a) Krebs cycle ccurs in matrix of mitochondria.
b) Only occurs if O2 present.
c) Link Reaction: Pyruvate moves into matrix & loses 1 carbon as 1 CO2. 1 more NADH is made.
d) The remaining 2C molecule enters the Krebs Cycle.
In several steps,
e) energy & hydrogens are removed from the 2 carbons and changed to more NADH & FADH2. These migrate to Electron Transport.
f) 1 more ATP is made. The cell can use this.
g) each remaining carbon is removed as CO2 & released to air.
The diagram below is a very simple outline of the Krebs Cycle showing the removal of CO2, and the making of 3 NADH, 1FADH2, and 1 ATP. Its purpose is to visualize in simple form, what occurs during the Krebs Cycle. The locations where molecules are removed are not necessarily always accurate.
[More Complex Diagram of Krebs Cycle]
Summary of One Turn of the Krebs Cycle
|1. 2 Carbon molecule enters the cycle & joins a 4C molecule.|
|2. In a series of steps, the remaining H and high energy electrons are removed from the 2 C.|
|3. Three NAD+ are converted into 3 NADH & 3H+.|
|4. One FAD is converted into 1 FADH2.|
|5. One ATP is made.|
|6. Two CO2 are released.|
|7. At the end of the cycle, nothing remains of the original glucose molecule.|
[Glycolysis] [Electron Transport]