Cell EnergyCell Energy

Photosynthesis and RespirationPhotosynthesis and Respiration

How do Cells Store Energy?How do Cells Store Energy?

Adenosine Triphosphate (ATP) – the molecule where the energy is stored for cell processes.

NADP+ and NADPH- carrier molecules that carry high energy electrons for reactions in the cell.

ATP ModelATP Model

Adenine Ribose 3 Phosphate groups

ATP- ADP CycleATP- ADP Cycle When ATP loses a phosphate group it

releases energy and becomes ADP (Adenosine Diphosphate).

ATP vs. ADP ATP vs. ADP compared to a batterycompared to a battery

ADP ATP

Adenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP)

Partiallychargedbattery

Fullychargedbattery

ATP-ADP CycleATP-ADP Cycle

Energy is added with a

phosphate to ADP

Energy is released with a

phosphate

ATP is formed

ADP is formed

PhotosynthesisPhotosynthesis

Photosynthesis – plants trap the sun’s energy and store it in molecules of glucose. Process of using sun’s energy to make food for the

plant.

Photosynthesis FormulaPhotosynthesis Formula

Process of PhotosynthesisProcess of Photosynthesis

sunlightsunlight

Carbon Dioxide + Water glucose + oxygen Carbon Dioxide + Water glucose + oxygen

chlorophyllchlorophyll

ReactantsReactants Products Products

Photosynthesis takes place in leaves Photosynthesis takes place in leaves (primarily)…(primarily)…

Leaves are the major sites of photosynthesis (although any green vegetation can do so).

Within cells of the leaf, photosynthesis Within cells of the leaf, photosynthesis takes place in the CHLOROPLASTS…takes place in the CHLOROPLASTS…

Elodea cells with small, circular chloroplasts

Thought it didn’t go any smaller?Thought it didn’t go any smaller?

Within those crazy chloroplasts…Within those crazy chloroplasts…

Thylakoids: sacs containing chlorophyll (pancake)

Grana: stack of thylakoid disks (stack of pancakes)

Stroma: the region outside the grana. (syrup)

So where’s the juice?So where’s the juice? Nature of Sunlight—

Light = electromagnetic energy (radiation), travels in rhythmic waves ( wavelengths)

Entire range = electromagnetic spectrum Visible light drives photosynthesis

Photons & PigmentsPhotons & Pigments

Light behaves like individual particles called photons

Light can be absorbed, reflected, transmitted Things that absorb —called pigments Photosynthesis pigments:

chlorophyll a (blue-green) chlorophyll b (yellow-green) carotenoids (yellow-orange)

Two Steps of Two Steps of Photosynthesis:Photosynthesis:

1.1. Light Dependent ReactionLight Dependent Reaction

2.2. Light Independent Reaction Light Independent Reaction (also called Calvin Cycle or (also called Calvin Cycle or Dark Cycle).Dark Cycle).

Light-Dependent Reactions- 1Light-Dependent Reactions- 1stst step step of Photosynthesisof Photosynthesis

Takes place in thylakoid membranes (pancakes).

Requires light energy Sunlight and water enter the grana as

reactants. Oxygen is produced. ATP and NADPH go to the Calvin

Cycle.

Sunlight- reactant

Carbon Dioxide- reactant

Oxygen- product Glucose/Sugar- product

Light-Dependent Reactions

CalvinCycle

NADP+

ADP + P

ATP

NADPH

Water- reactant

22ndnd Step: Light-Independent Step: Light-Independent ReactionsReactions

(Calvin Cycle/Dark Cycle)(Calvin Cycle/Dark Cycle) No light requiredNo light required Takes place in the stroma (syrup)Takes place in the stroma (syrup) Carbon dioxide enters as reactant.Carbon dioxide enters as reactant. Glucose is produced.Glucose is produced. For every 6 molecules of COFor every 6 molecules of CO22, only one , only one

molecule of glucose is formed.molecule of glucose is formed. ADP and NADP+ go to Light Dependent ADP and NADP+ go to Light Dependent

Step.Step.

Sunlight- reactant

Carbon Dioxide- reactant

Oxygen- product Glucose/Sugar- product

Light-Dependent Reactions

CalvinCycle

NADP+

ADP + P

ATP

NADPH

Water- reactant

Cell RespirationCell Respiration

The process where food molecules are broken down The process where food molecules are broken down in the presence of oxygen to release energy.in the presence of oxygen to release energy.

