Presentation on theme: "Energy Flow Through Living Things: Photosynthesis & Cellular Respiration Chapter 8&9."— Presentation transcript:
1Energy Flow Through Living Things: Photosynthesis & Cellular Respiration Chapter 8&9
28-1 Energy and Life Living things need energy to survive comes from foodenergy in most food comes from the sunPlants use light energy from the sun to produce foodautotrophs organisms that make their own foodEx - plantsheterotrophs organisms that must obtain energy from the foods they consumeanimals
3Chemical Energy and ATP Energy – the ability to do workForms: light, heat, electricity, chemical compoundschemical compound that cells use to store and release energy is adenosine triphosphate (ATP)ATP - basic energy source for all cells
4Chemical Energy and ATP The three phosphate groups are the key to ATP's ability to store and release energy.ATP consists of:adenineribose (a 5-carbon sugar)3 phosphate groupsAdenineRibose3 Phosphate groupsATP is used by all types of cells as their basic energy source.ATP
5Chemical Energy and ATP Storing EnergyADP has two phosphate groups instead of three.A cell can store small amounts of energy by adding a phosphate group to ADP.ATPADPEnergy+EnergyAdenosine Triphosphate (ATP)Adenosine Diphosphate (ADP) + PhosphatePartially charged batteryFully charged battery
6Chemical Energy and ATP Releasing EnergyEnergy stored in ATP is released by breaking the chemical bond between the second and third phosphates.2 Phosphate groupsPADP
7Chemical Energy and ATP ATP energy uses:cellular activities: active transport, protein synthesismuscle contractionMost cells have only a small amount of ATP, because it is not a good way to store large amounts of energy.Cells can regenerate ATP from ADP as needed by using the energy in foods like glucose.
88-2 PhotosynthesisPhotosynthesis - the process in which green plants use the energy of sunlight to convert water and carbon dioxide into high-energy carbohydrates and oxygen
9The Photosynthesis Equation The equation for photosynthesis is:6CO2 + 6H2O C6H12O6 + 6O2carbon dioxide + water sugars + oxygenLightLight
10The Photosynthesis Equation Light energyH2OLight-Dependent Reactions (thylakoids)O2ADP NADP+ATP NADPHPhotosynthesis is a series of reactions that uses light energy from the sun to convert water and carbon dioxide into sugars and oxygen.CO2 + H20SugarCalvin Cycle (stroma)
11Light and Pigments photosynthesis requires chlorophyll pigments - light-absorbing molecules that gather the sun's energyThe main pigment in plants is chlorophyll.There are two main types of chlorophyll:chlorophyll achlorophyll b
12Light and PigmentsChlorophyll absorbs light well in the blue-violet and red regions of the visible spectrum.10080604020Chlorophyll bEstimated Absorption (%)Chlorophyll aPhotosynthesis requires light and chlorophyll. In the graph above, notice how chlorophyll a absorbs light mostly in the blue-violet and red regions of the visible spectrum, whereas chlorophyll b absorbs light in the blue and red regions of the visible spectrum.Wavelength (nm)Wavelength (nm)
13Light and PigmentsChlorophyll does not absorb light will in the green region of the spectrum. Green light is reflected by leaves, which is why plants look green.10080604020Chlorophyll bEstimated Absorption (%)Chlorophyll aPhotosynthesis requires light and chlorophyll. In the graph above, notice how chlorophyll a absorbs light mostly in the blue-violet and red regions of the visible spectrum, whereas chlorophyll b absorbs light in the blue and red regions of the visible spectrum.Wavelength (nm)
14Light Energy Light is a form of energy compound that absorbs light also absorbs energy from that lightchlorophyll absorbs light the energy is transferred directly to electrons in the chlorophyll molecule raising the energy levels of these electronshigh-energy electrons are what make photosynthesis work
15Pop Quiz Word Bank ADP Ribose Phosphate groups Bonds ATP AdenineAdenosineThis molecule is called _____.Energy in this molecule is stored in the _____.3.5.4.
168-3 Inside a Chloroplast Inside a Chloroplast In plants, photosynthesis takes place inside chloroplasts.PlantChloroplastPlant cells
17Inside a ChloroplastChloroplasts contain thylakoids—saclike photosynthetic membranes.SinglethylakoidChloroplast
18Inside a ChloroplastThylakoids are arranged in stacks known as grana. A singular stack is called a granum.Stroma – space outside of the thylakoidsGranumStromaChloroplast
19Inside a ChloroplastProteins in the thylakoid membrane organize chlorophyll and other pigments into clusters called photosystems, which are the light-collecting units of the chloroplast.PhotosystemsChloroplast
20Photosynthesis Reactions reactions of photosystems include:light-dependent reactions (requires light)take place within the thylakoid membranesuses water, ADP, and NADP+produces oxygen, ATP, and NADPHlight-independent reactions (Calvin cycle)takes place in the stromaATP and NADPH not stable enough to store the energy they carry for more than a few minutesuses ATP and NADPH energy to build high-energy sugars for long term storage
21Photosynthesis Reactions The two sets of photosynthetic reactions work together.The light-dependent reactions trap sunlight energy in chemical form.The light-independent reactions use that chemical energy to produce stable, high-energy sugars from carbon dioxide and water.
