Cellular respiration takes place in the mitochondria of cells and involves a series of metabolic pathways that break down glucose and harvest energy to produce ATP. There are four main phases: glycolysis, which occurs in the cytoplasm and produces a small amount of ATP; the link reaction and Krebs cycle, which occur in the mitochondrial matrix and further oxidize pyruvate; and the electron transport chain located in the inner mitochondrial membrane, which generates the majority of ATP through oxidative phosphorylation. The structure of the mitochondrion is adapted for this process, containing inner membrane folds called cristae that house the electron transport chain and facilitate ATP production.

1. Topic Three A: Cellular Respiration
http://images.complex.com/complex/image/upload/t_article_image/kcuapworbg0eprwvukq7.jpg

2. Essential idea: Cell respiration supplies energy for the
functions of life
http://i4.mirror.co.uk/incoming/article1231114.ece/alternates/s615/Jamaicas-
Usain-Bolt-runs-to-a-first-place-finish-in-his-mens-200m-round-1-heat.jpg
2.8 Cellular Respiration

3. Statement Guidance
2.8.U.1 Cell respiration is the controlled release of energy
from organic compounds to produce ATP.
Details of the metabolic pathways
of cell respiration are not needed
but the substrates and final waste
products should be known.
2.8.U.2 ATP from cell respiration is immediately available
as a source of energy in the cell.
2.8.U.3 Anaerobic cell respiration gives a small yield of
ATP from glucose.
2.8.U.4 Aerobic cell respiration requires oxygen and gives
a large yield of ATP from glucose.
Understandings

4. Applications and Skills
Statement Utilization
2.8 A.1 Use of anaerobic cell respiration in yeasts to
produce ethanol and carbon dioxide in
baking.
2.8 A.2 Lactate production in humans when
anaerobic respiration is used to maximize the
power of muscle contractions.
2.8 S.1 Analysis of results from experiments
involving measurement of respiration rates
in germinating seeds or invertebrates using a
respirometer.
There are many simple
respirometers which could be
used. Students are expected to
know that an alkali is used to
absorb CO2, so reductions in
volume are due to oxygen use.
Temperature should be kept
constant to avoid volume changes
due to temperature fluctuations.

5. Essential idea: Energy is converted to a useable form in cellular
respiration
https://usatftw.files.wordpress.com/2013/09/gty-1775738061.jpg?w=1024&h=681
World's strongest man lift 975 pounds
8.2 Cellular Respiration

6. Understandings
Statement Guidance
8.2 U.1 Cell respiration involves the oxidation and reduction of electron
carriers.
8.2 U.2 Phosphorylation of molecules makes them less stable.
8.2 U.3 In glycolysis, glucose is converted to pyruvate in the cytoplasm. The names of the intermediate
compounds in glycolysis is not
required.
8.2 U.4 Glycolysis gives a small net gain of ATP without the use of oxygen. The names of the intermediate
compounds in glycolysis is not
required.
8.2 U.5 In aerobic cell respiration pyruvate is decarboxylated and oxidized,
and converted into acetyl compound and attached to coenzyme A to
form acetyl coenzyme A in the link reaction.
8.2 U.6 In the Krebs cycle, the oxidation of acetyl groups is coupled to the
reduction of hydrogen carriers, liberating carbon dioxide.
The names of the intermediate
compounds in the Krebs cycle is not
required.
8.2 U.7 Energy released by oxidation reactions is carried to the cristae of
the mitochondria by reduced NAD and FAD.
8.2 U.8 Transfer of electrons between carriers in the electron transport
chain in the membrane of the cristae is coupled to proton pumping.
8.2 U.9 In chemiosmosis protons diffuse through ATP synthase to generate
ATP.
8.2 U.10 Oxygen is needed to bind with the free protons to maintain the
hydrogen gradient, resulting in the formation of water.
8.2 U.11 The structure of the mitochondrion is adapted to the function it
performs.

7. Applications and Skills
Statement Guidance
8.2 A.1 Electron tomography used to produce images of
active mitochondria.
8.2 S.1 Analysis of diagrams of the pathways of aerobic
respiration to deduce where decarboxylation
and oxidation reactions occur.
8.2 S.2 Annotation of a diagram of a mitochondrion to
indicate the adaptations to its function.

