Download 2 - ATP

Cellular Respiration
Cellular Respiration
• A catabolic, exergonic, oxygen (O2) requiring
process that uses energy extracted from
macromolecules (glucose) to produce energy
(ATP) and water (H2O).
C6H12O6 + 6O2  6CO2 + 6H2O +
energy
glucose
ATP
Question:
• In what kinds organisms does cellular
respiration take place?
Plants and Animals
• Plants - Autotrophs: self-producers.
• Animals - Heterotrophs: consumers.
Mitochondria
• Organelle where cellular respiration takes place.
Outer
membrane
Inner
membrane
Inner
membrane space
Matrix
Cristae
Redox Reaction
• Transfer of one or more electrons from one
reactant to another.
• Two types:
1. Oxidation
2. Reduction
Oxidation Reaction
• The loss of electrons from a substance.
• Or the gain of oxygen.
Oxidation
C6H12O6 + 6O2 
glucose
6CO2 + 6H2O + energy
ATP
Reduction Reaction
• The gain of electrons to a substance.
• Or the loss of oxygen.
Reduction
C6H12O6 + 6O2 
glucose
6CO2 + 6H2O + energy
ATP
Breakdown of Cellular Respiration
• Four main parts (reactions).
1. Glycolysis (splitting of sugar)
a. cytosol, just outside of mitochondria.
2. Grooming Phase
a. migration from cytosol to matrix.
Breakdown of Cellular Respiration
3. Krebs Cycle (Citric Acid Cycle)
a. mitochondrial matrix
4. Electron Transport Chain (ETC) and
Oxidative Phosphorylation
a. Also called Chemiosmosis
b. inner mitochondrial membrane.
1. Glycolysis
• Occurs in the cytosol just outside of
mitochondria.
• Two phases (10 steps):
A. Energy investment phase
a. Preparatory phase (first 5 steps).
B. Energy yielding phase
a. Energy payoff phase (second 5 steps).
1. Glycolysis
A. Energy Investment Phase:
Glucose (6C)
2ATP
C-C-C-C-C-C
2 ATP - used
0 ATP - produced
0 NADH - produced
2ADP + P
Glyceraldehyde phosphate (2 - 3C)
(G3P or GAP)
C-C-C
C-C-C
1. Glycolysis
B. Energy Yielding Phase
Glyceraldehyde phosphate (2 - 3C)
(G3P or GAP)
4ADP + P
4ATP
GAP
GAP
C-C-C C-C-C
0 ATP - used
4 ATP - produced
2 NADH - produced
Pyruvate (2 - 3C)
(PYR)
C-C-C C-C-C
(PYR) (PYR)
1. Glycolysis
• Total Net Yield
2 - 3C-Pyruvate (PYR)
2 - ATP (Substrate-level Phosphorylation)
2 - NADH
Figure 9.8 The energy input and output of glycolysis
Substrate-Level Phosphorylation
• ATP is formed when an enzyme transfers a
phosphate group from a substrate to ADP.
Enzyme
Example:
PEP to PYR
Substrate
(PEP)
Product
(Pyruvate)
OC=O
C-OCH2
OC=O
C=O
CH2
P
P
P
Adenosine
ADP
P P
P
Adenosine
ATP
Fermentation
• Occurs in cytosol when “NO Oxygen” is present
(called anaerobic).
• Remember: glycolysis is part of fermentation.
• Two Types:
1. Alcohol Fermentation
2. Lactic Acid Fermentation
Alcohol Fermentation
• Plants and Fungi
C
C
C
C
C
C
glucose
2ADP
+2 P
beer and wine
2ATP
2NADH
C
C
C
Glycolysis
2 NAD+

2NADH
2 Pyruvic
acid
2 NAD+
C
C
2 Ethanol
2CO2
released
Alcohol Fermentation
• End Products: Alcohol fermentation
2 - ATP (substrate-level phosphorylation)
2 - CO2
2 - Ethanol’s
Duff
Beer
Lactic Acid Fermentation
• Animals (pain in muscle after a workout).
C
C
C
C
C
C
Glucose
2ADP
+2 P
2ATP
2NADH
C
C
C
Glycolysis
2 NAD+
2NADH
2 Pyruvic
acid
2 NAD+
C
C
C
2 Lactic
acid
Lactic Acid Fermentation
• End Products: Lactic acid fermentation
2 - ATP (substrate-level phosphorylation)
2 - Lactic Acids
2. Grooming Phase
• Occurs when Oxygen is present (aerobic).
• 2 Pyruvate (3C) molecules are transported through
the mitochondria membrane to the matrix and is
converted to 2 Acetyl CoA (2C) molecules.
Cytosol
2 CO2
C
C
C
Matrix
C-C
2 Pyruvate
2 NAD+
2NADH
2 Acetyl CoA
2. Grooming Phase
• End Products: grooming phase
2 - NADH
2 - CO2
2- Acetyl CoA (2C)
3. Krebs Cycle (Citric Acid Cycle)
• Location: mitochondrial matrix.
