AP Biology
John D. O’Bryant School of
Mathematics and Science
November 6, 2012
AP Biology
Agenda
 Do Now (Table of Contents)
 HW discussion; Lab discussion
 Photosynthesis: Modeling
AP Biology
Quiz






ATP and NADPH
A) play a role in glucose synthesis by plants.
B) are products of the Calvin cycle.
C) are inputs to the photosystems.
D) production is associated with events taking place
on the inner mitochondrial membrane.
E) are used in the electron transport chain to pump H+
into the thylakoid space.
AP Biology
Quiz
 2. The chloroplast ATP synthase
 A) is a nucleic acid complex.
 B) transports H+ ions from the stroma to the thylakoid
space.
 C) couples the flow of H+ to the phosphorylation of NADP+.
 D) is embedded in the inner membrane of the chloroplast.
 E) helps transport H+ against the concentration gradient.
AP Biology
Quiz
 3. Some photosynthetic bacteria (e.g., purple sulfur
bacteria) have photosystem I but not II, while others (e.g.
cyanobacteria) have both PSI and PSII. Which of the
following might this observation imply?

A) Photosystem II must have been selected against in some
species.
B) Photosystem I must be more ancestral.
C) Photosystem II may have evolved to be more
photoprotective.
D) Cyclic flow must be more primitive than linear flow of
electrons.
E) Cyclic flow must be the most necessary of the two
processes.
AP Biology
Quiz
 4. Which of the following requires glucose?

A) light reactions alone
B) the Calvin cycle alone
C) both the light reactions and the Calvin cycle
D) neither the light reactions nor the Calvin cycle
E) photophosphorylation
AP Biology
Quiz
 5. Which of the following sequences correctly
represents the flow of electrons during
photosynthesis?

A) NADPH → O2 → CO2
B) H2O → NADPH → Calvin cycle C) NADPH →
chlorophyll → Calvin cycle
D) H2O → photosystem I → photosystem II
E) NADPH → electron transport chain → O2

AP Biology
Table of Contents
(Notes/Classwork)
Date
Topic
11/1/12
Cellular Respiration summary; Photosynthesis:
Overview
11/2/12
Photosynthesis: Overview, Light Reactions;
Pigment lab
11/5/12
Photosynthesis: Calvin Cycle, Light Reactions
11/6/12
Photosynthesis: Modeling
Page
number
HW
1. Discuss the possible effects of the following on photosynthesis:
 i) chloroplast with a leaky outer membrane
 ii) chloroplast with a leaky thylakoid membrane
 iii) an increase in the amount of carbon dioxide in the atmosphere
 iv) a decrease in the amount of available sunlight
 v) an increase in the amount of water vapor in the atmosphere
2. Describe the experiment that was done by scientists to figure out whether the oxygen
gas produced during photosynthesis came from carbon dioxide or water.
3. Create a flow diagram (concept map) showing the sequence of events during
photophosphorylation. Include both cyclic and noncyclic flow.
4. In the mid-1600s, the Belgian physician and chemist Jan Baptista van Helmont grew a
small willow tree in a pot, adding only water to the soil. After five years, he found that the
soil in the pot had lost only 60 grams, while the tree had grown by nearly 75 kilograms –
more than 1,000 times the material lost from the soil. Van Helmont concluded that the
tree had gained most of its substance not from the soil, but rather from the water he
supplied. Was van Helmont right? Explain.
AP Biology
Modeling Photosynthesis
Task:
In pairs, build a dynamic model of C3 photosynthesis using cutout pieces
of paper to represent the molecules, ions, and membrane transporters or
pumps. You should be able to manipulate or move carbon dioxide and
water and its breakdown products through the various steps of the
process.
AP Biology
AP Biology
2007-2008
Photosynthesis:
Life from Light and Air
AP Biology
2007-2008
chlorophyll a
ETC of Photosynthesis
Photosystem II
chlorophyll b
Photosystem I
AP Biology
ETC of Photosynthesis
sun
1
e
e
AP Biology
Photosystem II
P680
chlorophyll a
Inhale, baby!
ETC of Photosynthesis
thylakoid
chloroplast
+H+ H+ H+
+ + +
H+ H+H
+H+ H H H
H
H+
ATP
+H+ H+ H+
+
H
H + + H+H+ H+
HH
Plants SPLIT water!
H H
1
O
H
e-
e e
fill the e– vacancy
AP Biology
Photosystem II
P680
chlorophyll a
H+
e-
+H
OO
e
e
H
2
ETC of Photosynthesis
thylakoid
chloroplast
H+
+H+ H+ H+
+
H
H + + H+H+ H+
HH
+H+ H+ H+
H+ H+H
+ + + +
H+H H H H
ATP
3
2
1
e
e
H+
4
ATP
H+
to Calvin Cycle
H+
H+
H+
AP Biology
Photosystem II
P680
chlorophyll a
H+
H+
+
H+ H
ADP + Pi
ATP
H+
H+
energy to build
carbohydrates
ETC of Photosynthesis
e
e
5
e e
AP Biology
Photosystem II
P680
chlorophyll a
Photosystem I
P700
chlorophyll b
sun
ETC of Photosynthesis
electron carrier
6
e
e
5
sun
AP Biology
Photosystem II
P680
chlorophyll a
Photosystem I
P700
chlorophyll b
$$ in the bank…
reducing power!
ETC of Photosynthesis
sun
sun
+
+
+ H
H
+
+
H+ H +
H H
H+H+ H+ H
+
H
to Calvin Cycle
O
split H2O
ATP
AP Biology
ETC of Photosynthesis
 ETC uses light energy to produce

