Photosynthesis
The Photosynthesis Song http://www.youtube.com/watch?v=C1_uez5W
X1o
Intro Video –
http://www.youtube.com/watch?v=zEgIO9Kq
2_Y
Photosynthesis
Photosynthesis the Movie http://vcell.ndsu.nodak.edu/animations/photos
ynthesis/movie.htm
Objectives
1. Summarize how energy is captured from sunlight
during the light dependent reactions of
photosynthesis.
2. Analyze the function of electron transport chains
during the light dependent reactions of
photosynthesis.
3. Relate the Calvin cycle to carbon dioxide
fixation in photosynthesis.
4. Identify three environmental factors that affect
the rate of photosynthesis.
Stages of Photosynthesis
Stage 1 Light-dependent reaction
Chlorophyll pigments capture light energy
Stage 2 Light-dependent reaction
Thylakoid
membranes
Light energy converted to chemical energy.
Production of ATP and NADPH
Stage 3 Light-independent reaction
Reduction of CO2 to glucose:
using ATP + NADPH + H+ to synthesize
organic compounds (glucose) from CO2
(carbon fixation); process called Calvin cycle;
© Teachable and Louise Edgeworth. Some rights reserved. http://teachable.net/res.asp?r=6615
Stroma
The Dark Side

You just made a bunch of ATP and NADPH from
the light reactions.
You now use these electrons and energy to put a
bunch of carbons together to make glucose – this
is the job of the Calvin cycle.
The Calvin cycle can be broken down into three
phases:


1.
2.
3.
Carbon fixation – Putting carbons together.
Reduction reactions – Adding electrons & energy.
Regeneration of RuBP – Getting back to the start – it
is a cycle after all.
The Calvin Cycle!
What is it?
The Calvin Cycle
uses ATP and
NADPH from the
light-dependent
reactions and CO2
from the air to make
high-energy sugars
(glucose)!
Glucose
Where does the Calvin Cycle occur?
The Calvin Cycle occurs in the stroma of the
chloroplast.
What parts of the photosynthesis equation
are involved in the Calvin Cycle?
CO2 is broken
down to create
glucose
(C6H12O6)
C6H12O6
Steps of the Calvin Cycle
Calvin Cycle – Carbon Fixation
1. Six CO2 molecules enter the leaf through the stoma and
diffuse into the stroma. They are added to a 5 carbon
compound (ribulose biphosphate (RuBP)) by an enzyme
(rubisco – ribulose bisphosphate carboxylase).
Calvin Cycle – Carbon Fixation
2. They are split
into twelve 3carbon
compounds
3. ( 3phosphoglycerate
(PGA)).
Calvin Cycle – Reduction Reactions
3. Energy from ATP is
used to
phosphorylate the 3carbon compounds
(PGA) into 1,3biphosphoglycerate
4. A pair of electrons
from NADPH
reduces the 1,3biphosphoglycerate
to give G3P –
glyceraldehyde 3phosphate., a 3C
Calvin Cycle – Regeneration of RuBP
4. Two of the resulting 3-carbon sugars is used to
make organic compounds – including GLUCOSE,
starch and sucrose – in which energy is stored for
later use by the organism.
Calvin Cycle – Regeneration of RuBP
5. The other ten 3-carbon sugars are used to regenerate the initial 5carbon compound, (RuBP) thereby completing the cycle. This
Review of Calvin Cycle
Where does the Calvin Cycle
occur?
 In the stroma of the chloroplast!
What goes into the Calvin Cycle?
 ATP and NADPH are used for energy
 CO2 is broken apart to create C6H12O6
Animation of Overview of
Photosynthesis
 http://wps.prenhall.com/wps/media/objects/
486/498596/CDA7_1/CDA7_1d/CDA7_1d.
htm
Factors that
Affect
Photosynthesis
Photosynthesis is directly
affected by environmental
factors such as:
1. The intensity of light
2. The concentration of
carbon dioxide
3. Temperature.
PHOTOSYNTHESIS QUIZ
1.
2.
3.
4.
5.
6.
7.
15 points
Where in a plant cell does photosynthesis occur?
What are the 2 stages of photosynthesis and where do
they occur?
Why are plants green?
What is the balanced equation for photosynthesis?
What are the reactants and products of the light
dependent reactions?
What are the reactants and products of the Calvin
Cycle?
What are two reasons we depend on plants for our
survival?
Review
1. Summarize how photosynthetic organisms
capture the energy in sunlight.
2. Compare the roles of water molecules and
hydrogen ions in electron transport chains.
3. Describe the role of the Calvin cycle in
photosynthesis.
4. Critical Thinking Organizing Information
Make a table in which you identify the role of
each of the following in photosynthesis: light,
water, pigments. ATP. NADPH. and carbon
dioxide.
5. Critical Thinking Inferring
Relationships What combination of
environmental factors affects the rate of
photosynthesis?
6. Standardized Test Prep During
photosynthesis, plants store energy in
A ADP.
B carbon dioxide.
C 3-carbon sugars.
D water.