8. Cellular respiration use energy capture from the sun in a
glucose molecule and makes ATP. This process consumes
O2 during the oxidation of glucose to create CO2 and
H2O
What is the relationship between
photosynthesis and cellular respiration?
Occurs in mitochondria
2.8 U.2 ATP from cell respiration is immediately available as a source of
energy in the cell.

9.  The human body uses energy from ATP for all its activities
Energy Needs

10.  Food serves as a source of raw materials
for the cells in the body and as a source of
energy.
 Food energy is converted into a form the
cell can use (ATP) during a process called
cellular respiration.

11. • Glucose is a main energy source
used by all cells.
• Cells don’t “burn” glucose.
Instead, they gradually release
the energy from glucose and
other food compounds.
• This process begins with a
pathway called glycolysis.
• Glycolysis releases a small
amount of energy

12. CO2
H2O
Glucose
O2
ATP
ECOSYSTEM
Sunlight energy
Photosynthesis in
chloroplasts
Cellular respiration in
mitochondria
(for cellular work)
Heat energy
+ +

13. CO2
CO2
O2
O2
Bloodstream
Muscle cells carrying out
Cellular Respiration
Breathing
Glucose + O2
CO2 + H2O + ATP
Lungs
What is the relationship between
respiration and cellular respiration?

14. Respiration
• (Breathing) provides for the exchange of O2 and CO2
between an organism and its environment

15. 2.8 U.2 ATP from cell respiration is immediately available as a source of
energy in the cell.

16. 2.8 U.2 ATP from cell respiration is immediately available as a source of
energy in the cell.

17. 2.8 U.2 ATP from cell respiration is immediately available as a source of
energy in the cell.

18. 8.2 U.1 Cell respiration involves the oxidation and reduction of electron
carriers.

21. Who are the electron carries in cell respiration?
NAD+ + 2H+ + 2e- NADH + H+
reduction
oxidation
NAD+ NADH + H+
reduction
oxidation
The most common hydrogen carrier is NAD
(Nicotinamide Adenine Dinucleotide)
Use the simplified form of the equation omitting
the detail of the H+ ions and electrons:
Electron Carrier Molecules capable of accepting 1 or 2 electrons from one molecule and
donating them to another. As the electrons are transferred from one electron carrier to
another, their energy level decreases, and energy is released.

22. Who are the electron carries in cell respiration?
Another less frequently used hydrogen carrier is
FAD (Flavin Adenine Dinucleotide).
Use the simplified form of the equation omitting
the detail of the H+ ions and electrons:
FAD + 2H+ + 2e- FADH2
reduction
oxidation
FAD FADH2
oxidation
reduction

23. The Organelle of Cellular Respiration
• Cellular respiration takes place in both plant and animal cells.
• The organelle in which it takes place is the mitochondrion. –
This is also known as the ‘power-house’ of the cell.

24. Cellular Respiration
If Oxygen is present glucose is completely
oxidized in:
4 Phases
I. Glycolysis
II. Grooming Pyruvic Acid
III. Kreb Cycle
IV. Electron Transport Chain (ETC)

25. Two Mechanisms Generate ATP
 Substrate Level Phosphorylation: This mechanism generates less
amount of ATP and is an enzyme-substrate based reaction.
 Oxatative Phosphorylation: This mechanism use the mitochondrial
membrane to generate ATP in much greater amounts.
8.2 U.2 Phosphorylation of molecules makes them less stable.

26.  Glycolysis produces ATP by substrate-level
phosphorylation
Enzyme
Adenosine
Organic molecule
(substrate)
ADP ATP
P
P
P P
P
8.2 U.3 In glycolysis, glucose is converted to pyruvate in the cytoplasm.
8.2 U.4 Glycolysis gives a small net gain of ATP without the use of oxygen.
• A phosphate group is transferred from an organic
molecule to ADP.
• The phosphorylated molecule is less stable and
therefore reacts more easily in the metabolic
pathway.

27. I. First Phase – Glycolysis
•Occurs in the cytoplasm
• Breaks down of glucose into Pyruvic acid
• Produces a net gain of 2 ATP and 2 NADH
8.2 U.3 In glycolysis, glucose is converted to pyruvate in the cytoplasm.
8.2 U.4 Glycolysis gives a small net gain of ATP without the use of oxygen.

