Cellular Respiration 9.2 The Process of Cellular Respiration.
Overview of Cellular Respiration Copy the Slides with the Smiley Face.
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Transcript of Overview of Cellular Respiration Copy the Slides with the Smiley Face.
Overview of Cellular Respiration
Copy the Slides with the Smiley Face
ATP Supplies Energy for Cellular Function
• What activities require ATP?
• Where does this energy come from?– Food and O2 are needed to make ATP.
• How does it work?
Figure 9.1
The big picture
• Photosynthesis light
6 CO2 + 12 H20 -------> C6H12O6 + 6 H20+6O2
• Cellular Respiration C6H12O6 + 6 H20+6O2 -----> 6 CO2 + 12 H20 +energy
The big picture
• Photosynthesis
6 CO2 + 12 H20 ---> C6H12O6 + 6 H20+6O2
• Cellular Respiration
C6H12O6 + 6 H20+6O2 -----> 6 CO2 + 12 H20
Figure 9.2
Lightenergy
ECOSYSTEM
Photosynthesisin chloroplasts
Cellular respirationin mitochondria
CO2 H2O O2
Organicmolecules
ATP powersmost cellular workATP
Heatenergy
Catabolic Pathways and Production of ATP
• The breakdown of organic molecules is exergonic
• Fermentation is a partial degradation of sugars that occurs without O2
• Aerobic respiration consumes organic molecules and O2 and yields ATP
• Anaerobic respiration is similar to aerobic respiration but consumes compounds other than O2
© 2011 Pearson Education, Inc.
Energy Procurement
• Chemical bonds are broken in small steps that maximize the energy that is made available to the cell from food.
• Energetic Electrons are not haphazardly thrown throughout the cell...
NADH and FADH2 ARE ELECTRON SHUTTLES
• NAD is reduced to NADH, FAD is reduced to FADH2
• These high energy e-s are carried to inner mitochondrial membrane to make ATP.
• Electron cascade-- e-s then pass down a complex of carriers on a membrane, releasing packets of energy in small increments.
• We talked about enzyme complexes (ch 8), this uses several. (see page 175, electron transport chain, ETC)
Figure 9.5
(a) Uncontrolled reaction (b) Cellular respiration
Explosiverelease of
heat and lightenergy
Controlledrelease ofenergy for
synthesis ofATP
Fre
e en
erg
y, G
Fre
e en
erg
y, G
H2 1/2 O22 H 1/2 O2
1/2 O2
H2O H2O
2 H+ 2 e
2 e
2 H+
ATP
ATP
ATP
Electro
n tran
spo
rt
chain
(from food via NADH)
Stepwise Energy Harvest via NAD+ and the Electron Transport Chain• 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
• As an electron acceptor, NAD+ functions as an oxidizing agent during cellular respiration
• Each NADH (the reduced form of NAD+) represents stored energy that is tapped to synthesize ATP
© 2011 Pearson Education, Inc.
Figure 9.4
Nicotinamide(oxidized form)
NAD
(from food)
Dehydrogenase
Reduction of NAD
Oxidation of NADH
Nicotinamide(reduced form)
NADH
This is NAD+
Does this remindyou of anything?
Oxidation of Organic Fuel Molecules During Cellular Respiration
• During cellular respiration, the fuel (such as glucose) is oxidized, and O2 is reduced
© 2011 Pearson Education, Inc.
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)
© 2011 Pearson Education, Inc.
