Chapter 8 Photosynthesis
8.1 Energy and Life
10/27/2005
What is Energy?
Ability to do work
Autotrophs vs. Heterotrophs
Makes their own
food
Use the energy
of the sun
Ex. Plants
Obtains energy
from the foods
they consume
ATP
Adenosine TriPhosphate
Made up of:
Adenine
5 Carbon sugar (ribose)
Three phosphate groups
KEY TO STORE &
RELEASE ENERGY
Storing Energy
ADP (Adenosine DiPhosphate)
Similar to ATP
2 phosphate groups
Key to the way in which living
things store energy
Add on available energy with a
phosphate to ADP to create ATP
Analogy --> Battery
Releasing Energy
How is the energy stored in ATP
released?
Breaking the chemical bond
between the second and third
phosphate group
 Basic energy source of all cells
What is energy used for?
Carry out active transport
 protein synthesis
Responses to chemical
signals
ATP
 can only pack small
amounts of energy
Adenine
Phosphate
P
P
Ribose
ADP
Adenine
Phosphate
P
P
Ribose
ATP
P
8.2 Photosynthesis: An Overview
Photosynthesis
 key cellular process
identified with energy
production
 Who goes through
photosynthesis?
PLANTS
Photosynthesis Equation
REACTANTS
LIGHT
6CO2 + 6H2O
Carbon dioxide
Water
Photosynthesis Equation
PRODUCTS
LIGHT
Sugar
Oxygen
C6H12O6 + 6O2
Photosynthesis Equation
6CO2 + 6H2O
LIGHT
C6H12O6 + 6O2
DESCRIBE WHAT IS HAPPENING IN THE REACTION.
In photosynthesis, plants use the energy
of sunlight to change water and carbon
dioxide into high-energy sugars and
oxygen.
Lights and Pigments
Plants need
Light
Form of energy
Pigment
 light absorbing molecule
Chlorophyl
Principal pigment in plants
8.3 The Reactions of Photosynthesis
Chloroplast
 where
photosynthesis
takes place
 thylakoid
membranes =
saclike
photosynthetic
materials found in
chloroplast
Chloroplast
 Granum = stack
of thylakoid
 photosystems =
organization of
chlorophyll and
other pigments
 light collecting
units of the
chloroplast
Photosystems
2 part process
Light dependent
In the thylakoid membranes
Light independent (Calvin cycle)
In the stroma
Region outside the
thylakoid membranes
Electron Carriers
 Sunlight excites electrons in
chlorophyll
 electrons gain tons of energy
 high energy electrons need special
carriers from chlorophyll to other
molecules
Light Dependent
Reactions
 requires lights
 uses energy from
light to produce
ATP and NADPH
Light Dependent
Reactions
 Products
 OXYGEN GAS (02)
 2 energy carriers
 ADP -- > ATP
 NADP+ --> NADPH
Light Dependent Reaction
5. ATP Formation
a)ATP Synthase = protein
on cell membrane
• Allows H+ to pass
through membrane
b)ATP Synthase binds ADP
+ P+, creating ATP
Light Dependent
Reactions
 Products
 OXYGEN GAS (02)
 2 energy carriers
 ADP -- > ATP
 NADP+ --> NADPH