ATP & NADPH
 go to Calvin cycle
 PS II absorbs light



AP Biology
excited electron passes from chlorophyll to
“primary electron acceptor”
need to replace electron in chlorophyll
enzyme extracts electrons from H2O &
supplies them to chlorophyll
 splits H2O
 O combines with another O to form O2
 O2 released to atmosphere
 and we breathe easier!
Experimental evidence
 Where did the O2 come from?

radioactive tracer = O18
Experiment 1
6CO2 + 6H2O + light  C6H12O6 + 6O2
energy
Experiment 2
6CO2 + 6H2O + light  C6H12O6 + 6O2
energy
Proved O2 came from H2O not CO2 = plants split H2O!
AP Biology
Noncyclic Photophosphorylation
 Light reactions elevate
electrons in
2 steps (PS II & PS I)

PS II generates
energy as ATP

PS I generates
reducing power as NADPH
ATP
AP Biology
Cyclic photophosphorylation
 If PS I can’t pass electron
to NADP…it cycles back
to PS II & makes more
ATP, but no NADPH
coordinates light
reactions to Calvin cycle
 Calvin cycle uses more
ATP than NADPH


18 ATP +
NADPH
AP12
Biology
 1 C6H12O6
ATP
Photophosphorylation
cyclic
photophosphorylation
NADP
NONcyclic
photophosphorylation
ATP
AP Biology
Photosynthesis summary
Where did the energy come from?
Where did the electrons come from?
Where did the H2O come from?
Where did the O2 come from?
Where did the O2 go?
Where did the H+ come from?
Where did the ATP come from?
What will the ATP be used for?
Where did the NADPH come from?
What will the NADPH be used for?
AP Biology
…stay tuned for the Calvin cycle
Photosynthesis summary
Where did the energy come from? Sun (photons)
Where did the electrons come from?
Where did the H2O come from?
Where did the O2 come from?
Where did the O2 go?
Where did the H+ come from?
Where did the ATP come from?
What will the ATP be used for?
Where did the NADPH come from?
What will the NADPH be used for?
AP Biology
…stay tuned for the Calvin cycle
Photosynthesis summary
Where did the energy come from? Sun (photons)
Where did the electrons come from? H2O (H+)
Where did the H2O come from?
Where did the O2 come from?
Where did the O2 go?
Where did the H+ come from?
Where did the ATP come from?
What will the ATP be used for?
Where did the NADPH come from?
What will the NADPH be used for?
AP Biology
…stay tuned for the Calvin cycle
Photosynthesis summary
Where did the energy come from? Sun (photons)
Where did the electrons come from? H2O (H+)
Where did the H2O come from? Environment
Where did the O2 come from?
Where did the O2 go?
Where did the H+ come from?
Where did the ATP come from?
What will the ATP be used for?
Where did the NADPH come from?
What will the NADPH be used for?
AP Biology
…stay tuned for the Calvin cycle
Photosynthesis summary
Where did the energy come from? Sun (photons)
Where did the electrons come from? H2O (H+)
Where did the H2O come from? Environment
Where did the O2 come from? (Splitting of) H2O
Where did the O2 go?
Where did the H+ come from?
Where did the ATP come from?
What will the ATP be used for?
Where did the NADPH come from?
What will the NADPH be used for?
AP Biology
…stay tuned for the Calvin cycle
Photosynthesis summary
Where did the energy come from? Sun (photons)
Where did the electrons come from? H2O (H+)
Where did the H2O come from? Environment
Where did the O2 come from? (Splitting of) H2O
Where did the O2 go? Diffuses out through stomata
Where did the H+ come from?
Where did the ATP come from?
What will the ATP be used for?
Where did the NADPH come from?
What will the NADPH be used for?
AP Biology
…stay tuned for the Calvin cycle
Photosynthesis summary
Where did the energy come from? Sun (photons)
Where did the electrons come from? H2O (H+)
Where did the H2O come from? Environment
Where did the O2 come from? (Splitting of) H2O
