[Respiration Notes]

Krebs Cycle

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]

[Respiration Notes]