Photosynthesis
Plant – multicellular eukaryotes that have
cell walls made of cellulose and
photosynthesize.
Billy
“stationary animals that eat sunlight”
Adenosine Triphosphate (ATP)
One of the most important compounds that cells use.
Stores and releases energy - adenosine triphosphate
(ATP).
 ATP consists of adenine, a 5-carbon sugar called
ribose, and three phosphate groups.

Adenosine Triphosphate (ATP)
Adenosine diphosphate
(ADP) has two phosphate
groups instead of three. ADP
does not contain as much
energy as ATP. Another P is
added to ADP to form ATP.
 Cells release the energy stored
in ATP by breaking the bonds
between the second and third
phosphate groups.

Uses of ATP
Powers protein pumps in the
cell membrane
 Powers cilia and flagella
 Power for synthesis of
proteins
 Powers motor proteins that
contract muscles
 Provides cell energy

How could a small seed become a giant tree?
Heterotroph – obtains energy
from food it consumes
Autotroph – uses energy
from the sun to produce food
Photosynthesis - autotrophs use
the energy of sunlight to
produce high-energy
carbohydrates that can be used
for food.
Autotroph or Heterotroph
Photosynthesis
6CO2 + 6H2O
Carbon
Dioxide
LIGHT
C6H12O6 + 6O2
Glucose
Water
Oxygen
What is Light?
Light Speed, c = 2.9979 x 108 m/s
Or 670.6 million mph
Which type of light
carries more energy, blue
or red?
Electromagnetic Spectrum
Wave length and energy are
inversely proportional
• The smaller the wave length, the
more energy
• Blue light is high energy
• Red light is low energy
Why are plants usually green?
They reflect green light
Plant Pigments


Pigments – light absorbing molecules
Chlorophyll – the most abundant pigment
in plants, that absorbs blue and red light.


Chlorophyll a - a blue-green pigment
Chlorophyll b - a yellow-green pigment
Accessory Pigments

Carotene - an orange pigment

Xanthophyll - a yellow pigment

Anthocyanin – a red pigment
Photosynthesis

Takes place in the
chloroplast



Thylakoids – saclike
photosynthetic
membrane in the
chloroplast
Grana – stacks of
thylakoids
Stroma - the region
outside of the thylakoid
membranes
Photosynthesis (Overall)
H2O
CO2
Chloroplast
Light
NADP+
ADP
Light
+
Dark
P
CALVIN
CYCLE
(in stroma)
LIGHT
REACTIONS
(in thylakoids)
ATP
NADPH
O
Sugar
Factors Affecting Photosynthesis

Shortage of water


Temperature


H2O acts as the electron
donor in the light
dependent reaction
Photosynthesis is
controlled by enzymes
that work best between 0
C and 35 C.
Light Intensity

More light increases rate
of photosynthesis


Photosynthesis and respiration are
complimentary processes.
Products of one are reactants for the other.
Photosynthesis
Light
energy
6 CO2
+
6
Carbon dioxide
H2O
Water
C6H12O6
+
Glucose
PHOTOSYNTHESIS
6
O2
Oxygen gas
Respiration
C6H12O6
Glucose
+
6
O2
Oxygen gas
6
CO2
Carbon
dioxide
+
6
H2O
Water
+
ATPs
Energy
Organize your thoughts
Working in pairs at your tables please address the
following:

What is the chemical equation for photosynthesis
(reactants/products)

What is light? How does it play a role in
photosynthesis?

Write down everything that you already know
about photosynthesis.

Lastly, what is it that you don’t understand about
plants or photosynthesis?
Green Solar Cells
1.
2.
3.
4.
5.
What is responsible for the various shades of
green in plants?
What is the function of the stroma lamellae?
What evidence supports the theory that
chloroplast were once invasive cells?
How is excess food stored?
How does the author define photosynthesis?
5
6
2
4
1
3
Photosynthesis – Light and Dark Reactions
1 H2O
3CO2
Chloroplast
Light
NADP+
ADP
+
P
Light
CALVIN
CYCLE
(in stroma)
LIGHT
REACTIONS
(in thylakoids)
ATP
NADPH
2
O
4
Sugar
Dark
Dark Reaction (Calvin Cycle)
1._______
3.___________
2._______________
4._____________
5._____________
6._______
7._______
Homework (for Thurs. 12/9):
1. In text read pgs 230-233
2. In 8.2 assessment on pg 234
answer question #1,2 and 3 all
parts of each question
Using the light reaction diagram:
On your own, describe the four
steps of the light reaction in your
own words. Use complete
sentences.
In your group:
1.
2.
3.
4.
5.
See if you can write the chemical
equation for photosynthesis (inputs and
outputs)
What is the organelle in plant cells that is
most involved with photosynthesis
Explain why this organelle captures
energy
What is light?
Make a list of things you already know
about photosynthesis
Light Reaction
8.
H+ Concentration =
10.
4.
7.
9.
Type of transport =
5.
Type of Transport =
1.
2.
3.
6.
H+ Concentration =