1) Cellular respiration uses oxygen and food to produce energy in the form of ATP through a series of chemical reactions. 2) There are two types of cellular respiration: aerobic respiration which uses oxygen to produce 38 ATP and anaerobic respiration which produces only 2 ATP without oxygen. 3) Aerobic respiration involves three main stages - glycolysis, the Krebs cycle in the mitochondria, and the electron transport chain - to fully break down glucose and produce large amounts of ATP through chemiosmosis.

1. Cellular Respiration

2. How cells use food and oxygen
to make energy in the form of
ATP and do work.

3. Types of Cellular Respiration
• Aerobic Cellular Respiration- Cells make
ATP using Oxygen in mitochondria
• Anaerobic Cellular Respiration- Cells
make ATP without using Oxygen in the
cytoplasm of the cell. Also referred to as
fermentation.

4. Big Picture
Both are catabolic reactions that produce
energy in the form of ATP.

5. Aerobic cellular respiration is the
chemical (metabolic) reaction that uses
O2 and produces CO2 so it is the reason
why we need to breathe.

6. Equation for Aerobic Cellular
Respiration
Glucose + O2 CO2 + H2O + ATP

7. 3 main chemical reactions in
aerobic cellular respiration
Glycolysis
Krebs Cycle
Electron Transport System

8. 1. Glycolysis
• Catabolic reaction that breaks glucose into
2 molecules of pyruvic acid or pyruvate.
• Occurs in the cytoplasm of the cell
• Does not use O2 (it is part of cellular
respiration but it is also the first step in the
fermentation process as well)

9. Glucose----------> 2 molecules pyruvate
+ 2 ATP
+ 2 NADH (Electron Carrier)

10. Glycolysis produces a little bit of energy in
the form of ATP and NADH.

11. What are Electron Carriers?
NADH and FADH2 are Electron Taxi Cabs
They pick electrons up and transport them to
The Grand Central Station for Electrons- the ets

12. Oxidation- removes electrons
Reduction adds electrons

13. 2. Krebs Cycle
• Complex sequence of reactions that occur
in the mitochondrial matrix.
• Reactions complete the breakdown of the
original glucose molecule by acting on pyruvic
acid

14. We call it a cycle
because it is
continuously running
and it is always
recycling the starting
molecule.

15. Major Impact of the Krebs Cycle
•Completes the break down of glucose
•Makes a lot of electron carriers (NADH,
FADH2)
•Produces the majority of CO2 that must be
eliminated from the system

16. Matrix
Cristae
Sometimes called the matrix reactions because
of where they occur in the mitochondria

17. How?
Pyruvic acid enters the mitochondria from
the cell cytoplasm and then is converted into
another molecule called Acetyl Co-A.

19. How much energy is made during
the Krebs Cycle ?
1. 2- ATP
2. 8 NADH
3. 2 FADH2
4. 6 CO2 (We get rid of it by
exhaling)

21. 3. Electron Transport System
The electron transport system is a series
of molecules embedded in the cristae of
the mitochondria that accept and
transfer electrons. (Oxidation-Reduction)

22. The ETS uses the shuttling of electrons
donated by NADH and FADH2 to make a lot
of ATP.

23. Oxidation- molecule loses an electron
Reduction- molecule gains an electron

26. The ETS proteins take the electrons
from NADH and FADH2 and move
them down to oxygen.
NADH NAD+
FADH2 FADH

27. At each transfer (oxidation-reduction)
some energy is lost.
This creates energy that is used to take Pi
(inorganic PO4) and add it to ADP to
make ATP in a process called oxidative
phosphorylation.

29. Phosphorylation
Adding phosphate to another molecule
Oxidative Phosphorylation
Adding phosphate to another molecule in the
electron transport system in the presence of
Oxygen

30. Substrate level phosphorylation
Any other phosphorylation in the cell

31. Chemiosmosis
Oxidative phosphorylation of ADP to make ATP
occurs through Chemiosmosis.
As electrons are being transferred through the ets
the energy is used to pump Hydrogen ions across
one side of the membrane.
This builds up a higher concentration on one side
than the other. Like a Hydrogen ion dam.

32. Because substances have
a tendency to move
from a higher
concentration to a lower
concentration, the
hydrogen ion dam can
be used
to do work.

33. The only way for the
Hydrogen ions to
move down their
concentration
gradient is back
through the
membrane through
the enzyme ATP
Synthase.

34. The Hydrogen ion
turns on the
enzyme allowing it
to phosphorylate
ADP and make an
ATP molecule

35. The electron transport system uses all of the
electron carriers to produce about 34
molecules of ATP.
This system uses oxygen as its final electron
acceptor.

37. Anaerobic Cellular Respiration
(Fermentation)
There are lots of different kinds of fermenations
They are usually named after their end-product
6. Ethanol and CO2- alcohol
8. Lactic acid- yogurt- also occurs in muscles

38. Glycolysis always occurs first with glucose
being converted into 2 molecules of pyruvate.
Ethanol Fermentation
Pyruvate Ethanol + CO2

40. Lactic Acid Fermentation
Pyruvate Lactic Acid
This can occur by adding microbes to milk to
make cheese or yogurt but also occurs in the
muscles when O2 is not being delivered fast
enough to run aerobic cellular respiration.

42. Glycolysis and fermentation only
produces 2 ATP per glucose molecule
so it is a very inefficient way to make ATP
for cells.
Once we add the mitochondria in and use
O2 to make ATP we can get as many as
36-38 ATP’s being formed per glucose
molecule