28. NAD+
NADH H+
Glucose
2 Pyruvate
ATP
2
P
2 ADP
2
2
2
2
+
+
Glycolysis
8.2 U.3 In glycolysis, glucose is converted to pyruvate in the cytoplasm.
8.2 U.4 Glycolysis gives a small net gain of ATP without the use of oxygen.

29. 8.2 U.3 In glycolysis, glucose is converted to pyruvate in the cytoplasm.
8.2 U.4 Glycolysis gives a small net gain of ATP without the use of oxygen.
Step One: Glycolysis is the splitting of glucose into pyruvate
by substrate-level phosphorylation.

30.  Glycolysis produces ATP by substrate-level
phosphorylation
8.2 U.3 In glycolysis, glucose is converted to pyruvate in the cytoplasm.
8.2 U.4 Glycolysis gives a small net gain of ATP without the use of oxygen.

31. Step One: Glycolysis is the
splitting of glucose into pyruvate
http://www.science.smith.edu/departments/Biology/Bio231/
glycolysis.html
http://highered.mheducation.com/sites/0072507470/stude
nt_view0/chapter25/animation__how_glycolysis_works.ht
ml
Use the animations to learn about the
process of glycolysis
8.2 U.1 Cell respiration involves the oxidation and reduction of
electron carriers.

32. Aerobic Respiration
Stages in the Aerobic respiration (all taking place inside the
mitochondria):
2. Link Reaction: Pyruvate is transported
into the matrix of the mitochondria and converted to Acetyl
a two carbon molecule (C2)
3. Krebs cycle: carbon fragments (C2) are
progressively decarboxylated to yield ATP and reduced
coenzymes NAD+ and FAD+
4. Electron Transport System: reduced
coenzymes NADH and FADH2 are used to generate more ATP
2.8 U.4 Aerobic cell respiration requires oxygen and gives a large yield
of ATP from glucose.

33. 8.2 U.11 The structure of the mitochondrion is adapted to the function it performs.
8.2 S.2 Annotation of a diagram of a mitochondrion to indicate the adaptations to its
function.
Label the structures:
http://commons.wikimedia.org/wiki/File:Animal_mitochondrion_diagram_en.svg

34. Label the structures: matrix
Inter-membrane space
ribosomes inner membrane
outer membrane
naked loops of DNA
cristae
http://commons.wikimedia.org/wiki/File:Animal_mitochondrion_diagram_en.svg
8.2 U.11 The structure of the mitochondrion is adapted to the function it performs.
8.2 S.2 Annotation of a diagram of a mitochondrion to indicate the adaptations to its
function.

35. 8.2 U.11 The structure of the mitochondrion is adapted to the function it performs.
8.2 S.2 Annotation of a diagram of a mitochondrion to indicate the adaptations to its
function.
Annotate the labeled structures:
matrix
Inter-membrane space
ribosomes inner membrane
outer membrane
naked loops of DNA
cristae
http://commons.wikimedia.org/wiki/File:Animal_mitochondrion_diagram_en.svg

36. 8.2 U.11 The structure of the mitochondrion is adapted to the function it performs.
8.2 S.2 Annotation of a diagram of a mitochondrion to indicate the adaptations to its
function.
Annotate the labeled structures: matrix
Inter-membrane space
ribosomes inner membrane
outer membrane
DNAA
fluid containing enzymes  for
the Krebs cycle and the link
reaction.
Small space  H+ ions
pumped into the space
quickly generate a high
concentration gradient for
chemiosmosis.
Folds in the innner
membrane 
increase surface area
available for oxidative
phosphorylation
Synthesizes
proteins, including
enzymes used in
aerobic respiration.
DNA Similar to
Prokaryotic DNA
contains the contents of the
mitochondrion  enables optimal
conditions for aerobic respiration
contains the integral
proteins that make up
the electron transport
chain and ATP synthase
 electron transport
and chemiosmosis
cristae
http://commons.wikimedia.org/wiki/File:Animal_mitochondrion_diagram_en.svg

37. 8.2 U.1 The structure of the mitochondrion is adapted to the function it performs.
8.2 S.2 Annotation of a diagram of a mitochondrion to indicate the adaptations to its
function.

