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Cellular EnergyCellular Energy

Photosynthesis and Cellular Photosynthesis and Cellular RespirationRespiration

PhotosynthesisPhotosynthesis

Basic reaction:Basic reaction:

6 CO6 CO22 + 12 H + 12 H22O + light energy, chlorophyll, enzymes O + light energy, chlorophyll, enzymes →→

CC66HH1212OO6 6 + 6 O + 6 O22 + 6 H + 6 H22OO

Rate varies withRate varies with Availability of raw materialsAvailability of raw materials Intensity of sunlightIntensity of sunlight Temperature (best at 20-35Temperature (best at 20-35°C / 68 - 95°F)°C / 68 - 95°F)


PigmentsPigments ChlorophyllChlorophyll

Chlorophyll aChlorophyll a and and chlorophyll bchlorophyll b most common most common types.types.

Captures light energy and feeds it into Captures light energy and feeds it into photosynthetic process photosynthetic process

XanthophyllsXanthophylls Yellow pigments that capture light energy and Yellow pigments that capture light energy and

transfer it to chlorophyll a.transfer it to chlorophyll a. CarotenesCarotenes

Orange pigments that capture light energy and Orange pigments that capture light energy and transfer it to chlorophyll a.transfer it to chlorophyll a.


Light ReactionsLight Reactions Light energy transferred from chlorophyll a is Light energy transferred from chlorophyll a is

used to used to Convert some ADP to ATPConvert some ADP to ATP Split HSplit H22O into Oxygen and O into Oxygen and High EnergyHigh Energy Hydrogen Hydrogen

ions (in the form of NADHions (in the form of NADH++).). Oxygen is released into the atmosphere.Oxygen is released into the atmosphere. ATP and Hydrogen ions are used to "fuel" the ATP and Hydrogen ions are used to "fuel" the

Dark Reactions


Dark Reactions One atom of Oxygen is split from CO2. This

atom combines with 2 Hydrogen ions to form H2O.

Remaining Carbon and Oxygen group combine with remaining Hydrogen ions to enter the Calvin Cycle and eventually form Glucose (C6H12O6).


Hydrogen Hydrogen ions ions (NADH)(NADH)

Cellular RespirationCellular Respiration

The process of converting stored chemical The process of converting stored chemical energy in food molecules to chemical energy in food molecules to chemical energy in the form of ATP that is usable energy in the form of ATP that is usable for all cellular activities.for all cellular activities.

A two stage process:A two stage process: Stage 1 is Stage 1 is ALWAYSALWAYS glycolysis glycolysis Stage 2 is eitherStage 2 is either

Aerobic respiration (with oxygen)Aerobic respiration (with oxygen) Anaerobic respiration (without oxygen)Anaerobic respiration (without oxygen)


ALL living organisms carry on cellular ALL living organisms carry on cellular respiration to provide energy for life respiration to provide energy for life processes.processes. Autotrophs carry on cellular respirationAutotrophs carry on cellular respiration Heterotrophs carry on cellular respirationHeterotrophs carry on cellular respiration

REMEMBER … even plants carry on REMEMBER … even plants carry on cellular respirationcellular respiration


GLYCOLYSISGLYCOLYSIS Glycolysis is the breakdown of glucose to Glycolysis is the breakdown of glucose to

form 2 molecules of pyruvate.form 2 molecules of pyruvate. This process occurs in the cytoplasm of the cell.This process occurs in the cytoplasm of the cell. This process uses 2 molecules of ATP and makes This process uses 2 molecules of ATP and makes

4 molecules of ATP to yield a total gain of 2 ATP.4 molecules of ATP to yield a total gain of 2 ATP.

CELLULAR RESPIRATION CELLULAR RESPIRATION ALWAYSALWAYS BEGINS WITH GLYCOLYSIS!!!!!BEGINS WITH GLYCOLYSIS!!!!!


The second stage of cellular respiration The second stage of cellular respiration will take one of two paths depending on will take one of two paths depending on whether oxygen is present or absent in the whether oxygen is present or absent in the cell.cell.

If oxygen is present, If oxygen is present, aerobicaerobic respiration respiration occurs in the mitochondrion of the cell occurs in the mitochondrion of the cell producing a LOT of ATP.producing a LOT of ATP.

If oxygen is If oxygen is notnot present, present, anaerobicanaerobic respiration occurs in the cytoplasm of the respiration occurs in the cytoplasm of the cell producing NO additional ATP.cell producing NO additional ATP.