Where did the O2 go? Diffuses out through stomata
Where did the H+ come from? (Splitting of) H2O
Where did the ATP come from?
What will the ATP be used for?
Where did the NADPH come from?
What will the NADPH be used for?
AP Biology
…stay tuned for the Calvin cycle
Photosynthesis summary
Where did the energy come from? Sun (photons)
Where did the electrons come from? H2O (H+)
Where did the H2O come from? Environment
Where did the O2 come from? (Splitting of) H2O
Where did the O2 go? Diffuses out through stomata
Where did the H+ come from? (Splitting of) H2O
Where did the ATP come from? ETC
What will the ATP be used for?
Where did the NADPH come from?
What will the NADPH be used for?
AP Biology
…stay tuned for the Calvin cycle
Photosynthesis summary
Where did the energy come from? Sun (photons)
Where did the electrons come from? H2O (H+)
Where did the H2O come from? Environment
Where did the O2 come from? (Splitting of) H2O
Where did the O2 go? Diffuses out through stomata
Where did the H+ come from? (Splitting of) H2O
Where did the ATP come from? ETC
What will the ATP be used for? Calvin Cycle
Where did the NADPH come from?
What will the NADPH be used for?
AP Biology
…stay tuned for the Calvin cycle
Photosynthesis summary
Where did the energy come from? Sun (photons)
Where did the electrons come from? H2O (H+)
Where did the H2O come from? Environment
Where did the O2 come from? (Splitting of) H2O
Where did the O2 go? Diffuses out through stomata
Where did the H+ come from? (Splitting of) H2O
Where did the ATP come from? ETC
What will the ATP be used for? Calvin Cycle
Where did the NADPH come from? Light reactions
What will the NADPH be used for?
AP Biology
…stay tuned for the Calvin cycle
Photosynthesis summary
Where did the energy come from? Sun (photons)
Where did the electrons come from? H2O (H+)
Where did the H2O come from? Environment
Where did the O2 come from? (Splitting of) H2O
Where did the O2 go? Diffuses out through stomata
Where did the H+ come from? (Splitting of) H2O
Where did the ATP come from? ETC
What will the ATP be used for? Calvin Cycle
Where did the NADPH come from? Light reactions
What will the NADPH be used for? Calvin Cycle
AP Biology
…stay tuned for the Calvin cycle
You can grow if you
Ask Questions!
AP Biology
2007-2008
Ghosts of Lectures Past
(storage)
AP Biology
2007-2008
Stomates
AP Biology
Photosynthesis:
The Calvin Cycle
Life from Air
AP Biology
2007-2008
Whoops!
Wrong
Calvin…
The
Calvin
Cycle
AP Biology
1950s | 1961
Remember what it means to be a plant…
 Need to produce all organic molecules
necessary for growth

carbohydrates, lipids, proteins, nucleic acids
 Need to store chemical energy (ATP)
produced from light reactions
in a more stable form
 that can be moved around plant
 saved for a rainy day

carbon + water + energy  glucose + oxygen
dioxide
light  C H O + 6O
AP Biology6CO2 + 6H2O +
6 12 6
2
energy
Light reactions
 Convert solar energy to chemical
energy
ATP

ATP  energy

NADPH  reducing power
 What can we do now?
  build stuff !!
AP Biology
photosynthesis
How is that helpful?
 Want to make C6H12O6
synthesis
 How? From what?
What raw materials are available?

CO2
NADPH
carbon fixation
reduces CO2
NADP
C6H12O6
AP Biology
NADP
From CO2  C6H12O6
 CO2 has very little chemical energy

fully oxidized
 C6H12O6 contains a lot of chemical energy

highly reduced
 Synthesis = endergonic process

put in a lot of energy
 Reduction of CO2  C6H12O6 proceeds in
many small uphill steps
each catalyzed by a specific enzyme
 using energy stored in ATP & NADPH

AP Biology
From Light reactions to Calvin cycle
 Calvin cycle

chloroplast stroma
 Need products of light reactions to
drive synthesis reactions
stroma
ATP
 NADPH

