Photosynthesis is the process by which plants, algae, and some bacteria use sunlight, water and carbon dioxide to produce oxygen and energy in the form of glucose. It occurs in two stages - the light-dependent reactions where light energy is captured and used to produce ATP and NADPH, and the light-independent Calvin cycle where ATP and NADPH fuel the building of glucose molecules from carbon dioxide. Chlorophyll and other pigments absorb sunlight which is then used to split water, producing oxygen, protons and electrons. The electrons are passed through an electron transport chain which generates a proton gradient used for ATP synthesis.

1. CHAPTER 8:
PHOTOSYNTHESIS

2. 8-1 Energy of Life
Energy=
Living organisms depend on energy.
Living things get energy from _______.
The ultimate source of energy is the _____.
The ability to do work
food
sun

3. A. Autotrophs and Heterotrophs
 Autotrophs=
o Example: plants use sunlight to make food
 Heterotrophs=
o Example: ___________- eat plants
___________- eat animals that
have stored energy from
plants they eat
___________- eat decomposing
organisms
Organisms that make their own food
Organisms that need to consume
food for energy
herbivores
carnivores
detritovores

4. Adenine Ribose 3 Phosphate groups
Section 8-1
ATP
B. Chemical Energy and ATP
•Forms of energy: light, heat, electricity, and
•_____ (Adenosine Triphosphate)=
Chemical energy (stored in bonds)
ATP
The basic energy source (chemical energy) of all cells

5. 1. Storing Energy
• ADP (Adenosine Diphospate) contains ____ phosphates
instead of 3.
• If a cell has extra energy,
2. Releasing Energy
• To release energy stored in ATP,
2
Small amounts can be stored by adding a
phosphate group to ADP molecules to produce ATP.
The cell can break the high energy bond between
the 2nd and 3rd phosphate group

6. ADP ATP
Energy
Energy
Adenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP)
Partially
charged
battery
Fully
charged
battery
Section 8-1
Figure 8-3 Comparison of ADP and
ATP to a Battery

7. C. Using Biochemical Energy
 How ATP is used in the cell
-
- aids in
-
-
 Cells contain a small amount of ATP.
Only enough to provide a few seconds of activity.
 ATP is great at ________________ but not good at
 Glucose stores ___ times more energy than ATP.
 The energy stored in Glucose can be used to
Carry out active transport
moving organelles throughout the cell
Protein synthesis
Producing light (ex. fireflys)
transferring energy
Storing large amounts of energy
90
regenerate ATP when the cell needs it.

8. 8-2 Photosynthesis: An Overview
Photosynthesis=
 Plants convert ______________ into ______________
through a series of oxidation/reduction reactions.

Process where plants use energy of sunlight
to convert water and carbon dioxide into
high-energy Carbohydrates-sugars-starches-
and oxygen, a waste product.
Sunlight energy Chemical energy
6 CO2 + 6H2O + SUNLIGHT → C6H12O6 (SUGAR) + 6O2

9. 6 CO2 + 6H2O + SUNLIGHT → C6H12O6 (SUGAR) + 6O2
sunlight
O2
CO2
H2O
C6H12O6

10. Reduction:
Gain electrons
Oxidation:
Lose electrons
REDOX REACTIONS
LEO: Lose Electrons Oxidation
goes
GER: Gain Electrons Reduction

11. Light Energy
Chloroplast
(Chlorophyll)
CO2 + H2O
Sugars + O2
Section 8-2
Photosynthesis: Reactants and Products

12. A. Investigating Photosynthesis
 Investigations into photosynthesis began with the
following question:
“When a tiny seedling grows into
a tall tree with a mass of several tons,
where does the tree’s increase in mass come from?”

13. 1. ______________ Experiment (1643)
 Put soil in pot and took mass
 Took a seedling and took mass
 Put seed in soil...watered...waited five years...
the seedling became a tree.
 He concluded that
 He determined the
Van Helmont’s
the mass came from water
“hydrate” in the carbohydrate
portion of photosynthesis

14. Von Helmont Willow Tree
Experimenthttp://www.teachersdomain.org/resource/tdc02.sci.life.stru.photosynth/
2.3 kg. (5 lb.) plant
90.8 kg (200 lbs). soil
76.8 kg (169 lbs. 3 oz.)
Soil 57 g less
5 years

15. 2. ___________ Experiment (1771)
 Put a lit candle in a bell jar-
 Placed a mint plant in the jar with the candle-
 Concluded
 He determined
Priestly’s
The flame died out.
Flame lasted longer
plants release a substance needed
for candle burning.
plants release oxygen