38. 8.2 U.11 The structure of the mitochondrion is adapted to the function it performs.
8.2 S.2 Annotation of a diagram of a mitochondrion to indicate the adaptations to its
function.

39. 8.2 A.1 Electron tomography used to produce images of active
mitochondria.
Electron tomography is a technique for obtaining 3D structures of sub-
cellular structures using electron micrographs.
Electron tomography is improving the
understanding
of mitochondria structure and function.
Use the link to find out
more:http://www.sci.sdsu.edu/TFrey/MitoMovie.htm

40. II. Link Reaction (Grooming Pyrvic Acid)
 The conversion of pyruvate into acetyl-CoA
 Creating a Carbon Dioxide molecule (decarboxylation)
 Making it possible for the two carbon molecule to enter the
mitochondria.
8.2.U.5 In aerobic cell respiration pyruvate is decarboxylated and oxidized, and converted into
acetyl compound and attached to coenzyme A to form acetyl coenzyme A in the link reaction.

41. III. Krebs Cycle (Citric Acid Cycle)
•Occurs in the mitochondria. In the matrix (the open
space) of the mitochondria.
• Acetyl (2C) joins with Oxaloacetic Acid (4C) molecule to
produce Citric Acid (6C).
• Citric Acid goes through a series of steps to produces
energy by Substrate-level phosphorylation
•NO OXYGEN USED YET!
8.2 U.6 In the Krebs cycle, the oxidation of acetyl groups is coupled to the
reduction of hydrogen carriers, liberating carbon

42. 8.2 U.6 In the Krebs cycle, the oxidation of acetyl groups is coupled to
the reduction of hydrogen carriers, liberating carbon
Krebs cycle reduces electron carriers in
preparation for oxidative phosphorylation
(carbon is released as CO2 as a by-product)
Use the animations to learn about
Krebs cycle
http://highered.mheducation.com/olcweb/cgi/pluginp
op.cgi?it=swf::525::530::/sites/dl/free/0072464631/2
91136/krebsCycle.swf::krebsCycle.swf
http://www.wiley.com/college/pratt/0471393878/st
udent/animations/citric_acid_cycle/index.html
http://www.wiley.com/legacy/college/boyer/04
70003790/animations/tca/tca.htm
http://faculty.nl.edu/jste/aerobic_respir
ation.htm#Citric%20acid%20%28CA%
29%20cycle

43. For each turn of the cycle :
2 Cycles Totals:
• 2-ATP
• 6 NADH
• 2 FADH2
• 4 CO2
(byproduct)
• Two CO2 molecules are released
• energy yield is 1 ATP, 1 FADH2 and 3 NADH
8.2 U.6 In the Krebs cycle, the oxidation of acetyl groups is coupled
to the reduction of hydrogen carriers, liberating carbon

44. 8.2 S.1 Analysis of diagrams of the pathways of aerobic respiration to
deduce where decarboxylation and oxidation reactions occur.
1. Indicate two places where
decarboxylation occurs. (1)
2. Explain why the given places
where selected. (1)

45. 1. Indicate two places where
decarboxylation occurs. (1)
2. Explain why the given places
where selected. (1)
decarboxylation
decarboxylation
decarboxylation
The molecule reduces the number
of carbon atoms it contains in
each place, therefore each
reaction must be a
decarboxylation.
8.2 S.1 Analysis of diagrams of the pathways of aerobic respiration to
deduce where decarboxylation and oxidation reactions occur.

46. IV. Electron Transport Chain (Final Step Uses Oxygen)
 Uses the energy stored in NADH and FADH2 to make
ATP
• Each NADH = 3 ATP
• Each FADH2 = 2 ATP
• Produces H2O as a byproduct
•32-34 ATP – Oxidative phosphorylation
8.2 U.6 In the Krebs cycle, the oxidation of acetyl groups is coupled
to the reduction of hydrogen carriers, liberating carbon

