PowerPoint Presentation - Chapter 8 Photosynthesis

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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
Key Players
vanHelmont
Most of the gain in mass
comes from water
Priestley
 plant releases oxygen
Ingenhousz
Plant releases oxygen only
with the presence of light
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
Electron Transport Chain
carrier molecule = compound that
can accept a PAIR of high-energy
electrons and transfer them to
along with MOST of their energy
NADP+
One of the carrier molecules
Nicotinamide adenine dinucleotide
phosphate
Accepts and holds 2 high-energy
electrons along with H+ (hydrogen
ions)
This creates NADPH
NADP+ + H+ --> NADPH = converts
energy sunglight into chemical form
NADPH
 carries high-energy electrons
produced by light absorption
in chlorophyll to chemical
reactions
 used for synthesis of
molecules
2 high energy eH+
NADP+
NADPH
8.3B
11 / 13 / 06
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
1. Photosystem II
o Light breaks up H2O to
have electrons, H+, and O
o O2 is released into the air
o H+ released into thylakoid
membrane
Light Dependent Reaction
1. Photosystem II
e- absorb light
Creates high-energy electrons
2e- passed through etransport chain
Light Dependent Reaction
2. Electron Transport Chain
2 high energy electrons
provide Energy to move
H+ from stroma INTO
thylakoid membrane
Light Dependent Reaction
3. Photosystem I
o Light re-energizes electrons
o NADP+ picks up high energy
electrons and H+
o H+ + NADP+ --> NADPH
(electron carriers)
Light Dependent Reaction
4. Hydrogen Ion Movement
o More H+ are pumped across
the membrane
o Inside = positive ions
o Outside = more negative
o Importance = provides
energy to make ATP
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
8.3 C
11 / 14 / 06
Quickwrite
1. What
Calvin Cycle
 uses ATP and NADPH
from Light Dependent
Reaction
 Product - High energy
Carbohydrates (sugar,
starch)
Calvin Cycle
A. CO2 Enters the Cycle
1. 6 CO2 enter the cycle from
atmosphere
2. Combine with six 5-Carbon
Molecules
3. Result = twelve 3-Carbon
Molecules
Calvin Cycle
B. Energy Input
1. ATP and electrons from
NADPH used
2. 12 3-carbon molecules
converted to higher energy
forms
Calvin Cycle
C. 6-Carbon Sugar Produced
1. Two 3-Carbon molecules
are removed
• produce sugars, lipids,
amino acids, and other
compounds for
metabolism
Calvin Cycle
D. 5-Carbon Molecules Regenerated
1. ATP is used
2. Ten 3-Carbon molecules
convert back to six 5-Carbon
molecules
3. 5-Carbon molecules combine
with 6 CO2 molecules to begin
the next cycle
Calvin Cycle
 It takes 6CO2 to produce a
SINGLE 6-Carbon sugar
molecule
 Removes CO2 from air
 Sugar needed for growth and
development
Create a Flow Chart
6 ____ go into cycle
Combines with six ________
molecules
Results = _____________
molecules
ATP and Electrons used from
NADPH
____________ molecules
converted into higher
energy forms
Two __________
Molecules removed
Produces
________________________
________________________
_______
______ 3-Carbon molecules
converted back to 6
__________ molecule
Cycle repeats!
Factors Affecting Photosynthesis
 shortage of water = slow
or stop photosynthesis
 temperature = damage or
slow down how enzymes
work
Factors Affecting Photosynthesis
 intensity of light = more
light, increase
photosynthesis
Until maximum levels
are hit