Energy Carriers

In Photosynthesis, energy in sunlight is used to make food. In Photosynthesis, energy in sunlight is used to make food. In Respiration, food is broken down to release energy. In Respiration, food is broken down to release energy. Molecules ADP, NAD + and NADP + trap and transfer this energy Molecules ADP, NAD + and NADP + trap and transfer this energy

ADP ADP = Adenosine DiPhosphate ADP = Adenosine DiPhosphate This molecule is found in ALL living cells. This molecule is found in ALL living cells. Adenine—Ribose—Phosphate ~ Phosphate Adenine—Ribose—Phosphate ~ Phosphate Unstable bond ADP is a low energy molecule ADP is a low energy molecule

ATP ATP = Adenosine TriPhosphate ATP = Adenosine TriPhosphate Add another phosphate to ADP = ATP Add another phosphate to ADP = ATP Adenine —Ribose—Phosphate~Phosphate~Phosphate Extra energy in unstable bond Extra energy in unstable bond Phosphorylation=adding a phosphate group Phosphorylation=adding a phosphate group ADP + energy + P  ATP + Water ADP + energy + P  ATP + Water ATP is an Energy rich compound ATP is an Energy rich compound

ATP ATP stores energy, not for long though ATP stores energy, not for long though It can be moved around inside a cell It can be moved around inside a cell When ATP breaks down to ADP it releases energy When ATP breaks down to ADP it releases energy Energy released is used to carry out most reactions in the cells. Energy released is used to carry out most reactions in the cells. ATP + Water  ADP + P + energy ATP + Water  ADP + P + energy Cells release energy from ATP 10 million times per second Cells release energy from ATP 10 million times per second

ATP and ADP

NADP + NADP + = Nicotinamide Adenine Dinucleotide Phosphate NADP + = Nicotinamide Adenine Dinucleotide Phosphate Is a low energy molecule involved in Photosynthesis Is a low energy molecule involved in Photosynthesis NADP + accepts a Hydrogen proton+ 2 electrons = NADPH NADP + accepts a Hydrogen proton+ 2 electrons = NADPH NADP electrons + H +  NADPH NADP electrons + H +  NADPH (Low energy) (High energy) (High energy) The Addition of Electrons to a molecule = Reduction The Addition of Electrons to a molecule = Reduction NADP + is said to be reduced to NADPH NADP + is said to be reduced to NADPH

NADPH NADPH is a very High energy molecule. NADPH is a very High energy molecule. It is an electron carrier It is an electron carrier Energy it carries is used in photosynthesis Energy it carries is used in photosynthesis When it breaks down it releases 2 high-energy electrons & a hydrogen ion When it breaks down it releases 2 high-energy electrons & a hydrogen ion  NADPH  NADP electrons + H + (High Energy) (Low Energy) (High Energy) (High Energy) (Low Energy) (High Energy)

ATP Vs NADPH

NADP + Vs NAD + NAD + = Respiration NAD + = Respiration NADP + = Photosynthesis NADP + = Photosynthesis NAD + is a low energy molecule just like NADP + and changes to the high-energy molecule NADH just like NADPH NAD + is a low energy molecule just like NADP + and changes to the high-energy molecule NADH just like NADPH

Photosynthesis Plants making their own food

Role of Photosynthesis Plants use it to make food Plants use it to make food Animals get their food from plants Animals get their food from plants It produces oxygen which is needed to release energy in respiration It produces oxygen which is needed to release energy in respiration It is responsible for forming fossil fuels It is responsible for forming fossil fuels It removes carbon dioxide from the air It removes carbon dioxide from the air

Photosynthesis requires: carbon dioxide, carbon dioxide, water, water, light energy, light energy, chlorophyll. chlorophyll.

Photosynthesis produces glucose glucose waste oxygen waste oxygen

Photosynthesis converts light energy light energy chemical energy chemical energy

Stages in Photosynthesis Light is absorbed Light is absorbed - By Chlorophyll in Chloroplast Water is split Water is split - 2H 2 O  4H + +4e - + O 2 Products are produced Products are produced - Oxygen, hydrogen ion & electrons Light energises electrons Light energises electrons -sunlight energises electrons through chlorophyll Glucose is formed Glucose is formed - CO 2 + H + + E -  C 6 H 12 O 6

Sources of Light CO 2 & H 2 O Light Sun Sun Artificial bulbs Artificial bulbs Carbon Dioxide Animals respiring Animals respiring Burning of fossil fuels Burning of fossil fuelsWater In soil due to rain or nearby rivers & lakes In soil due to rain or nearby rivers & lakes

