Cellular Respiration
description
Transcript of Cellular Respiration
![Page 1: Cellular Respiration](https://reader035.fdocuments.us/reader035/viewer/2022062811/568161cd550346895dd1b9d7/html5/thumbnails/1.jpg)
Cellular RespirationCampbell Ch. 9
![Page 2: Cellular Respiration](https://reader035.fdocuments.us/reader035/viewer/2022062811/568161cd550346895dd1b9d7/html5/thumbnails/2.jpg)
Life Requires Energy
• Energy flows into an ecosystem as sunlight and leaves as heat
• Photosynthesis
• Cells use chemical energy stored in organic molecules = cellular respiration
![Page 3: Cellular Respiration](https://reader035.fdocuments.us/reader035/viewer/2022062811/568161cd550346895dd1b9d7/html5/thumbnails/3.jpg)
Lightenergy
ECOSYSTEM
Photosynthesisin chloroplasts
Cellular respirationin mitochondria
CO2 H2O O2Organic
molecules
ATP powersmost cellular workATP
Heatenergy
![Page 4: Cellular Respiration](https://reader035.fdocuments.us/reader035/viewer/2022062811/568161cd550346895dd1b9d7/html5/thumbnails/4.jpg)
Cellular Respiration Generates ATP
• Cellular respiration includes both aerobic and anaerobic respiration but is often used to refer to aerobic respiration
• Although carbohydrates, fats, and proteins are all consumed as fuel, it is simplest to trace cellular respiration with the sugar glucose
C6H12O6 + 6 O2 6 CO2 + 6 H2O + Energy (ATP + heat)
![Page 5: Cellular Respiration](https://reader035.fdocuments.us/reader035/viewer/2022062811/568161cd550346895dd1b9d7/html5/thumbnails/5.jpg)
Redox Reactions: Oxidation and Reduction
• The transfer of electrons during chemical reactions releases energy stored in organic molecules
• This released energy is ultimately used to synthesize ATP
![Page 6: Cellular Respiration](https://reader035.fdocuments.us/reader035/viewer/2022062811/568161cd550346895dd1b9d7/html5/thumbnails/6.jpg)
The Principle of Redox• Chemical reactions that transfer electrons
between reactants are called oxidation-reduction reactions, or redox reactions
• In oxidation, a substance loses electrons, or is oxidized
• In reduction, a substance gains electrons, or is reduced (the amount of positive charge is reduced)
• During cellular respiration, the fuel (such as glucose) is oxidized, and O2 is reduced
![Page 7: Cellular Respiration](https://reader035.fdocuments.us/reader035/viewer/2022062811/568161cd550346895dd1b9d7/html5/thumbnails/7.jpg)
Harvesting Energy in Small Steps
• In cellular respiration, glucose and other organic molecules are broken down in a series of steps
• Electrons from organic compounds are usually first transferred to NAD+, a coenzyme
• NADH passes the electrons to the electron transport chain
• Unlike an uncontrolled reaction, the electron transport chain passes electrons in a series of steps instead of one explosive reaction
• The energy yielded is used to regenerate ATP
![Page 8: Cellular Respiration](https://reader035.fdocuments.us/reader035/viewer/2022062811/568161cd550346895dd1b9d7/html5/thumbnails/8.jpg)
Figure 9.5
(a) Uncontrolled reaction (b) Cellular respiration
Explosiverelease of
heat and lightenergy
Controlledrelease ofenergy for
synthesis ofATP
Free
ene
rgy,
G
Free
ene
rgy,
G
H2 1/2 O2 2 H 1/2 O2
1/2 O2
H2O H2O
2 H+ 2 e
2 e
2 H+
ATP
ATP
ATP
Electron transport
chain
(from food via NADH)
![Page 9: Cellular Respiration](https://reader035.fdocuments.us/reader035/viewer/2022062811/568161cd550346895dd1b9d7/html5/thumbnails/9.jpg)
The Stages of Cellular Respiration
• Harvesting of energy from glucose has three stages
– Glycolysis (breaks down glucose into two molecules of pyruvate)
– The citric acid cycle (completes the breakdown of glucose)
– Oxidative phosphorylation (accounts for most of the ATP synthesis)
![Page 10: Cellular Respiration](https://reader035.fdocuments.us/reader035/viewer/2022062811/568161cd550346895dd1b9d7/html5/thumbnails/10.jpg)
Figure 9.6-1
Electronscarried
via NADH
Glycolysis
Glucose Pyruvate
CYTOSOL MITOCHONDRION
ATP
Substrate-levelphosphorylation
![Page 11: Cellular Respiration](https://reader035.fdocuments.us/reader035/viewer/2022062811/568161cd550346895dd1b9d7/html5/thumbnails/11.jpg)
Figure 9.6-2
Electronscarried
via NADH
Electrons carriedvia NADH and
FADH2
Citricacidcycle
Pyruvateoxidation
Acetyl CoA
Glycolysis
Glucose Pyruvate
CYTOSOL MITOCHONDRION
ATP ATP
Substrate-levelphosphorylation
Substrate-levelphosphorylation
![Page 12: Cellular Respiration](https://reader035.fdocuments.us/reader035/viewer/2022062811/568161cd550346895dd1b9d7/html5/thumbnails/12.jpg)
Figure 9.6-3
Electronscarried
via NADH
Electrons carriedvia NADH and
FADH2
Citricacidcycle
Pyruvateoxidation
Acetyl CoA
Glycolysis
Glucose Pyruvate
Oxidativephosphorylation:electron transport
andchemiosmosis
CYTOSOL MITOCHONDRION
ATP ATP ATP
Substrate-levelphosphorylation
Substrate-levelphosphorylation
Oxidative phosphorylation