ATP
thylakoid
AP Biology
C
C
Calvin cycle
C C C C C
1C
C C C C C
3. Regeneration
C C C C C
of RuBP
RuBP
starch,
sucrose,
cellulose
& more
ribulose bisphosphate
3 ATP
H H H
|
| |
C–C–C
AP Biology
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
CO2
1. Carbon fixation
C C C C C C
RuBisCo
ribulose
bisphosphate
carboxylase
3 ADP
used
to make
glucose
C=C=C
5C
C
C C C C C C
6C
C C C C C C
5C
glyceraldehyde-3-P
G3P
C C C
PGA
phosphoglycerate
3C
6 NADP
C
C
C
C
C
C
6 ATP
2. Reduction
6 NADPH
3C
C
C
C
C
C
C
3C
6 ADP
C
C
C
C
C
C
H
|
H
|
H
|
Remember
G3P?
glycolysis
glucose
C-C-C-C-C-C
2 ATP
2 ADP
fructose-1,6bP
P-C-C-C-C-C-C-P
DHAP
P-C-C-C
G3P
glyceraldehyde
3-phosphate
C-C-C-P
2 NAD+
2
4 ADP
AP Biology
Photosynthesis
pyruvate
C-C-C
4 ATP
To G3P and Beyond!
 Glyceraldehyde-3-P
To G3P
and beyond!
end product of Calvin cycle
 energy rich 3 carbon sugar
 “C3 photosynthesis”

 G3P is an important intermediate
 G3P   glucose   carbohydrates
  lipids   phospholipids, fats, waxes
  amino acids   proteins
  nucleic acids   DNA, RNA
AP Biology
RuBisCo
 Enzyme which fixes carbon from air
ribulose bisphosphate carboxylase
 the most important enzyme in the world!

 it makes life out of air!

definitely the most abundant enzyme
I’m green
with envy!
AP Biology
It’s not easy
being green!
Accounting
 The accounting is complicated

3 turns of Calvin cycle = 1 G3P

3 CO2  1 G3P (3C)

6 turns of Calvin cycle = 1 C6H12O6 (6C)

6 CO2  1 C6H12O6 (6C)

18 ATP + 12 NADPH  1 C6H12O6

AP Biology
any ATP left over from light reactions
will be used elsewhere by the cell
Photosynthesis summary
 Light reactions
produced ATP
 produced NADPH
 consumed H2O
 produced O2 as byproduct

 Calvin cycle
consumed CO2
 produced G3P (sugar)
 regenerated ADP
 regenerated NADP

AP Biology
ADP
NADP
Light Reactions
light  ATP + NADPH + O
2
energy
H 2O +
H2O
sunlight
Energy Building
Reactions
NADPH
ATP
AP Biology
O2
 produces ATP
 produces NADPH
 releases O2 as a
waste product
Calvin Cycle
CO2 + ATP + NADPH  C6H12O6 + ADP + NADP
CO2
ADP
NADP
Sugar
Building
Reactions
NADPH
ATP
AP Biology
sugars
 builds sugars
 uses ATP &
NADPH
 recycles ADP
& NADP
 back to make
more ATP &
NADPH
Putting it all together
light
CO2 + H2O + energy  C6H12O6 + O2
H2O
CO2
sunlight
ADP
Energy NADP
Building
Reactions
Sugar
Building
Reactions
NADPH
ATP
AP Biology
O2
sugars
Plants make both:
 energy
 ATP & NADPH
 sugars
even though
this equation
is a bit of a lie…
it makes a
better story
Energy cycle
sun
Photosynthesis
light
CO2 + H2O + energy  C6H12O6 + O2
plants
CO2
glucose
H2O
animals, plants
ATP
C6H12O6 + O2  energy + CO2 + H2O
Cellular Respiration
AP Biology
The Great Circle
of Life,Mufasa!
ATP
O2
Summary of photosynthesis
6CO2 + 6H2O + light  C6H12O6 + 6O2
energy










Where did the CO2 come from?
Where did the CO2 go?
Where did the H2O come from?
Where did the H2O go?
Where did the energy come from?
What’s the energy used for?
What will the C6H12O6 be used for?
Where did the O2 come from?
Where will the O2 go?
What else is involved…not listed in this equation?
AP Biology
Supporting a biosphere
 On global scale,
photosynthesis is the
most important process
for the continuation of life on Earth

each year photosynthesis…
 captures 121 billion tons of CO2
 synthesizes 160 billion tons of carbohydrate

AP Biology
heterotrophs are dependent on plants as
food source for fuel & raw materials
The poetic perspective…
 All the solid material of every plant
was built by sunlight out of thin air
 All the solid material of every animal
was built from plant material
air
AP Biology
sun
Then all the plants, cats,
dogs, elephants & people …
are really particles of air woven
together by strands of sunlight!
If plants can do it…
You can learn it!
Ask Questions!!
AP Biology
2007-2008
Plant pigment lab
AP Biology