Biology
Slide
1 of 51
Copyright Pearson Prentice Hall
8-3 The Reactions of
Photosynthesis
Slide
2 of 51
Copyright Pearson Prentice Hall
8-3 The Reactions of Photosynthesis
Inside a Chloroplast
1. In plants, photosynthesis takes place inside
chloroplasts.
Plant
Chloroplast
Plant cells
Slide
3 of 51
Copyright Pearson Prentice Hall
8-3 The Reactions of Photosynthesis
Inside a Chloroplast
2. thylakoids—saclike photosynthetic membranes
*Inside a Chloroplast
.
Single
thylakoid
Chloroplast
Copyright Pearson Prentice Hall
Slide
4 of 51
8-3 The Reactions of Photosynthesis
Inside a Chloroplast
3. Grana: stack of thylakoids
(A singular stack is called a granum.)
Granum
Chloroplast
Copyright Pearson Prentice Hall
Slide
5 of 51
8-3 The Reactions of Photosynthesis
Inside a Chloroplast
4. photosystems: the light-collecting units of the
chloroplast.
Photosystems
Chloroplast
Copyright Pearson Prentice Hall
Slide
6 of 51
8-3 The Reactions of Photosynthesis
Inside a Chloroplast
5. The reactions of photosystems include:
a. light-dependent reactions
*takes place within thylakoid membranes
b. light-independent reactions, or Calvin
cycle.
*takes place in the stroma, which is the
region outside the thylakoid membranes.
Slide
7 of 51
Copyright Pearson Prentice Hall
8-3 The Reactions of Photosynthesis
H 2O
Inside a Chloroplast
CO2
Light
NADP+
ADP + P
Lightdependent
reactions
Calvin
Calvin
cycle
Cycle
Chloroplast
Sugars
O2
Copyright Pearson Prentice Hall
Slide
8 of 51
8-3 The Reactions of Photosynthesis
Electron Carriers
6. Electron Carriers
Transport high-energy electrons from chlorophyll
to other molecules.
a. NADP+: transports H+ electrons;
converts into NADPH
*used to help build variety of molecules
the cell needs (carbohydrates)
Slide
9 of 51
Copyright Pearson Prentice Hall
8-3 The Reactions of Photosynthesis
Light-Dependent
Reactions
7. Light-Dependent Reactions
a.  The light-dependent reactions require
light.
b.  produce oxygen gas
c. converts ADP into ATP
d. NADP+ into NADPH.
Slide
10 of 51
Copyright Pearson Prentice Hall
8-3 The Reactions of Photosynthesis
Light-Dependent
Reactions
(The light-dependent reactions use water, ADP, and
NADP+.
The light-dependent reactions produce oxygen, ATP,
and NADPH.
These compounds provide the energy to build
energy-containing sugars from low-energy
compounds.)
Slide
11 of 51
Copyright Pearson Prentice Hall
8-3 The Reactions of Photosynthesis
The Calvin Cycle
8.The Calvin Cycle (Light Independent
Reaction)
(ATP and NADPH formed by the light-dependent
reactions contain an abundance of chemical
energy, but they are not stable enough to store that
energy for more than a few minutes.
During the Calvin cycle plants use the energy that
ATP and NADPH contain to build high-energy
compounds that can be stored for a long time.)
Slide
12 of 51
Copyright Pearson Prentice Hall
8-3 The Reactions of Photosynthesis
The Calvin Cycle
a. The Calvin cycle uses ATP and NADPH
from the light-dependent reactions to
produce high-energy sugars.
b. Calvin cycle does not require light
Slide
13 of 51
Copyright Pearson Prentice Hall
8-3 The Reactions of Photosynthesis
The Calvin Cycle
9. The two sets of photosynthetic reactions work
together.
•  The light-dependent reactions trap sunlight
energy in chemical form.
•  The light-independent reactions use that
chemical energy to produce stable, highenergy sugars from carbon dioxide and water.
Slide
14 of 51
Copyright Pearson Prentice Hall
8-3 The Reactions of Photosynthesis
Factors Affecting
Photosynthesis
10. Many factors affect the rate of photosynthesis,
including:
• Water
• Temperature
• Intensity of light
Slide
15 of 51
Copyright Pearson Prentice Hall
8-3
Click to Launch:
Continue to:
- or -
Slide
16 of 51
Copyright Pearson Prentice Hall
8-3
In plants, photosynthesis takes place inside the
a.  thylakoids.
b.  chloroplasts.
c.  photosystems.
d.  chlorophyll.
Slide
17 of 51
Copyright Pearson Prentice Hall
8-3
Energy to make ATP in the chloroplast comes
most directly from
a.  hydrogen ions flowing through an enzyme in
the thylakoid membrane.
b.  transfer of a phosphate from ADP.
c.  electrons moving through the electron
transport chain.
d.  electrons transferred directly from NADPH.
Slide
18 of 51
Copyright Pearson Prentice Hall
8-3
NADPH is produced in light-dependent reactions
and carries energy in the form of
a.  ATP.
b.  high-energy electrons.
c.  low-energy electrons.
d.  ADP.
Slide
19 of 51
Copyright Pearson Prentice Hall
8-3
What is another name for the Calvin cycle?
a.  light-dependent reactions
b.  light-independent reactions
c.  electron transport chain
d.  photosynthesis
Slide
20 of 51
Copyright Pearson Prentice Hall
8-3
Which of the following factors does NOT directly
affect photosynthesis?
a.  wind
b.  water supply
c.  temperature
d.  light intensity
Slide
21 of 51
Copyright Pearson Prentice Hall
END OF SECTION