Cells UnitCells Unit

Learning Goal #4: Describe the flow of energy and matter in cellular function.

All Living All Living Things Things Require Require Energy to Energy to Function. Function.

Adenosine TriphosphateAdenosine Triphosphate“ATP”“ATP”

One ATP Molecule

•This molecule acts as the short-term energy currency of the cell and provides the source of energy used in reactions. •ATP collects small packets of energy from the food-burning power plants of the cell and transports this energy to where it is needed. •Some energy in ATP is released to do work, such as move muscles or force a seedling out of the ground.

PhotosynthesisPhotosynthesis

Photosynthesis OverviewPhotosynthesis OverviewProcess by which plants and

other autotrophs store the energy of sunlight as sugars.

Requires sunlight, water, and carbon dioxide.

Overall equation:

6 CO2 + 6 H20 C6H12O6 + 6 O2

Occurs in the leaves of plants in organelles called chloroplasts.

Photosynthesis: Photosynthesis: The Chemical ProcessThe Chemical Process

Occurs in two main phases.◦Light reactions◦Dark reactions (aka – the Calvin Cycle)

Light reactions are the “photo” part of photosynthesis. Light is absorbed by pigments.

Dark reactions are the “synthesis” part of photosynthesis. Trapped energy from the sun is converted to the chemical energy of sugars.

Light ReactionsLight Reactions

Light-dependent reactions occur on the thylakoid membranes.◦Light and water are required for this process.

◦Energy storage molecules are formed. (ATP and NADPH)

◦Oxygen gas is made as a waste product.

Dark ReactionsDark Reactions

Dark reactions (light-independent) occur in the stroma.◦Carbon dioxide is “fixed” into the sugar glucose.

◦ ATP and NADPH molecules created during the light reactions power the production of this glucose.

EQUATIONEQUATION FORFOR PHOTOSYNTHESISPHOTOSYNTHESIS

6CO6CO22 + + 6H6H22OO + +ENERGYENERGY CC66HH1212OO66 + + 6O6O22

CARBON CARBON DIOXIDEDIOXIDE

WATERWATER

GLUCOSEGLUCOSE

OXYGENOXYGEN

Chemical Energy & FoodChemical Energy & Food

One gram of glucose = 3811 calories

1 calorie = amount of energy needed to heat 1 gram of water 1 degree Celsius

Food calories are measured in Calories where 1 Calorie = 1000 calories.

Cellular RespirationCellular Respiration

Cellular Respiration is the process that releases energy by breaking down food molecules in the presence of oxygen.

6O2 + C6H12O6 6CO2 + 6H2O + Energy

Oxygen + Glucose Carbon Dioxide + Water + Energy

EQUATION FOREQUATION FOR RESPIRATIONRESPIRATION

CC66HH1212OO66 ++

GLUCOSEGLUCOSE

6O6O22

OXYGENOXYGEN

6CO6CO22 ++

CARBON CARBON DIOXIDEDIOXIDE

6H6H22OO ++

ENERGYENERGY

WATERWATER

ATPATP

GlycolysisGlycolysis

Glycolysis is the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid.

2 ATP needed to start reaction, 4 ATP are produced thus the net gain is 2 ATP.

Anaerobic Cellular Anaerobic Cellular Respiration Respiration

FermentationFermentationNo Oxygen required= AnaerobicReleases energy from glucose without

the presence of oxygen.There are two types of fermentation:

alcoholic and lactic acid.Alcoholic fermentation is done by

yeasts and some microorganisms. It produces alcohol & Carbon Dioxide

Lactic Acid is produced by muscles during rapid exercise when the body cannot supply enough oxygen.

Aerobic Cellular Respiration Aerobic Cellular Respiration

Oxygen required=aerobic2 more sets of reactions which occur

in a specialized structure within the cell called the mitochondria◦1. Kreb’s Cycle◦2. Electron Transport Chain

The Krebs CycleThe Krebs Cycle

During the Krebs Cycle, pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions.

Citric Acid is created in this cycle thus giving it the nickname Citric Acid cycle.

Net ATP Production is 2 ATP.

Electron Transport ChainElectron Transport Chain

The electron transport chain uses the high-energy electrons from the Krebs Cycle to convert ADP to ATP.

Total ATP 32.

Energy TallyEnergy Tally

36 ATP for aerobic vs. 2 ATP for anaerobic

◦Glycolysis 2 ATP

◦Kreb’s 2 ATP

◦Electron Transport 32 ATP 36 ATP

Anaerobic organisms can’t be too energetic but are important for global recycling of carbon

Energy & ExerciseEnergy & Exercise

Quick energy (anaerobic) – Lactic Acid fermentation is used to get quick energy and gives off lactic acid as a by product, thus the muscle pain.

Long-Term Energy (aerobic) – Use cellular respiration to produce energy. Exercising or activities that last for at least 15 to 20 minutes. Best form for weight control.

Overview of photosynthesis Overview of photosynthesis and respirationand respiration

PHOTOSYNTHESISPHOTOSYNTHESIS CELLCELLACTIVITIESACTIVITIES

RESPIRATIONRESPIRATION

SUNSUN

RADIANT RADIANT ENERGYENERGY

GLUCOSEGLUCOSE ATP(ENERGY)ATP(ENERGY)

Comparing Comparing Photosynthesis & RespirationPhotosynthesis & Respiration

PhotosynthesisPhotosynthesis Cellular Cellular RespirationRespiration

FunctionFunction Energy StorageEnergy Storage Energy Energy ReleaseRelease

LocationLocation ChloroplastsChloroplasts MitochondriaMitochondria

Reactants Reactants COCO22 and H and H22OO CC66HH1212OO66 and and OO22

ProductsProducts CC66HH1212OO66 and O and O22 COCO22 and H and H22OO

EquationEquation 6CO6CO22 + 6H + 6H22O O CC66HH1212OO66 + 6O + 6O22

CC66HH1212OO66 + 6O + 6O22

6CO6CO22 + 6H + 6H22OO