1. Aerobic
Cellular
Respiration
By: Meghan Taylor

2. Agenda
 Curriculum Expectations
 Overview of cellular respiration
 Glycolysis
 Pyruvate Oxidation
 Kreb’s Cycle
 Chemiosmosis and Electron Transport
Chain
 Activity

3. Curriculum Expectations
 C2.1: use appropriate terminology related to metabolism,
including, but not limited to: energy carriers, glycolysis, Krebs
cycle, electron transport chain, ATP synthase, oxidative
phosphorylation, chemiosmosis, proton pump, photolysis,
Calvin cycle, light and dark reactions, and cyclic and
noncyclic phosphorylation
 C3.1explain the chemical changes and energy conversions
associated with the processes of aerobic and anaerobic
cellular respiration
 c3.3 use the laws of thermodynamics to explain energy
transfer in the cell during the processes of cellular respiration
and photosynthesis
 c3.4 describe, compare, and illustrate (e.g., using flow charts)
the matter and energy transformations that occur during the
processes of cellular respiration (aerobic and anaerobic)
and photosynthesis, including the roles of oxygen and
organelles such as mitochondria and chloroplasts

4. Aerobic Cellular Respiration
 Occurs in the presence of oxygen
 An exothermic reaction (∆G= -2870 kJ/mol)
 The cell only captures 34% of the available free
energy in the form of ATP
3 goals:
1. To break the bonds between the 6-C atoms of
glucose, resulting in 6 carbon dioxide molecules
2. To move hydrogen atom electrons from glucose
to oxygen , forming 6 water molecules
3. To trap as much of the free energy released in the
process as possible in the form of ATP.

5. ATP: Adenosine Triphosphate
• Contains a
nitrogenous base
(adenine), a
ribose sugar and 3
phosphate group
• High energy bond
between the 2nd
and 3rd
phosphate group
• When that bond is
broken, an
abundance of
energy is released

6. Energy Transfer
 2 ways in which available free energy is captured into the form of
ATP
1. Substrate-Level Phosphorylation
• ATP is formed directly in an enzyme-catalyzed reaction.

7. Energy Transfer
2. Oxidative Phosphorylation
• ATP is formed indirectly through a series of enzyme-
catalyzed redox reactions involving oxygen as the final
electron acceptor.
NAD+ to NADH:
 NAD+ removes 2
hydrogen atoms (2
protons, 2 electrons)
from glucose forming
NADH using a
dehydrogenase
enzyme
FAD to FADH2:
LEO the lion goes GER  FAD is reduced by 2
- Lose electrons, oxidization hydrogen atoms from
- Gain electrons, reduction glucose

8. Glucose:
 6- carbon monosaccharide
 Primary source of energy for plants and animals

9. Glycolysis
 10 step process that occurs in the cytoplasm under
anaerobic conditions
 A process that evolved in prokaryotes prior to the
emergence of organelles, notably the mitochondria
1. Glucose is
phosphorylated to G6P
(Investment phase)
2. Glucose is
rearranged to F6P
3. Glucose is
phosphorylated to F1,6-
BP (investment phase)

10. Glycolysis (cont’d) 4&5. F 1, 6-BP is split
into DHAP and G3P,
then DHAP is
converted into G3P,
resulting in two G3P
molecules
6. Two G3P are
converted to
two BPG. Hydrogen
atoms reduce NAD+
to NADH.
7. BPG is converted to
3PG. A high energy
phosphate group on
BPG phosphorylates
ADP to AT
8. 3PG is rearranged to
2PG

11. Glycolysis
9. 2PG is converted
to PEP by removal of
a water molecule
10. PEP is converted
to pyruvate. A high
energy phosphate
group on PEP
phosphorylates ADP
to ATP
Invested 2 ATP
Gained 2 NADH
4 ATP
Net: 2 NADH and 2 ATP