Takes place in mitochondria and cytoplasm.Takes place in mitochondria and cytoplasm. This process may be:This process may be:

Aerobic ( in the presence of oxygen)Aerobic ( in the presence of oxygen) Anaerobic (without oxygen)Anaerobic (without oxygen)

The equation for cellular respiration is:The equation for cellular respiration is:

6O6O22 + C + C66HH1212OO66 6CO6CO22 + 6H + 6H22O + EnergyO + Energy

3 Main Stages of Cell Respiration3 Main Stages of Cell Respiration

1.1. GlycolysisGlycolysis

2.2. Krebs CycleKrebs Cycle

3.3. Electron Transport ChainElectron Transport Chain

GlycolysisGlycolysis

Occurs in cytoplasm Occurs in cytoplasm One molecule of glucose is broken in half, One molecule of glucose is broken in half,

producing pyruvic acids.producing pyruvic acids. 2 molecules of ATP are produced2 molecules of ATP are produced Does not require oxygen (anaerobic)Does not require oxygen (anaerobic)

2 Pyruvic acid

After GlycolysisAfter Glycolysis

If oxygen is present ( aerobic) the second stage If oxygen is present ( aerobic) the second stage is the Krebs cycle.is the Krebs cycle.

If oxygen is not present, glycolysis is followed If oxygen is not present, glycolysis is followed by Fermentation.by Fermentation.

Krebs Cycle Krebs Cycle (also called citric acid cycle)(also called citric acid cycle)

At end of glycolysis about 90% of the chemical At end of glycolysis about 90% of the chemical energy from glucose is still unused. Oxygen needed energy from glucose is still unused. Oxygen needed to extract that energy.to extract that energy.

Aerobic (requires oxygen)Aerobic (requires oxygen) Occurs in mitochondria.Occurs in mitochondria. Pyruvic acid is broken down into carbon dioxide.Pyruvic acid is broken down into carbon dioxide.

Electron Transport ChainElectron Transport Chain

Uses high energy electrons to convert ADP to Uses high energy electrons to convert ADP to ATP ATP

34 more ATP molecules per glucose molecule 34 more ATP molecules per glucose molecule are produced in addition to the 2 ATP are produced in addition to the 2 ATP molecules produced during glycolysis.molecules produced during glycolysis.

Water is also a product.Water is also a product.

Glucose Glycolysis

Cytoplasm

Pyruvic acid

Electrons carried in NADH

Krebs Cycle

Electrons carried in NADH and

FADH2

Electron Transport Chain

Mitochondria

  Respiration: AnOverviewRespiration: AnOverview

Mitochondria

Section 9-1

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FlowchartFlowchartSection 9-2

Glucose(C6H1206)

+Oxygen

(02)

GlycolysisKrebsCycle

ElectronTransport

Chain

Carbon Dioxide

(CO2)+

Water(H2O)

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Cellular Respiration

FermentationFermentation

Releases energy form food molecules in the Releases energy form food molecules in the absence of oxygen (anaerobic)absence of oxygen (anaerobic)

The two main types of Fermentation are :The two main types of Fermentation are : Alcoholic fermentation Alcoholic fermentation Lactic Acid FeremtationLactic Acid Feremtation

Alcoholic FermentationAlcoholic Fermentation

Occurs in yeasts and other microorganisms.Occurs in yeasts and other microorganisms. Converts pyruvic acid to ethyl alcoholConverts pyruvic acid to ethyl alcohol Causes bread to riseCauses bread to rise

Lactic Acid fermentationLactic Acid fermentation

Lactic acid is produced in your muscles during Lactic acid is produced in your muscles during rapid exercise.rapid exercise.

Lack of oxygen to the muscles- causes muscle Lack of oxygen to the muscles- causes muscle soreness.soreness.

Pyruvic acid is converted into lactic acidPyruvic acid is converted into lactic acid

Glucose

Glycolysis Krebs cycle

Electrontransport

Fermentation (without oxygen)

Alcohol or lactic

acid

Chemical PathwaysChemical PathwaysSection 9-1

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