2 stages of Photosynthesis Photosynthesis Light StageDark Stage

Light Stage Light Stage This takes place in the grana of the chloroplast This takes place in the grana of the chloroplast It makes energy for converting ADP + P into ATP It makes energy for converting ADP + P into ATP It makes hydrogen ions from the splitting of water to use in the dark stage of photosynthesis It makes hydrogen ions from the splitting of water to use in the dark stage of photosynthesis

Light stage Light Stage Phosphorylation Making ATP Photolysis Splitting water

Photolysis The splitting of water Water 2H20 Hydrogen ions 4H + Used to convert NADP To NADPH Electrons 4E - Go back to chlorophyll Oxygen 02 By product Excreted through leaf

Water Splitting Equation 2H 2 O  4H + +4e - + O 2 Light

Phosphorylation Making ATP and NADPH Where do plants get their energy from? Where do plants get their energy from? - Sun Light There are 7 different colours in white light, the plant can only absorb these if it has a pigment. There are 7 different colours in white light, the plant can only absorb these if it has a pigment. The most important pigment is Chlorophyll because it sits next to an electron acceptor. The most important pigment is Chlorophyll because it sits next to an electron acceptor. The electron acceptor takes the energy from the pigments and adds it into electrons. The electron acceptor takes the energy from the pigments and adds it into electrons.

Chloroplast Pigments – In Grana Light energy absorbed Pigments Energy Passed on Energised electrons passed on Electron acceptor

Electron Flow Pathways to make ATP & NADPH 2 Different Pathways 1. Cyclic PhotoPhosphorylation ( circle) (light) (adding a phosphate) 2. Non-Cyclic PhotoPhosporylation

Electron Pathway 1: Cyclic Photophosporylation Light energy absorbed ADP + P ATP + Water Electron flow that looses energy as it goes around ADP traps this energy by adding another phosphate Electron Acceptors E-E- E-E- E-E- E-E- E-E- Chlorophyll Energy

Electron Pathway 1: Cyclic PhotoPhosphorylation High energy electrons travel around a series of electron acceptors & back again to chlorophyll High energy electrons travel around a series of electron acceptors & back again to chlorophyll As they move around they loose energy As they move around they loose energy This energy is trapped by ADP and a phosphate within their bonds. This energy is trapped by ADP and a phosphate within their bonds. This forms ATP and water. This forms ATP and water. ADP + energy + Phosphate  ATP + water ADP + energy + Phosphate  ATP + water

Electron Pathway 2: Non -Cyclic Photophosporylation Light energy absorbed 2H 2 O ATP + Water Electron Acceptors 2E - O2O2 4H + 4E - ADP + P 2E - NADP + NADP - NADPH Chlorophyll 2E - Light + H +

Electron Pathway 2: Non-Cyclic PhotoPhosphorylation 2 high energy electrons passed along at a time through a series of electron acceptors 2 high energy electrons passed along at a time through a series of electron acceptors They loose energy as they pass from acceptor to acceptor, this energy is used to make ATP They loose energy as they pass from acceptor to acceptor, this energy is used to make ATP At the end 2 electrons combine with NADP + to form NADP -. At the end 2 electrons combine with NADP + to form NADP -. Water is split using light energy, 2 electrons return to chlorophyll while the protons attach to NADP - to form NADPH Water is split using light energy, 2 electrons return to chlorophyll while the protons attach to NADP - to form NADPH

Products of Light Stage Oxygen Oxygen ATP ATP NADPH NADPH

Dark Stage This is also known as the Calvin cycle This is also known as the Calvin cycle It takes place in the stroma of the chloroplast It takes place in the stroma of the chloroplast It uses energy got from breaking down It uses energy got from breaking down ATP into ADP + P It uses hydrogen ions and electrons got from breaking down It uses hydrogen ions and electrons got from breaking down NADPH into NADP electrons + H +

Dark Stage Calvin Cycle 6CO2 Oxygen atoms are removed 12 Hydrogen ions are added Glucose is formed C6H120 6 Electrons are added

Dark Stage Calvin Cycle Carbon DioxideGlucose (C 6 H 12 O 6 ) NADP + NADPH ATPADP + P

Main events in photosynthesis Light energy is absorbed by chlorophyll Light energy is absorbed by chlorophyll Water is split Water is split The electrons are passed to chlorophyll The electrons are passed to chlorophyll The protons are stored in the chloroplasts The protons are stored in the chloroplasts The oxygen is released The oxygen is released Sunlight transfers energy to electrons Sunlight transfers energy to electrons The high energy electrons, stored protons( the hydrogen ions) and carbon dioxide are used to make glucose The high energy electrons, stored protons( the hydrogen ions) and carbon dioxide are used to make glucose

Light Chlorophyll Electron Deficient Chlorophyll High Energy Electrons Water Protons + electrons + oxygen Proton Pool ADP ATP NADP + NADPH Released