22Light- dependent reactions Inside a ChloroplastH2OCO2LightNADP+ADP + PLight- dependent reactionsCalvin CycleCalvin cycleThe process of photosynthesis includes the light-dependent reactions as well as the Calvin cycle.ChloroplastO2Sugars
23Electron Carrierselectrons in chlorophyll absorb sunlight electrons gain energyCells use electron carriers to transport these high-energy electrons from chlorophyll to other moleculesOne carrier molecule is NADP+.transport electronsNADP+ accepts and holds 2 high-energy electrons along with a hydrogen ion (H+) - NADP+ NADPHenergy of sunlight can be trapped in chemical formNADPH carries high-energy electrons to chemical reactions elsewhere in the cell to make carbohydrates
24Factors Affecting Photosynthesis Many factors affect the rate of photosynthesis, including:WaterTemperatureIntensity of light
27Chemical Energy and Food One gram of the sugar glucose (C6H12O6), when burned in the presence of oxygen, releases 3811 calories of heat energycalorie - the amount of energy needed to raise the temperature of 1 gram of water 1 degree CelsiusCells gradually release the energy from glucose and other food compounds beginning with glycolysis - releases a small amount of energy.
28Overview of Cellular Respiration If oxygen is present:cellular respiration - the process that releases energy by breaking down glucose and other food molecules in the presence of oxygenglycolysis Krebs cycle electron transport chainequation:6O2 + C6H12O6 → 6CO2 + 6H2O + Energyoxygen + glucose → carbon dioxide + water + Energy
29Overview of Cellular Respiration Electrons carried in NADHElectrons carriedin NADH andFADH2Pyruvic acidGlucoseGlycolysisCytoplasmCellular respiration is the process that releases energy by breaking down food molecules in the presence of oxygen. Glycolysis takes place in the cytoplasm. The Krebs cycle and electron transport take place inside the mitochondria.Mitochondrion
30Overview of Cellular Respiration Glycolysis – cytoplasmKrebs cycle and electron transport - mitochondriaGlycolysisCellular respiration is the process that releases energy by breaking down food molecules in the presence of oxygen. Glycolysis takes place in the cytoplasm. The Krebs cycle and electron transport take place inside the mitochondria.CytoplasmMitochondrion
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32Glycolysisthe process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid, a 3-carbon compoundATP Productioncell uses up 2 molecules of ATP to start the reactionWhen glycolysis is complete, 4 ATP molecules have been produced a net gain of 2 ATP moleculesNADH Productionremoves 4 high-energy electrons electron carrier called NAD+ becomes an NADH molecule.The NADH molecule holds the electrons until they can be transferred to other molecules.
33Glycolysis 2 ATP 2 ADP 4 ADP 4 ATP Glucose 2 Pyruvic acid Glycolysis is the first stage in cellular respiration. During glycolysis, glucose is broken down into 2 molecules of pyruvic acid.Glucose2 Pyruvicacid
38Glycolysis 2NAD+ 2 ATP 2 ADP 4 ADP 4 ATP 2 Pyruvic acid 2 To the electron transport chain
39Glycolysis The Advantages of Glycolysis very fast - cells can produce thousands of ATP molecules in a few millisecondsdoes not require oxygen
40Fermentationoxygen is not present glycolysis is followed by a different pathway - fermentationFermentation – release of energy (ATP) from food in the absence of oxygencells convert NADH to NAD+ by passing high-energy electrons back to pyruvic acidAnaerobic – does not require oxygen
41Fermentation Alcoholic Fermentation equation: Yeasts and a few other microorganisms use alcoholic fermentationForms ethyl alcohol and carbon dioxide as wastesequation:pyruvic acid + NADH → alcohol + CO2 + NAD+
42Fermentation Lactic Acid Fermentation pyruvic acid that accumulates from glycolysis converted to lactic acidregenerates NAD+ so that glycolysis can continueconverts glucose into lactic acidequation:pyruvic acid + NADH → lactic acid + NAD+
43Fermentation The first part of the equation is glycolysis. Lactic acid fermentation converts glucose into lactic acid. The first part of the equation is glycolysis. The second part shows the conversion of pyruvic acid to lactic acid.
44FermentationThe second part shows the conversion of pyruvic acid to lactic acid.Lactic acid fermentation converts glucose into lactic acid. The first part of the equation is glycolysis. The second part shows the conversion of pyruvic acid to lactic acid.
45The TotalsThe complete breakdown of glucose through cellular respiration, including glycolysis, results in the production of 36 molecules of ATP.
46Comparing Photosynthesis and Cellular Respiration The energy flows in photosynthesis and cellular respiration take place in opposite directions.
47Comparing Photosynthesis and Cellular Respiration On a global level, photosynthesis and cellular respiration are also opposites.Photosynthesis removes carbon dioxide from the atmosphere and cellular respiration puts it back.Photosynthesis releases oxygen into the atmosphere and cellular respiration uses that oxygen to release energy from food.