16. Alternate Priestly Experiment
•Credit: The National Science Teachers Association

17. 3. ________________Experiment (1779)
 Put aquatic plants in light...
 Put aquatic plants in dark...
 He determined:
4. _______________ (1948)
 He determines
 Known as the
Jan Ingenhousz
produced oxygen
No oxygen
Light is needed to produce oxygen
Melvin Calvin
carbon’s path to make glucose
Calvin’s cycle

19. B. Light and Pigments
 Photosynthesis requires ______ (soil), ____________ (air),
and ____ (sun), and ________ (a molecule in chloroplasts).
 Energy from the sun is in the form of _____.
 Sunlight= perceived as white light=
 The wavelengths you can see are part of the
_______________.
 Plants capture light with light absorbing molecules called
________.
 The main pigment is chlorophyll (2 kinds)
1.
2.
water Carbon dioxide
light chlorophyll
light
A mixture of different
wavelengths
Visible Spectrum
pigments
Chlorophyll a
Chlorophyll b

20. Absorption of Light by
Chlorophyll a and Chlorophyll b
V B G YO R
Chlorophyll b
Chlorophyll a
Section
8-2
Figure 8-5 Chlorophyll Light
Absorption
 Chlorophyll absorbs light in the __________ and
___ wavelengths
Gamma
rays
X-rays UV Infrared Micro-
waves
Radio
waves
Visible light
Wavelength (nm)
Blue-violet
red
RED
ORANGE
YELLOW
GREEN
BLUE
INDIGO
VIOLET

21.  Chlorophyll reflects ______ wavelengths (that’s why
plants appear green)
 The energy absorbed by chlorophyll is transferred to
_________ (in chloroplasts) which makes
photosynthesis work.
green
electrons
QUESTION: So why do plants leaves
change color in the fall?
Colorful leaves signal the changes of
autumn. As nights grow longer and
cooler, the leaves no longer produce
chlorophyll, the pigment that makes
leaves green and enables the
process of photosynthesis. As the
green pigment wanes, other
pigments take over, producing the
brilliant reds, oranges, and yellows of
fall foliage.

22. • The location and structure of chloroplasts
Figure 7.2
LEAF CROSS SECTION MESOPHYLL CELL
LEAF
Chloroplast
Mesophyll
CHLOROPLAST Intermembrane space
Outer
membrane
Inner
membrane
Thylakoid
compartmentThylakoidStroma
Granum
StromaGrana

23. 8.3 INFORMATION
Overview of Photosynthesis Light and Dark Reactions

24. Light
Chloroplast
Reflected
light
Absorbed
light
Transmitted
light
8-3 The Reactions of Photosynthesis
A. Inside a Chloroplast
•Site of Photosynthesis= The chloroplasts

25.  Photosynthesis is a two part process:
1.
-aka:
2.
-aka:
-aka:
-aka:
Chloroplast
Light
O2
Sugars
CO2
Light-
Dependent
Reactions
Calvin
Cycle
NADPH
ATP
ADP + P
NADP+Chloroplast
Section 8-3
Figure 8-7 Photosynthesis: An Overview
Light-dependent reactions (located in thylakoid membranes)
Light Reaction
Light-independent reactions (located in stroma)
Dark reaction
Calvin Cycle
Carbon fixation
H20

26. • An overview of photosynthesis
Figure 7.5
Light
Chloroplast
LIGHT
REACTIONS
(in grana)
CALVIN
CYCLE
(in stroma)
H2O
O2
CO2
NADP+
ADP
+ P
Sugar
ATP
NADPH

27. B. Electron Carriers
 Sunlight energy is transferred to
 The electrons
 High energy electrons require
ANALOGY: If you wanted to transfer hot coals from one campfire to another, it requires
a special carrier like a pan or bucket.
 Electron carriers pass electrons from carrier to carrier
to carrier;
 A Key electron carrier in photosynthesis is NADP+.
NADP+ + + →→
(electron carrier) (high energy electrons) (hydrogen ions) (energy storing compound)
 When energy is needed to do cellular work, the
electrons in chlorophyll.
gain a lot of energy.
a special carrier
(molecule/compound).
Forming an electron transport chain.
2e- H+ NADPH
Covalent bonds of NADPH are broken to release
the high energy electrons.

