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 P Ribose ATP
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 6CO 2 + 6H 2 O LIGHT Carbon dioxide Water
Photosynthesis Equation PRODUCTS LIGHT Sugar Oxygen C H O + 6O 6 12 6 2
Photosynthesis Equation 6CO 2 LIGHT + 6H 2 O C 6 H 12 O 6 + 6O 2 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 e- H + 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 (0 2 ) 2 energy carriers ADP -- > ATP NADP+ --> NADPH
Light Dependent Reaction 1. Photosystem II o Light breaks up H 2 O to have electrons, H+, and O o O 2 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 e- transport 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 (0 2 ) 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. CO 2 Enters the Cycle 1. 6 CO 2 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 CO 2 molecules to begin the next cycle
Calvin Cycle It takes 6CO 2 to produce a SINGLE 6-Carbon sugar molecule Removes CO 2 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