Chapter 4 Cellular Processes. Cellular Energy Cells Use Energy Maintain homeostasis To perform all cellular processes To make energy-storing molecules.

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Chapter 4

Chapter 4Cellular ProcessesCellular Energy2Cells Use EnergyMaintain homeostasisTo perform all cellular processesTo make energy-storing molecules

When they stop using energy,they are deadEnergy RelationshipsEnergy is a one time commodity every time it is used some escapes and becomes unusableMore energy is needed to build an energy-storing molecule than is stored in the molecule. How do organisms obtain their food?Autotrophsauto = selftroph = nourishmentHeterotrophshetero = othersAutotrophsMake their own foodThey capture light energy and convert it into sugarEx: plants, algae, and some bacteria.6HeterotrophsDepend on other organisms for their energy sourceEx: humans, animals, fungi, and most bacteria.7ATP Adenosine TriphosphateMost energy sources (fats, carbohydrates) are large and must be broken down into smaller units (sugar glucose) ATP stores energy in a usable form for all living organismsThe bonds between the three phosphate groups are unstable high-energy covalent bondsATP

Energy ProductionWhen the bonds are broken, a large amount of energy is released (an exothermic reaction) and is available for use in any cellular function that requires energy (an endothermic reaction).ATP ADP + P + Energy

ATPadenosine triphosphatePhosphates123AdenosineATP ProductionADP and P can be reused to form ATP with the proper enzymes and adequate supply of energy ADP + P + Energy ATP12AdenosineADPadenosine diphosphatePhosphatesEnergyATP-ADP Cycle

4A 2 PHOTOSYNTHESISThe process of taking light energy and converting it into stored chemical energy16The sun is the source of energy for living things!

17Photosynthesis Reaction Reaction converting light energy into stored chemical energy6 CO2 + 6 H2O + light energy C6H12O6 + 6 O2(Carbon (water) (glucose) (oxygen)dioxide)

Green plants and algae perform this energy transformation in large enough quantities to provide stored chemical energy for most living organisms

Photosynthesis is important because1) It converts solar energy into usable chemical energy2) It produces oxygen

Light AbsorptionDifferent wavelengths of visible light are seen by the human eye as different colors.The color we see is actually the color reflected.

Chlorophyll a Primary catalyst of photosynthesisGreen pigment in the grana of chloroplastsBecomes activated by light energy22Chlorophyll aChlorophyll a is a blue green pigment it reflects the blues and greens and absorbs the reds and violetsChlorophyll bIs a yellow green pigment that absorbs some of the same pigments as chlorophyll a as well as some of the blues not absorbed by chlorophyll a and reflects some of the yellow greens that chlorophyll a absorbsAbsorption Spectrum

The Process of PhotosynthesisRequires sunlight and waterOccurs in the grana of the chloroplastProduces: Oxygen , ATP and NADPH (electron carrier that stores energy for later use)

The Light-Dependent Phase26Light is NOT required Occurs in the stroma of the chloroplastAlso called:Dark phase, synthetic phase, Calvin cycle, carbon fixation cycleIs dependent upon the products of the light phase (ATP and NADPH) and CO2 from the atmospherePhotosynthesis: The Process Light-Independent Phase27

Conditions for PhotosynthesisProper wavelengths of lightSufficient absorption of carbon dioxideProper temperaturesProper amount of water29Chemosynthesis: Other autotrophsA few bacteria use inorganic chemicals (i.e. ammonia or sulfur) to obtain energyEx. Symbiotic bacteria in tubeworms in hydrothermal vents convert chemical energy in sulfur into usable energy

Cellular RespirationCellular RespirationThe breakdown of a food substance into usable cellular energy in the form of ATPSummaryKinetic energy (sun)stored chemical energy (C6H12O6)= photosynthesisSummary stored chemical energy (C6H12O6)= cellular respirationready-to-use chemical energy ( )Cellular RespirationAerobic Requires oxygen, is the opposite of photosynthesis, combines oxygen with sugar to release energy, carbon dioxide and waterAnaerobicDoes not require oxygenAerobic Cellular Respiration

Aerobic Cellular RespirationC6H12O6 + O2

H2O + CO2 + energy (ATP)The Process of Cellular RespirationGlycolysisCitric Acid Cycle (Krebs Cycle)Hydrogen and Electron Transport System

GlycolysisAll types of cellular respiration begin with glycolysis.Does not require oxygenOccurs in the cytoplasmGlycolysisBreakdown of glucose into pyruvic acid, H+, and electrons2 net ATPAerobic Cellular RespirationThe products from glycolysis are sent to the mitochondria.

Aerobic Cellular Respiration1. Citric Acid Cycle (Krebs Cycle) = Pyruvic acid is broken down into citric acid.Pyruvic acid Acetyl CoAAcetyl CoA Citric acid2. Hydrogen and Electron Transport SystemOccurs in the cristae of the mitochondriaAerobic Cellular Respiration2. Hydrogen and Electron Transport SystemAt the end of the chain, H combines with oxygen to form water.Oxygen is the rate-limiting factor.Aerobic Cellular RespirationEnergy FactsAerobic Cellular Respiration results in the net gain of 36 ATP molecules.

GlycolysisCitric Acid CycleH+ & e- transport systemReactantsProductsLocationATPCytoplasmMitochondria (matrix)Mitochondria(cristae)GlucosePyruvic acid; H+; e-Pyruvic acidCO2; H+; e- H+; e-ATP; water2 net2 net32Anaerobic RespirationBreakdown of food (glucose) without oxygenCellular fermentation2 Types of Fermentation1) Alcoholic fermentation pyruvic acid + NADH alcohol + CO2 + NAD+Ex: yeast 2) Lactic Acid fermentation pyruvic acid + NADH lactic acid + NAD+Ex: produced in your muscles during rapid exercise when the body cannot supply enough oxygen to the tissueEnergy FactsCellular fermentation supplies no ATP energy beyond glycolysis.Energy FactsCellular fermentation supplies no ATP energy beyond glycolysis.Cellular fermentation results in the net gain of 2 ATP molecules.Cellular Respiration

Comparison of Photosynthesis and Cellular RespirationFunctionEnergy CaptureEnergy releaseLocationChloroplastsMitochondriaReactantsCarbon dioxide and waterGlucose and oxygenProductsGlucose and OxygenCarbon dioxide and waterEquations6CO2 + 6H2O + energy C6H12O6 + 6O26O2 + C6H12O6 6CO2 + 6H2O + energyMatch the following: ____1. Organisms that make their own foodA. Chloroplasts____2. Site of photosynthesisB. Aneorobic ____3.Process occurs in a mitochondrionC. Aerobic____4.C6H12O6D. Glucose____5. Process does not require oxygen E. ATP ____6. Process requires oxygenF. Krebs cycle____7.Adenosine diphosphateG. Glycolysis____8.Energy storing moleculeH. Energy____9. The anaerobic process of splitting glucose and forming two molecules of pyruvic acid I. ADP ____10. The ability to do work J. Autotrophs

WORD BANK2 ATP2 ATP36 ATP6 NADH2 FADHElectron transport chainMitochondrionCytoplasmFermentationGlycolysisGlucosePyruvateLactic acidKreb's Cycle


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