The Need for The Need for Energy: Energy:

Photosynthesis Photosynthesis and Cellular and Cellular RespirationRespiration

Energy in a CellEnergy in a CellThe Need for EnergyThe Need for Energy

All organisms require energy All organisms require energy for:for:

Active transportActive transport Cell divisionCell division MovementMovement Production of proteinsProduction of proteins

Energy in a CellEnergy in a CellEnergy is stored in the Energy is stored in the ATPATP

moleculemolecule ATP: adenosine triphosphateATP: adenosine triphosphate Made up of adenosine + Made up of adenosine + 33

phosphate groupsphosphate groups

Energy in a CellEnergy in a Cell

AdenosinePhosphate

Phosphate

Phosphate

High-energy bond: Stores a lot of energy

*This energy is released when the bond is broken*

ATP

AdenosinePhosphate

Phosphate

Energy

ADP

Energy in a CellEnergy in a Cell ADP: Adenosine diphosphateADP: Adenosine diphosphate

Cells Cells recyclerecycle the ADP to make new the ADP to make new ATPATP to store more energy for future to store more energy for future useuse

Many proteins have spots where ATP Many proteins have spots where ATP attaches to provide attaches to provide energyenergy for the for the protein to do its job, then the ADP is protein to do its job, then the ADP is released for recyclingreleased for recycling

PhotosynthesisPhotosynthesis Process that uses the Process that uses the sun’ssun’s energy to energy to

make make glucoseglucose

Carried out by Carried out by green plantsgreen plants and some and some bacteriabacteria

Purpose is to trap sun’s energy and store Purpose is to trap sun’s energy and store it in glucose (food for the plant)it in glucose (food for the plant)

Photosynthesis occurs in the Photosynthesis occurs in the chloroplastchloroplast

PhotosynthesisPhotosynthesis

Structure of the chloroplast:Structure of the chloroplast:

Granum stack: Stack of green thylakoids

Stroma: Space inside the chloroplast

Thylakoid: Green disk in the chloroplast

PhotosynthesisPhotosynthesis

Thylakoids are green because they Thylakoids are green because they contain contain chlorophyllchlorophyll

Chlorophyll: Chlorophyll: greengreen pigment in plants that pigment in plants that absorbs light energyabsorbs light energy

PigmentPigment: light-absorbing compound: light-absorbing compound

Photosynthesis: The Photosynthesis: The Chemical EquationChemical Equation

6CO2 + 6H2O + light energy 6CO2 + 6H2O + light energy C6H12O6 + 6O2 C6H12O6 + 6O2

carbon dioxide + carbon dioxide + waterwater + sunlight + sunlight glucose + oxygen glucose + oxygen

Photosynthesis: Photosynthesis: The 2 StepsThe 2 Steps

1. Light reaction (Light-dependent reaction)1. Light reaction (Light-dependent reaction)

- - FirstFirst step of photosynthesis that traps step of photosynthesis that traps sunlight and makes electrons and ATP to run sunlight and makes electrons and ATP to run the dark reactionthe dark reaction

2. Dark reaction (Light-independent reaction)2. Dark reaction (Light-independent reaction)

-- SecondSecond step of photosynthesis that uses ATP step of photosynthesis that uses ATP and electrons from the and electrons from the light reactionlight reaction and and carbon dioxide from the air to make carbon dioxide from the air to make glucoseglucose

Photosynthesis Step 1: Light Reaction – occurs in the thylakoids inside the chloroplast

Chlorophyll in the thylakoids

1a

e-

1

b

ATP

e-

e- e-

NADPH

Electron transport chain

Water e- Oxygen

1d

1c

1a. Light energy is absorbed by the chlorophyll

1b. Electrons jump out of the chlorophyll atoms

1c. Electrons move down the electron transport chain (series of proteins that pass the electrons along). Electrons are caught by the NADPH compound. ATP is made.

1d. Photolysis: Water is broken down into oxygen (given off by plant) and electrons (replace lost electrons in chlorophyll). These electrons recharge the system so the light reaction can happen again.

Photosynthesis Step 2: Dark Reaction (Calvin Cycle) – Occurs in the stroma

2a. Electrons and ATP from light reaction get dumped into the Calvin Cycle to run it

2b. Calvin Cycle: Series of steps that build up compounds using carbon dioxide from the air

Calvin Cycle

ATP

Carbon dioxide from the air

PGAL

2 PGAL = 1 glucose

2c. PGAL compound sometimes leaves the cycle. 2 PGAL compounds added together make 1 glucose.

e-

e-

e-

e-

e-

NADPH