• Acetyl CoA (2C) bonds to Oxalacetic acid
(4C - OAA) to make Citrate (6C).
• It takes 2 turns of the krebs cycle to oxidize
1 glucose molecule.
Mitochondrial
Matrix
3. Krebs Cycle (Citric Acid Cycle)
1 Acetyl CoA (2C)
OAA (4C)
Citrate (6C)
FADH2
Krebs
Cycle
2 CO2
(one turn)
3 NAD+
FAD
3 NADH
ATP
ADP + P
3. Krebs Cycle (Citric Acid Cycle)
2 Acetyl CoA (2C)
Citrate (6C)
OAA (4C)
2 FADH2
Krebs
Cycle
4 CO2
(two turns)
6 NAD+
2 FAD
6 NADH
2 ATP
2 ADP +
P
Figure 9.11 A closer look at the Krebs cycle (Layer 4)
Figure 9.12 A summary of the Krebs cycle
3. Krebs Cycle (Citric Acid Cycle)
• Total net yield (2 turns of krebs cycle)
1. 2 - ATP (substrate-level phosphorylation)
2. 6 - NADH
3. 2 - FADH2
4. 4 - CO2
4. Electron Transport Chain (ETC) and
Oxidative Phosphorylation (Chemiosmosis)
• Location: inner mitochondrial membrane.
• Uses ETC (cytochrome proteins) and ATP
Synthase (enzyme) to make ATP.
• ETC pumps H+ (protons) across innermembrane
(lowers pH in innermembrane space).
Inner
Mitochondrial
Membrane
4. Electron Transport Chain (ETC) and
Oxidative Phosphorylation (Chemiosmosis)
• The H+ then move via diffusion (Proton Motive
Force) through ATP Synthase to make ATP.
• All NADH and FADH2 converted to ATP during
this stage of cellular respiration.
• Each NADH converts to 3 ATP.
• Each FADH2 converts to 2 ATP (enters the ETC
at a lower level than NADH).
4. Electron Transport Chain (ETC) and
Oxidative Phosphorylation (Chemiosmosis)
Outer
membrane
Inner
membrane
Inner
membrane space
Matrix
Cristae
4. ETC and Oxidative Phosphorylation
(Chemiosmosis for NADH)
higher H+
concentration
Intermembrane Space
1H+
E
2H+
3H+
T
C
NAD+
(Proton Pumping)
Matrix
ATP
Synthas
e
Inner
Mitochondrial
Membrane
O2 H O
2
2H+ + 1/2
NADH
+ H+
H+
ADP + P
H+
ATP
lower H+
concentration
4. ETC and Oxidative Phosphorylation
(Chemiosmosis for FADH2)
higher H+
concentration
Intermembrane Space
1H+
E
T
FADH2
+ H+
FAD+
(Proton Pumping)
Matrix
2H+
C
2H+ +
1/2O2
H+
ATP
Synthas
e
Inner
Mitochondrial
Membrane
H2O
ADP + P
H+
ATP
lower H+
concentration
TOTAL ATP YIELD
1. 04 ATP - substrate-level phosphorylation
2. 34 ATP - ETC & oxidative phosphorylation
18 ATP - converted from 6 NADH - Krebs cycle
38 ATP - TOTAL YIELD
ATP
Eukaryotes
(Have Membranes)
• Total ATP Yield
02 ATP - glycolysis (substrate-level phosphorylation)
04 ATP - converted from 2 NADH - glycolysis
06 ATP - converted from 2 NADH - grooming phase
02 ATP - Krebs cycle (substrate-level phosphorylation)
18 ATP - converted from 6 NADH - Krebs cycle
04 ATP - converted from 2 FADH2 - Krebs cycle
36 ATP - TOTAL
Maximum ATP Yield for Cellular
Respiration (Eukaryotes)
Glucose
Cytosol
Glycolysis
2 Acetyl CoA
2 Pyruvate
Mitochondria
Krebs
Cycle
2NADH
2 ATP
6NADH
2FADH2
(substrate-level
phosphorylation)
2NADH
ETC and Oxidative
Phosphorylation
2 ATP
(substrate-level
phosphorylation)
2ATP
4ATP 6ATP
18ATP
4ATP
36 ATP (maximum per glucose)
2ATP
Prokaryotes
(Lack Membranes)
• Total ATP Yield
02 ATP - glycolysis (substrate-level phosphorylation)
06 ATP - converted from 2 NADH - glycolysis
06 ATP - converted from 2 NADH - grooming phase
02 ATP - Krebs cycle (substrate-level phosphorylation)
04 ATP - converted from 2 FADH2 - Krebs cycle
38 ATP - TOTAL
Question:
• In addition to glucose, what other various
food molecules are use in Cellular
Respiration?
Catabolism of Various
Food Molecules
• Other organic molecules used for fuel.
1. Carbohydrates: polysaccharides
2. Fats: glycerol’s and fatty acids
3. Proteins: amino acids