- A cell is about 100 micrometers.
-Catabolic processes: are processes involving cutting or breaking up molecules to simple ones
-Anabolic processes: are processes involving building of complex molecules from simple ones.
-- Metabolism occurs inside the cell, not outside. ATP is an energy carrier. It comes from food we eat, or organic molecules stored in our body.
3 ways to generate ATP:
4-Oxidative phosphorylation through the ETC
Substrate-level phosphorylation: uses creatine phosphate. Creatine phosphate is the energy
storage in the body, while ATP is just an energy carrier.
CP + ADP Creatine + ATP
Overview of cellular energy production from glucose
Reaction Substance location Number Energy End Need for
processed of steps production product oxygen
or rxns for further
Glycolysis Glucose Cytosol 10 2 ATP 2 NADH No;
2 pyruvate anaerobic
Pyruvate 2 Pyruvate Mitochondrial 1 for 0 ATP 2 NADH Yes
oxidation matrix each 2 CO2
pyruvate 2 Acetyl
Kreb cycle 2 Acetyl Mitochondrial 8 for 2 ATP 6 NADH Yes, this
or TCA CoA matrix each 2 FADH2 oxygen is
cycle 4 Co2 derived
ETC 8 NADH Mitochondrial 32 ATP None Yes, this
4 FADH innermembrane oxygen is
Total ATP 36 ATP
-Co2 has zero energy, that’s why the body get rid of it. The energy is in the hydrogen bonds.
-Each NADH produces 3 ATP, and each FADH2 produces 2 ATP. The 2 NADH produced from
glycolysis are converted to 2 FADH2 because they lose some energy while getting transported
from the cytosol to the mitochondrial matrix.
-Notice that 34 more ATP’s where formed in the presence of oxygen. 34 ATP in aerobic
conditions Vs. 2 ATP in anaerobic conditions. - Why is the kerb cycle called a cycle?
Because the ending molecule is the same as the starting molecule (oxaloacetic acid)
- What happens to Co2 that is produced in the kerb cycle?
Each entering acetyl CoA is converted to 2 Co2 by the end of the cycle. This Co2 goes out of
mitochondria to out of the cell, into the blood, to the lungs and finally is released during
- What is the key purpose of the kreb cycle?
To produce hydrogen atoms for entry into ETC. These hydrogens are caught by the hydrogen
carrier molecules NADH & FADH2
- Does the kreb cycle produce ATP?
Yes, but indirectly. It actually produces GTP, which is then converted to ATP.
The ETC synthesizes ATP using Oxidative phosphorylation, where high energy electrons are
extracted from NADH and FADH2, and moved through protein complexes in the
innermembrane. This movement of electrons attracts H+ to move to the intermembrane space.
The end of this process creates a high H+ concentration in the intermembrane space; as we
know molecules move from high concentration to low concentration. This lead H+ to diffuse
back through the ATP synthase, which uses this diffusion (chemiosmosis) to create ATP. Finally
electrons are released through protein complex 4 to Oxygen (the final electron acceptor)
creating H2O (O2- + 4H 2 H2O).
Food releases energy twice. One time is when it is cooked; this is called uncontrolled oxidation
Food + O2 energy releases as heat. The second time is the controlled oxidation; it
happens in our body. Food + O2 ATP + energy released as heat. This heat released fr