AEROBIC RESPIRATIONAEROBIC RESPIRATION Takes place in the mitochondria of the cellTakes place in the mitochondria of the cell Pyruvate produced in glycolysis enters the Pyruvate produced in glycolysis enters the

mitochondria and a carbon molecule is mitochondria and a carbon molecule is removed. This carbon combines with oxygen removed. This carbon combines with oxygen to produce a molecule of COto produce a molecule of CO22..

The remaining portion of the pyruvate is now The remaining portion of the pyruvate is now called an acetyl group. It combines with a called an acetyl group. It combines with a molecule called Coenzyme-A to form a molecule called Coenzyme-A to form a molecule called acetyl-CoAmolecule called acetyl-CoA


AEROBIC RESPIRATIONAEROBIC RESPIRATION Acetyl-CoA enters the Acetyl-CoA enters the Krebs CycleKrebs Cycle. . The Krebs Cycle will produce 2 more ATP, The Krebs Cycle will produce 2 more ATP,

and will "energize" 3 molecules of NADH and and will "energize" 3 molecules of NADH and 1 molecule of FADH1 molecule of FADH22..

The NADH and FADHThe NADH and FADH22 enter an electron enter an electron

transport chain in the mitochondrial transport chain in the mitochondrial membrane to produce another membrane to produce another 3434 ATP. ATP.

Oxygen is needed to keep the electron Oxygen is needed to keep the electron transport chain running. It combines with transport chain running. It combines with Hydrogen to form water.Hydrogen to form water.


AEROBIC RESPIRATIONAEROBIC RESPIRATION Total ATP produced:Total ATP produced:

Glycolysis = 2 ATPGlycolysis = 2 ATP Krebs Cycle = 2 ATPKrebs Cycle = 2 ATP Electron Transport Chain = 34 ATPElectron Transport Chain = 34 ATP Grand Total = 38 ATPGrand Total = 38 ATP

CC66HH1212OO6 6 + 6 O + 6 O22 + 6 H + 6 H22OO→→6 CO2 + 12 H6 CO2 + 12 H22O + 38 ATPO + 38 ATP


ANAEROBIC RESPIRATIONANAEROBIC RESPIRATION If oxygen is not present in the cell, the If oxygen is not present in the cell, the

electron transport chain will not function. electron transport chain will not function. Instead of entering the Krebs Cycle, the Instead of entering the Krebs Cycle, the pyruvate produced in glycolysis will undergo pyruvate produced in glycolysis will undergo fermentationfermentation..

Two important types of fermentation areTwo important types of fermentation are Lactic acid fermentationLactic acid fermentation Alcoholic fermentationAlcoholic fermentation


ANAEROBIC RESPIRATIONANAEROBIC RESPIRATION The end result of lactic acid fermentation is The end result of lactic acid fermentation is

lactic acid (also called lactate)lactic acid (also called lactate) Some bacteria and fungi act anaerobically on Some bacteria and fungi act anaerobically on

sugars in foods to produce other foods including:sugars in foods to produce other foods including: cheesecheese yogurtyogurt buttermilkbuttermilk

Low levels of oxygen in muscle cells during heavy Low levels of oxygen in muscle cells during heavy exercise results in anaerobic respiration and the exercise results in anaerobic respiration and the buildup of lactic acid. This is what causes your buildup of lactic acid. This is what causes your muscles to become sore.muscles to become sore.


ANAEROBIC RESPIRATIONANAEROBIC RESPIRATION The end result of alcoholic fermentation is The end result of alcoholic fermentation is

ethyl alcohol (ethanol) and carbon dioxide.ethyl alcohol (ethanol) and carbon dioxide. Many yeasts ferment (anaerobic respiration) the Many yeasts ferment (anaerobic respiration) the

sugars in grains to produce other useful items:sugars in grains to produce other useful items: baked goods such as bread that require dough to rise.baked goods such as bread that require dough to rise. beer and wine (12% alcohol or less)beer and wine (12% alcohol or less) "hard" liquors (require further distillation to achieve "hard" liquors (require further distillation to achieve

alcohol concentrations >12%)alcohol concentrations >12%) fuel for engines.fuel for engines.


ANAEROBIC RESPIRATIONANAEROBIC RESPIRATION Anaerobic respiration does not produce any Anaerobic respiration does not produce any

more ATP for the cell to use. more ATP for the cell to use. The total yield of ATP from anaerobic The total yield of ATP from anaerobic

respiration is the 2 ATP produced during respiration is the 2 ATP produced during glycolysis.glycolysis.

The "extra" ATP that could have been The "extra" ATP that could have been produced is still stored in the end products of produced is still stored in the end products of fermentation.fermentation.

Ethanol is a race car fuelEthanol is a race car fuel Cheese is a high energy foodCheese is a high energy food