How is ATP generated? (2 ways)
- substrate-level phosphorylation
- oxidative phosphorylation
Substrate-level phosphorylation
An organic molecule transfers a phosphate group directly to ADP to make ATP. Includes a hydrolysis reaction to yield a phosphate group, and a reaction to couple that phosphate group to ADP.
Only produces a small amount of fuel.
Oxidative phosphorylation
- Chemical energy from org molecule transferred to electron carriers (electron transport chain)
- Energy gathers as electron moves through ETC, releasing to produce ATP
Two electron carriers:
NAD and FAD
Oxidized form of NAD and FAD
NAD+ and FAD
Reduced form of NAD and FAD
NADH and FADH2
Reduced molecules experience an increase in what type of bond?
C-H
What are the four stages of cellular respiration?
- Glycolysis
- Pyruvate Oxidation
- Citric acid cycle
- Oxidative phosphorylation
What happens during glycolysis?
Glucose partially broken down to produce pyruvate.
Energy transferred to ATP and reduced e- carriers.
What happens in Pyruvate Oxidation?
Pyruvate oxidized to make acetyl-CoA.
This produces reduced e- carriers and CO2 is released.
What happens during the citric acid cycle?
Acetyl-CoA enters.
Acetyl group oxidized to CO2.
Energy is transferred to ATP and reduced electron carriers.
What happens during oxidative phosphorylation?
The reduced e- carriers generation from stages 1, 2, and 3 donate e- to the respiratory electron transport chain. LOTS of ATP produced!
What are the three phases of glycolysis?
- Preparatory phase (uses 2 ATP)
- Cleavage phase
- Payoff phase (produces 4 ATP + 2 NADH)
Phases of Glycolysis
- Addition of two phosphate groups. Requires 2 ATP = phosphorylated glucose. This step destabilizes and traps the molecule.
- Cleavage. Split from 6C molecule to two 3 C molecules. [G3P]
- Payoff. ATP and NADH produced as well as 2 molecules pyruvate.
What are the products of glycolysis?
2 pyruvate
4 ATP (but 2 consumed)
2 NADH
What are the reactants of glycolysis?
Single molecule of glucose.
Pyruvate Oxidation
Pyruvate oxidized to acetyl-CoA, enters citric acid cycle.
Intermembrane space
Space between the inner and outer membranes.
Mitochondrial Matrix
Space enclosed by the inner membrane.
How is pyruvate oxidation initiated?
Pyruvate enters the mitochondrial matrix, converted to acetyl-CoA.
How is pyruvate converted to acetyl-CoA?
Pyruvate is oxidized, forms CO2.
Electrons go to NAD+, turns into NADH.
Remaining part of pyruvate (COCH3) transferred to CoA.
What are the products of pyruvate oxidation?
1 CO2
1 NADH
PER pyruvate. 2 enter so products x2
What substrate enters the citric acid cycle?
Acetyl-CoA
Summarize the citric acid cycle
Acetyl group of acetyl-CoA is oxidized to CO2. Chemical energy is transferred to ATP and to the reduced e- carriers NADH and FADH2.
**Supplies electrons to the electron transport chain*
