chapter 9. chemical energy and food living things get the energy they need from food. the process of...
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Cellular RespirationChapter 9
Chemical Energy and FoodLiving things get the energy they need from
food.The process of releasing the energy stored in
food is cellular respiration.
Overview of Cellular Respiration
In the presence of oxygen, aerobic respiration takes place.This produces 36 ATP per molecule of glucose.
In the absence of oxygen, anaerobic respiration (fermentation) takes place.This produces 2 ATP per molecule of glucose.
Glucose
Glycolysis Krebs cycle
Electrontransport
Fermentation (without oxygen)
Alcohol or lactic
acid
Chemical PathwaysSection 9-1
GlycolysisBoth aerobic and anaerobic respiration begin
with a process known as glycolysis.This means “glucose -splitting”
This takes place in the cytoplasm.
Glucose
To the electron transport
chain
GlycolysisSection 9-1
2 Pyruvic acid
Glucose
To the electron transport
chain
GlycolysisSection 9-1
2 Pyruvic acid
Glucose
To the electron transport
chain
GlycolysisSection 9-1
2 Pyruvic acid
GlycolysisIf oxygen is available, the pyruvic acid
molecules will be broken down further to release more energy.
If oxygen is unavailable, the pyruvic acid molecules will be converted to a waste product with no further release of energy (fermentation).
Glucose
Glycolysis Krebs cycle
Electrontransport
Fermentation (without oxygen)
Alcohol or lactic
acid
Chemical PathwaysSection 9-1
FermentationAlso known as anaerobic respiration.Two types:
Alcoholic fermentation – in yeasts Pyruvic acid is converted to alcohol and carbon
dioxide.
Lactic acid fermentation – in bacteria and muscle cells Pyruvic acid is converted to lactic acid.
Glucose Pyruvic acidLactic acid
Section 9-1
Lactic Acid Fermentation
Aerobic Respiration
6O2 + C6H12O6 6CO2 + 6H2O + 36 ATPOxygen + glucose carbon dioxide + water
+ energy
GlucoseGlycolysis
Cytoplasm
Pyruvic acid
Electrons carried in NADH
Krebs Cycle
Electrons carried in NADH and
FADH2 Electron Transport
Chain
Mitochondrion
Mitochondrion
Mitochondrial Reactions
FlowchartSection 9-2
Glucose(C6H1206)
+Oxygen
(02)
GlycolysisKrebsCycle
ElectronTransport
Chain
Carbon Dioxide(CO2)
+Water(H2O)
Aerobic Cellular Respiration
Aerobic RespirationIn the presence of oxygen, pyruvic acid is
further broken down to release additional energy.
This takes place in the mitochondria.There are two steps:
1. The Krebs Cycle2. The electron transport chain
The Krebs Cycle
Also known as the citric acid cycle.1. Pyruvic acid (from glycolysis) is broken down
into carbon dioxide.2. High energy electrons are captured by NAD
and FAD and brought to the electron transport chain.
Net gain of 2 ATP from this cycle.
Citric Acid Production
The Krebs CycleSection 9-2
Mitochondrion
Electron Transport ChainNADH and FADH2 drop off high energy
electrons.These pass through a series of reactions
located on the inner membrane that produce ATP.
Oxygen combines with hydrogen to make water.
Net gain of ATP = 32
Electron Transport ChainSection 9-2
Electron TransportHydrogen Ion Movement
ATP Production
ATP synthase
Channel
Inner Membrane
Matrix
Intermembrane Space
Mitochondrion
ATP totalsGlycolysis – 2Krebs Cycle – 2Electron Transport Chain – 32
Net: from one glucose molecule = 36 ATP
Photosynthesis & Cellular RespirationPhotosynthesis Cellular
Respiration
Function Energy capture Energy release
Location Chloroplasts Mitochondria
Reactants CO2 & H2O C6H12O6 & O2
Products C6H12O6 & O2 CO2 and H2O
Equation 6CO2 + 6H2O C6H12O6 + 6O2
6O2 + C6H12O6 6CO2 + 6H2O