonds are made by dehydration
synthesis, energy is stored within the
bonds of the compounds.
How is energy released?
• When bonds are broken by hydrolysis,
energy is released from the bonds.
What are some examples of
common energy storing
compounds?
1. ATP (Most important usable energy for
the cell.)
2. NADPH
3. FADH2
4. NADH
How is ATP made?
• ATP is made from the precursor AMP
(Adenosine Mono-phosphate)
• If a phophate and energy is added to AMP,
ADP is created.
• Furthermore, if another phosphate is
added to ADP, ATP is created.
How ATP is Made
• AMP
A
P
• ADP
A
P
P
• ATP
A
P
P
P
Equation for ATP synthesis
• ADP + P + energy  ATP
How are NADPH, FADH2, and
NADH made?
•
•
•
•
NADP+ + H+ + electrons  NADPH
FAD+ + H+ + electrons  FADH2
NAD+ + H+ + electrons  NADH
Notice that high energy electrons and
hydrogen ions are needed to create
NADPH, FADH2 and NADH.
Draw and label the parts of the
chloroplast
Photosynthesis (definition)
• The making of food in the form of
_______________ (such as
glucose) by autotrophic
organisms by using sunlight,
____________ gas, and
_________________.
What are the two main steps of
photosynthesis?
1. ________________
2. ________________ Cycle
The Nature of Light
• In addition to
the wave-like
nature of light,
light consists of
discrete
particles called
photons .
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What happens in the light reaction?
•
•
Green ______________ pigment
embedded in the
________________________ captures
the light energy ____________ from the
sun.
____________(e-) are taken from
__________, and are excited to a higher
energy state by the light captured by the
chlorophyll pigment.
What happens in the light reaction?
•
•
•
A complex series of enzymatic reactions occur,
and ____ molecules of oxygen gas (O2) are
created as a waste product.
Meanwhile, the energy from the excited
electrons is used to create the compounds,
__ __ __ and __ __ __ __ __.
Both ATP and NADPH are high energy
compounds used to fuel the ____________
Cycle.
Summary of the Light Reaction
+
+
NADPH
++ +
+ 2e4e+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
ATP
What happens in the Calvin Cycle?
•
•
•
The energy from the ATP and NADPH is
released when their ___________ are broken.
The energy released from ATP and NADPH
starts another series of enzymatic reactions in
the ______________, where __CO2 gas is
captured and converted into monosaccharides
such as glucose (_____________).
Glucose serves as “food” or _________
energy for the plant.
PGAL
What is the overall chemical
equation for photosynthesis?
• __H2O
• (water)
• LR
• LR =
• CC =
+ __CO2 + sunlight  C6H12O6 + __O2
(carbon dioxide gas)
CC
(glucose)
+ (oxygen gas)
CC
LR
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Pathway of Photosynthesis
On your own, balance this equation:
6 CO2 + 6 H2O + (Light)  1 C6H12O6 + 6 O2
Reactants must equal Products
Carbon 6
Carbon 6
Hydrogen 12
Hydrogen 12
Oxygen 18
Oxygen 18