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Respiration
How Is a Marathoner Different from a
Sprinter?
Aerobic vs. anaerobic
Aerobic vs. Anaerobic
Anaerobic pathways Aerobic pathways
• Older
• No O
• In cytoplasm
•
•
•
•
Newer
Require O
Start in cytoplasm
Completed in
mitochondria
Food Sources
• Autotrophs (producers)
• Hetrotrophs (consumers)
• Both make ATP
Sunlight energy
ECOSYSTEM
Photosynthesis in
chloroplasts
Glucose
CO2
+
+
H2O
O2
Cellular respiration in mitochondria
ATP
(for cellular work)
Heat energy
Energy Consumption
Why Breathe?
O2
Breathing
CO2
Lungs
CO2
Bloodstream
O2
Muscle cells carrying out
Cellular Respiration
Glucose + O2
CO2 + H2O + ATP
Summary Equation for
Aerobic Respiration
C6H12O6
Glucose
+
6
O2
Oxygen gas
6
CO2
Carbon
dioxide
+
6
H2O
Water
+
ATPs
Energy
Electron Transfers
• Oxidation - lose electron
• Reduction - gain electron
Loss of hydrogen atoms
(oxidation)
C6H12O6 + 6 O2
6 CO2
+
Glucose
6 H2O + Energy
(ATP)
Gain of hydrogen atoms
(reduction)
Coenzymes
• NAD+ and FAD
• NADH and FADH2
• Carry electrons and hydrogen
Coenzymes
Oxidation
H
O
NAD+
O + 2H
H
Dehydrogenase
Reduction
NADH
2H
+
+
2H
+
2e

(carries
2 electrons)
+
H+
ETC
NADH
NAD
+
H
+
ATP

2e
+
Controlled
release of
energy for
synthesis of
ATP

2e
2
H
1
+
2
H2O
O2
Overview
NADH
High-energy
electrons
carried by NADH
NADH
FADH2
and
GLYCOLYSIS
Glucose
Pyruvate
CITRIC ACID
CYCLE
OXIDATIVE
PHOSPHORYLATION
(Electron Transport
and Chemiosmosis)
Mitochondrion
Cytoplasm
ATP
Substrate-level
phosphorylation
Figure 6.6
CO2
ATP
CO2
Substrate-level
phosphorylation
ATP
Oxidative
phosphorylation
Glucose
• C6H12O6
In-text figure
Page 136
Glycolysis
glucose
GLYCOLYSIS
pyruvate
animal cell (eukaryotic)
plant cell (eukaryotic)
bacterial cell (prokaryotic)
Figure 8.4(1)
Page 136
Slide 7
Glycolysis
• Two stages
• Energy-requiring steps
– 2 ATP
– Transfers P group
• Energy-releasing steps
– Splits activated glucose
– Forms 2 pyruvate, 4 ATP and 2 NADH
Glycolysis
2
NAD+
2
NADH
+ 2
H+
Glucose
2 Pyruvate
2 ADP
+2
P
2
ATP
Figure 6.8_1
Figure 6.8_2
Figure 6.8_3
“Prep” Reaction
Pyruvate is oxidized
• 2 C acetyl-CoA
• 3rd C released as CO2
• NAD+ -> NADH
“Prep” Reaction
NAD+
NADH
+ H+
CoA
Pyruvate
Acetyl CoA
(acetyl coenzyme A)
CO2
Figure 6.8
Coenzyme A
Citric Acid Cycle
Acetyl CoA
CoA
CoA
CITRIC ACID CYCLE
2 CO2
3 NAD+
FADH2
3 NADH
FAD
+
3 H+
ATP
ADP + P
Citric Acid Cycle
• Loads e- and H onto NAD+ and FAD
• ATP by substrate-level Phos.
Citric Acid Cycle
•1 turn yields:
–
–
–
–
–
2 CO2
1 ATP,
3 NADH
1 FADH2
Regenerates starting
product
CoA
Acetyl CoA
CoA
2 carbons enter cycle
Oxaloacetate
NADH
Citrate
+ H+
NAD+
CO2 leaves cycle
CITRIC ACID CYCLE
NAD+
Malate
NADH
ADP
FADH2
+
+ H+
P
ATP
Alpha-ketoglutarate
FAD
CO2 leaves cycle
Succinate
NADH
Step
Acetyl CoA stokes the furnace.
Steps
+ H+
and
NADH, ATP, and CO2 are
generated during redox
reactions.
NAD+
Steps
and
Redox reactions generate
FADH2 and NADH.
Electron Transport
•
•
•
•
•
Coenzymes deliver electrons
Pump H+
Forms H+ gradient
H+ flows down gradient
Powers ATP formation (ATP synthase)
Figure 6.12a
Importance of Oxygen
H+
H+
H+
H+
+
.
H
H+
Protein
complex
H+
Electron
carrier
Intermembrane
space
H+
H+
ATP
synthase
Inner
mitochondrial
membrane
FADH2
Electron
flow
NADH
FAD
NAD+
+
H
Mitochondrial
matrix
1O
+ 2 H+
2 2
H+
H+
H2O
Electron Transport Chain
OXIDATIVE PHOSPHORYLATION
Figure 6.10
ADP
+
P
H+
ATP
Chemiosmosis
Summary of Energy Harvest
(per molecule of glucose)
• Glycolysis
– 2 ATP
• Citric acid and “prep” rxns
– 2 ATP
• ETC
– 32 ATP formed
FYI - Efficiency of
Aerobic Respiration
• 686 kcal of energy are released
• 7.5 kcal are conserved in each ATP
• When 36 ATP form, 270 kcal (36 X 7.5)
are captured in ATP
• Efficiency is 270 / 686 X 100 = 39 percent
• Most energy is lost as heat
Poisons
•Block the movement of electrons (cyanide,
CO)
•Block the flow of H+ through ATP synthase
(Oligomycin)
Cyanide,
carbon monoxide
Rotenone
H+
H+
H+
Oligomycin
H+
H+
H+ H+ H+
H+
ATP
Synthase
DNP
FADH2
FAD
1 O2 + 2 H+
2
NAD+
NADH
H+
H+
H+
Electron Transport Chain
Figure 6.11
H2O
ADP + P
ATP
Chemiosmosis
Anaerobic Pathways
• Less ATP
• Fermentation pathways
Fermentation Pathways
• Bacteria
– Lactobacillus (cheese)
• Animal cells
Fermentation Pathways
• Glycolysis
• 2 ATP
• Regenerate NAD+
Lactate Fermentation
• Muscle cells FAST ATP
• Lactic acid builds up
2
NAD+
2
2
NADH
NADH
2
NAD+
GLYCOLYSIS
2 ADP + 2
P
2
ATP
2 Pyruvate
Glucose
2 Lactate
Alcoholic Fermentation
• Produces ethanol
• Yeast
2
NAD+
2 NADH
2 NADH
2
NAD+
GLYCOLYSIS
2 ADP + 2 P
Glucose
Figure 6.13B
2
2
ATP
2 Pyruvate
CO2 released
2 Ethanol
Figure 6.16
Question of the Day
How does the insecticide rotenone
work? Is it safe?