13. Glycolysis Links:
http://highered.mcgraw-
hill.com/sites/0072507470/student_view0/chapt
er25/animation__how_glycolysis_works.html
Youtube videos:
http://www.youtube.com/watch?v=evYmyHgj5
50
http://www.youtube.com/watch?v=EfGlznwfu9
U

14. Mitochondria
 The power house of the cell, specialized
organelles that generate ATP
 Only eukaryotic cells contain mitochondria
 Double membrane, inner membrane is highly
specialized

15. Pyruvate Oxidation
1. Carboxyl group is removed as CO2 (by pyruvate decarboxylase)
2. Pyruvate is oxidized while NAD+ is reduced
3. CoenzymeA (CoA) is attached to the acetyl group.
Gained: 1 NADH (X2 for each pyruvate)

16. Kreb’s Cycle
Gained:
1 ATP
3 NADH
1 FADH2
(X2 for each
acetyl-CoA)

17. Kreb’s Cycle Links:
 http://highered.mcgraw-
hill.com/sites/0072507470/student_view0/chapt
er25/animation__how_the_krebs_cycle_works__
quiz_1_.html
 Student Project:
 http://www.youtube.com/watch?v=aMBIs_Iw0
kE&list=PLBiiS3G1bbMpPr8SBg9tcwaTxoaVBb5W
W

18. From here..
 Bythe end of the Kreb’s cycle the original
glucose molecule has been consumed as
the carbon atoms exited as waste in the
form of CO2
 We have created 4 ATP molecules via
substrate level phosphorylation, 10 NADH
and 2 FADH2

19. Electron Transport and
Chemiosmosis
 NADH and FADH2 eventually transfer the hydrogen
atom electrons they carry to a series of proteins in the
inner mitochondrial membrane, called the ETC
 Each component is alternately reduced from the
component before it and oxidized by the component
after it.
 Electrons from NADH and FADH2 are shuttled from one
component to the next like a baton in a relay race.
 Oxygen is one of the most electronegative
components, which is needed to oxidize the last
component of the ETC

20. ETC
• Components of ETC are arranged in order of increasing
electronegativity (The ability of an atom in a molecule to attract a
shared electron pair to itself)
• Ubiquinone and cytochrome C are mobile electron carriers that
shuttle the electrons from one complex to the next.
• Many folds of the inner membrane increase surface area and allow
many copies of the ETC

21. ETC cont’d
 http://highered.mcgraw-
hill.com/sites/0072507470/student_view0/
chapter25/animation__electron_transport
_system_and_atp_synthesis__quiz_1_.html

22. ETC cont’d
• NADH passes its
electrons on to the first
protein complex, and
FADH2 transfers its
electrons to Q
• Therefore FADH2
pumps 2 protons into
the inter membrane
space while NADH
pumps 3.
• Cytosolic NADH
created in glycolysis
cannot pass through
the inner membrane
into the matrix
• Glycerol-phosphate shuttle oxidizes NADH to reduce FAD in the
matrix into FADH2 so that it can be used.

23. Chemiosmosis
 An electrochemical gradient is created with the H+ ions built up in
the inter membrane space, storing free energy.
 The inner mitochondrial membrane is impermeable to protons,
forcing them to pass through special proton channels associated
with ATP synthase
• As protons move
through the ATP
synthase
complex, the
free energy of
the gradient is
reduced
• This causes the
synthesis of ATP
from ADP and
inorganic
phosphate in the
matrix

24. What if there was no O2?
 Without oxygen, we wouldn’t be able to
free up the last protein (cytochrome
oxidase) and the chain would be
clogged with stationary electrons. Then
H+ ions would not be pumped into the
inter membrane space to create the
electrochemical gradient.

25. The Big Picture

26. How many ATP molecules?

27. ETC tools:
 Kinesthetic learners:
http://www.scienceprofonline.com/metabolism/electron-transport-chain-
classroom-activity.html

28. How many ATP did you create
if….
 Under normal conditions?
 You were in anaerobic conditions?
 Through just NADH?