3. Overview of Cellular Respiration
-Organisms obtain energy (ATP) in a process called cellular respiration.
-The equation for cellular respiration is the opposite of the equation for photosynthesis.
Memorize this equation

4. Cellular respiration can be broken into three major
parts:
Glycolysis
The Kreb’s Cycle
The electron transport chain (ETC)

5. 1. Glycolysis
-In a series of enzymatically catalyzed steps, glucose is broken down into pyruvate in the cytoplasm through the process of glycolysis.
-In addition to pyruvate, two molecules of ATP and two molecules of NADH (electron carriers) are formed for each molecule of glucose that is broken down.
*If no oxygen is present – the process stops here.
Only 2 ATP have been made. This is called
anaerobic respiration.

7. -Two molecules of pyruvate are the products of
the glucose being broken down. They move on
to the Kreb’s cycle inside the mitochondria.

8. A.K.A. The Citric Acid Cycle
2. Krebs Cycle
A.K.A. The Citric Acid Cycle
-After glycolysis, most of the energy from the glucose is still contained in the pyruvate.
-The Kreb’s Cycle is a series of reactions in which pyruvate is broken down into carbon dioxide. It
occurs in the matrix of the mitochondria.
-In the process of breaking down the pyruvate several electron carriers pick up high energy electrons for the final phase of cellular respiration.
-The net yield from the Krebs cycle is six CO2 (waste) molecules, two ATP, eight NADH, and two FADH2 (electron carriers).

11. 3. Electron Transport Chain
-The final step of cellular respiration involves using the
electrons that have been stripped (by the electron
carriers – NADH and FADH2)from the glucose to power
hydrogen ion pumps. These hydrogen ions then
provide the energy to form the ATP (32 ATP – WOW!).
The electron transport chain also occurs within the
mitochondria.
A total of 36 ATP can be made per glucose.

14. Building a
concentration
gradient. More H+
outside and less
inside. (requires
active transport).
These H+ repel each
other. This repelling
provides the energy
to add P to ADP and
make ATP.

17. What types of organisms perform cellular respiration?
Almost all living organisms!!! A few types of organisms are capable of just anaerobic respiration.
Also, chemotrophs (very rare) can use
other elements such as sulfur, iron or hydrogen for their energy. Most of these are in the domain archea