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. Makes their own food Use the energy of the sun Ex. Plants. Obtains energy from the foods they consume. Autotrophs vs. Heterotrophs. ATP. Adenosine TriPhosphate Made up of: Adenine - PowerPoint PPT PresentationTRANSCRIPT
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
ATPAdenosine TriPhosphateMade up of:
Adenine5 Carbon sugar (ribose)Three phosphate groups
KEY TO STORE & RELEASE ENERGY
Storing Energy
ADP (Adenosine DiPhosphate)Similar to ATP2 phosphate groupsKey to the way in which living
things store energyAdd on available energy with a
phosphate to ADP to create ATPAnalogy --> 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
P P
Adenine
Ribose
Phosphate
ADP
P P
Adenine
Ribose
Phosphate
ATP
P
8.2 Photosynthesis: An Overview
Photosynthesis
key cellular process identified with energy production
Who goes through photosynthesis?PLANTS
Key PlayersvanHelmont
Most of the gain in mass comes from water
Priestley plant releases oxygen
IngenhouszPlant releases oxygen only
with the presence of light
Photosynthesis Equation
6CO2 6H2O+Carbon dioxide Water
REACTANTS
LIGHT
Photosynthesis Equation
C6H12O6 6O2+Sugar Oxygen
PRODUCTS
LIGHT
Photosynthesis Equation
6CO2 6H2O+ C6H12O6 6O2+LIGHT
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 needLight
Form of energyPigment
light absorbing moleculeChlorophyl
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 processLight dependent
In the thylakoid membranesLight independent (Calvin cycle)
In the stromaRegion 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 moleculesNicotinamide adenine dinucleotide
phosphateAccepts and holds 2 high-energy
electrons along with H+ (hydrogen ions)
This creates NADPHNADP+ + 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
NADP+
2 high energy e-
H+
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
o Light breaks up H2O to
have electrons, H+, and O
o O2 is released into the air
o H+ released into thylakoid membrane
1. Photosystem II
Light Dependent Reaction
e- absorb light
Creates high-energy electrons
2e- passed through e- transport chain
1. Photosystem II
Light Dependent Reaction
2 high energy electrons provide Energy to move H+ from stroma INTO thylakoid membrane
2. Electron Transport Chain
Light Dependent Reaction
o Light re-energizes electrons
o NADP+ picks up high energy electrons and H+
o H+ + NADP+ --> NADPH (electron carriers)
3. Photosystem I
Light Dependent Reaction
o More H+ are pumped across the membrane
o Inside = positive ionso Outside = more negativeo Importance = provides
energy to make ATP
4. Hydrogen Ion Movement
Light Dependent Reaction
a)ATP Synthase = protein on cell membrane• Allows H+ to pass
through membrane
b)ATP Synthase binds ADP + P+, creating ATP
5. ATP Formation
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
1. 6 CO2 enter the cycle from
atmosphere
2. Combine with six 5-Carbon Molecules
3. Result = twelve 3-Carbon Molecules
A. CO2 Enters the Cycle
Calvin Cycle
1. ATP and electrons from NADPH used
2. 12 3-carbon molecules converted to higher energy forms
B. Energy Input
Calvin Cycle
1. Two 3-Carbon molecules are removed• produce sugars, lipids,
amino acids, and other compounds for metabolism
C. 6-Carbon Sugar Produced
Calvin Cycle
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
D. 5-Carbon Molecules Regenerated
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 photosynthesisUntil maximum levels are hit