2 ways to make ATP• Oxidative Phosphorylation-Proton gradient across
membrane stores potential energy. – This occurs alongside ETC– - Chemiosmosis-Protons pass thru ATP synthase to make
ATP
• Substrate level phosphorylation– Simpler, not membrane bound– Phosphate transferred from a substrate to ADP, forms ATP– GYCOLYSIS AND KREB’S
Aerobic Respiration occurs in four stages1) Glycolysis-
1) Glucose to pyruvate, in cytoplasm
2) Pyruvate Oxidation1) Pyruvate ---> Acetyl CoA, in Mitochondrial
Intermembrane Space
3) Citric Acid Cycle (same as Kreb’s Cycle)1) Acetyl CoA---> CO2, ATP, NADH, FADH2 in
Mitochondrial Matrix
4) Electron Transport Chain1) NADH, FADH2 ----> High Levels of ATP and water
Inner mitochondrial membrane
Figure 9.6-3
Electronscarried
via NADH
Electrons carriedvia NADH and
FADH2
Citricacidcycle
Pyruvateoxidation
Acetyl CoA
Glycolysis
Glucose Pyruvate
Oxidativephosphorylation:
electron transportand
chemiosmosis
CYTOSOL MITOCHONDRION
ATP ATP ATP
Substrate-levelphosphorylation
Substrate-levelphosphorylation
Oxidative phosphorylation
Where processes take place:
Figure 9.9-4
Glycolysis: Energy Investment Phase
ATP ATPGlucose Glucose 6-phosphate Fructose 6-phosphate Fructose 1,6-bisphosphate
Dihydroxyacetonephosphate
Glyceraldehyde3-phosphate
Tostep 6
ADP ADP
Hexokinase Phosphogluco-isomerase
Phospho-fructokinase
Aldolase
Isomerase
12 3 4
5
Figure 9.9-9
Glycolysis: Energy Payoff Phase
2 ATP 2 ATP2 NADH
2 NAD + 2 H
2 P i
2 ADP
1,3-Bisphospho-glycerate
3-Phospho-glycerate
2-Phospho-glycerate
Phosphoenol-pyruvate (PEP)
Pyruvate
2 ADP2 2 2
2 H2O
Phospho-glycerokinase
Phospho-glyceromutase
Enolase Pyruvatekinase
67 8
910
Triosephosphate
dehydrogenase
Figure 9.12-8
NADH1
Acetyl CoA
CitrateIsocitrate
-Ketoglutarate
SuccinylCoA
Succinate
Fumarate
Malate
Citricacidcycle
NAD
NADH
NADH
FADH2
ATP
+ H
+ H
+ H
NAD
NAD
H2O
H2O
ADP
GTP GDP
P i
FAD
3
2
4
5
6
7
8
CoA-SH
CO2
CoA-SH
CoA-SH
CO2
Oxaloacetate
Citric Acid Cycle(Kreb’s Cycle)
Figure 9.14
INTERMEMBRANE SPACE
Rotor
StatorH
Internalrod
Catalyticknob
ADP+P i ATP
MITOCHONDRIAL MATRIX
What are we looking at? _____________
Figure 9.15
Proteincomplexof electroncarriers
(carrying electronsfrom food)
Electron transport chain
Oxidative phosphorylation
Chemiosmosis
ATPsynth-ase
I
II
III
IVQ
Cyt c
FADFADH2
NADH ADP P i
NAD
H
2 H + 1/2O2
H
HH
21
H
H2O
ATP
Figure 9.19
CarbohydratesProteins
Fattyacids
Aminoacids
Sugars
Fats
Glycerol
Glycolysis
Glucose
Glyceraldehyde 3- P
NH3 Pyruvate
Acetyl CoA
Citricacidcycle
Oxidativephosphorylation
Figure 9.20
Phosphofructokinase
Glucose
GlycolysisAMP
Stimulates
Fructose 6-phosphate
Fructose 1,6-bisphosphate
Pyruvate
Inhibits Inhibits
ATP Citrate
Citricacidcycle
Oxidativephosphorylation
Acetyl CoA
NEGATIVE FEEDBACKEXAMPLE
Anaerobic Respiration
• ATP is made in glycolysis only
• NADH needs to be recycled
• Ethanol (Alcohol) fermentation– Acetaldehyde intermediate
– CO2, ATP and ethanol are products. How do products benefit humans?
• Lactic Acid fermentation– Only lactate and ATP produced. What is the benefit to
humans?
Anaerobic Respiration
• See animation
Remember: Protein Kinase
• A protein kinase or kinase is an enzyme that adds a phosphate group from ATP to a target protein.
• HARVARD MITOCHONDRIA ANIMATION
Effect of poisons and toxins
• Cyanide- competive inhibitor of cytochrome C oxidase. Blocks ATP production.
• Rotenone (rat poison and insecticide)- competive inhibitor of NADH producing enzyme, which inhibits ATP production
• Carbon monoxide (CO) – binds with Hb 300 X more efficiently than O2. No oxygen, no final electron acceptor
What you will be tested onin Respiration
• These notes
• Major Products and Reactants of each stage
• Meaning what goes in, and what comes out. You need to know number of ATP derived from each stage.
• Fill in the blank items on handouts.