28. C. Light-Dependent Reactions (Requires Light)
· Located in the ___________________________
· In the light reaction, ___________ is used to produce
_____ and _______
http://www.fw.vt.edu/dendro/forestbiology/photosynthesis.swf
thylakoid membrane
light energy
ATP NADPH

29. PSII PS
I
2H2O
O2 + 4H+
Electron
Transport Chain
NADP+ NADPH
Electron
Transport Chain
ADP ATP
e~
4e~
e~
e~
e~
e~
e~
Overview of the Light Reaction
http://www2.kumc.edu/netlearning/examples/flash/photosyn2.html

30. Primary
electron acceptor
Primary
electron acceptor
Photons
PHOTOSYSTEM I
PHOTOSYSTEM II
Energy for
synthesis of
by chemiosmosis
http://www2.kumc.edu/netlearning/examples/flash/photosyn2.html

31. KEY PLAYERS IN LIGHT REACTION:
 Photosystem I and II:
 Electron carriers:
 Water:
• ATP Synthase:
Clusters of chlorophyll pigment
ADP and NADP+
Donates electrons
Enzyme (protein) that makes ATP

32. Figure 7.7C
Primary
electron acceptor
Photon
Reaction center
PHOTOSYSTEM
Pigment
molecules
of antenna

33. Hydrogen
Ion Movement
Photosystem II
Inner
Thylakoid
Space
Thylakoid
Membrane
Stroma
ATP synthase
Electron
Transport Chain Photosystem I ATP Formation
Chloroplast
Light Reaction Process:

34. LIGHT REACTIONS
8.3

35. • The production of ATP by chemiosmosis in
photosynthesis
Figure 7.9
Thylakoid
compartment
(high H+)
Thylakoid
membrane
Stroma
(low H+)
Light
Antenna
molecules
Light
ELECTRON TRANSPORT
CHAIN
PHOTOSYSTEM II PHOTOSYSTEM I ATP SYNTHASE

36. A. Photosystem II (PSII)
* Absorbs light to
2H2O
o e- =
o O2 =
o H+=
B. Electron Transport Chain
* The light energy
* The electrons get passed
split (break up) water molecules
→ 4H+ + 4e- + O2
Donated to chlorophyll
Released into air providing oxygen for us
Released inside the thylakoid membrane
excites electrons increasing
their energy level.
down an electron transport chain to
photosystem I (PSI)

37. C. Photosystem I
· Light energy energizes electrons.
· NADP+ accepts the electrons and an H+ and are
used to make _________.
D. Hydrogen Ion Movement
· When water splits,
· The difference in charges
http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120068/bio05.swf::Proton%20Pump
E. ATP Formation
· _____ do not cross the membrane directly.
It needs the help of a membrane protein.
· H+ ions pass through the protein:
NADPH
H+ ions fill up the inner thylakoid membrane
(making it positively charged). As a result, the
stroma is negatively charged.
Provides the energy to make ATP.
Ions
ATP synthase is an enzyme that converts ADP to ATP

38. PRODUCTS OF THE LIGHT REACTION:
· ____ : Released in the air
· ______________: These contain abundant chemical
energy but they are unstable. So, they are used to power
the dark reaction to _________________ which
can store the energy for longer periods of time.
O2
ATP & NADPH
help build glucose

39. DARK REACTIONS
8.3

40. ChloropIast
CO2 Enters the Cycle
Energy Input
5-Carbon
Molecules
Regenerated
Sugars and other compounds
6-Carbon Sugar
Produced
8-3 D. The Calvin Cycle (dark reaction; light independent)
* Occurs in the
http://faculty.nl.edu/jste/calvin_cycle.htm
Figure 8-11 Calvin Cycle
Stroma with or without light.

41. The Calvin Cycle
(CO2)
(Unstable intermediate)
ATP
ADP +
ADP +
(Sugars and other carbohydrates)
NADPH
NADP+
(PGAL)
(PGAL)
ATP
(PGAL)
(RuPB)

42. DARK REACTION PROCESS:
A. CO2 enters the system
•
• product=
B. Energy input
• The _________________________________ are used to
C. 6-Carbon Sugar is produced
• ___ of the 12 3-C are used to make glucose and
other compounds.
D. 5-Carbon Molecules Regenerated
• ___ remaining 3-C are converted into 6 5-C molecules
6 CO2 combines with 6 5-C compounds
12 3-C compounds
ATP & NADPH (from the light reaction)
convert the 12 3-C compounds into a higher energy form.
2
10

43. PRODUCTS OF THE CALVIN CYCLE (DARK REACTION):
*
E. Factors Affecting Photosynthesis
*
* Plants often have a ______ coating to protect against
*
* The greater the _____________, the better
photosynthesis functions (up to a point).
High Energy Sugars
Shortage of water can stop/slow down photosynthesis
waxy
Very low/high temperatures (damages enzymes) can
stop/slow down photosynthesis (optimal temp.= 0°– 35° C
Light intensity

44. Photosynthesis
includes
of
take place in
takes place in uses
to produce to produce
use
Light-
dependent
reactions
Calvin cycle
Thylakoid
membranes Stroma NADPHATPEnergy from
sunlight
ATP NADPH O2 Chloroplasts High-energy
sugars
Section 8-3
Concept Map