47. Oxidative phosphorylation
• Electrons from NADH and FADH2
Travel down the electron transport chain to
oxygen, which picks up H+ to form H2O
• Energy released by the reactions
is used to pump H+ into the space between the
mitochondrial membranes (against the
concentration gradient)
8.2 U.6 In the Krebs cycle, the oxidation of acetyl groups is coupled
to the reduction of hydrogen carriers, liberating carbon

48.  In chemiosmosis, the H+ diffuses back through the
inner membrane through ATP synthase complexes
 Driving the synthesis of ATP
Intermembrane
space
Inner
mitochondrial
membrane
Mitochondrial
matrix
Protein
complex
Electron
flow
Electron
carrier
NADH NAD+
FADH2 FAD
H2O
ATP
ADP
ATP
synthase
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
+ P
O2
Electron Transport Chain Chemiosmosis
.
OXIDATIVE PHOSPHORYLATION
+2
1
2
8.2 U.8 Transfer of electrons between carriers in the electron
transport chain in the membrane of the cristae is coupled to proton
pumping.

49. 8.2 U.9 In chemiosmosis protons diffuse through ATP synthase to
generate ATP.

50. 8.2 U.9 In chemiosmosis protons diffuse through ATP synthase to
generate ATP.

51. 8.2 U.9 In chemiosmosis protons diffuse through ATP synthase to
generate ATP.

52. 8.2 U.9 In chemiosmosis protons diffuse through ATP synthase to
generate ATP.

53. 8.2 U.9 In chemiosmosis protons diffuse through ATP synthase to
generate ATP.

54. 8.2 U.10 Oxygen is needed to bind with the free protons to maintain the
hydrogen gradient, resulting in the formation of water.

55. A summary of oxidative phosphorylation (8.2.U8 – 8.2.U10)
http://commons.wikimedia.org/wiki/File:2508_The_Electron_Transport_Chai
http://faculty.nl.edu/jste/electron_transport_system.htm
http://highered.mheducation.com/olcweb/cgi/pluginpop.cgi
?it=swf::535::535::/sites/dl/free/0072437316/120071/bio11
.swf::Electron%20Transport%20System%20and%20ATP
%20Synthesis
http://www.wiley.com/legacy/college/boyer/0470003
790/animations/electron_transport/electron_transpor
t.htm
Use the animations to learn to check your
understanding of oxidative
phosphorylation.

56. Paradigm shift
• A dramatic change in the thinking of the
scientific community, a change from one
scientific paradigm to another

57. After many years the theory was accepted. Peter Mitchell
received the Nobel Prize for Chemistry in 1978
Nature of Science: Paradigm shift—the chemiosmotic theory led to a paradigm
shift in the field of bioenergetics. (2.3)
It takes time for scientists working in a field to accept
paradigm shifts, even when there is strong evidence.
In 1961 Peter Mitchell proposed the chemiosmotic theory.
His ideas explained how synthesis is coupled to
electron transport and proton movement.
His ideas were very different to previous explanations.
http://biologyjunction.com/chemiosmotic_theory.htm
http://www.nobelprize.org/nobel_prizes/chemistry/la
ureates/1978/press.html
Find out more:

58. • 2 ATP – Glycolysis (Anaerobic)
• 2 ATP – Citric Acid/Kreb’s cycle
• 32-34 ATP – Oxidative phosphorylation
• 36-38 Total – Cellular Respiration
TOTALS (per 1 Glucose molecule )
2.8 U.4 Aerobic cell respiration requires oxygen and gives a large
yield of ATP from glucose.

59. Glycolysi
s
Link
Reactio
n
Kreb
Cycle
ETC Total Produced
Molecules
CO2 0 2 4 6
ATP 2 0 2 32 36
NADH 2 2 6 10
FADH2 0 0 2

63. 3. The diagram shows the three stages of glycolysis.
Which processes are indicated by I, II and III?
I II III
A Lysis Phosphorylation Oxidation and
ATP formation
B Oxidation and
ATP formation
Phosphorylation Lysis
C Phosphorylation Lysis Oxidation and
ATP formation
D Phosphorylation Oxidation and
ATP formation
Lysis
8.2 S.1 Analysis of diagrams of the pathways of aerobic respiration to
deduce where decarboxylation and oxidation reactions occur.

64. 3. The diagram shows the three stages of glycolysis.
Which processes are indicated by I, II and III?
I II III
A Lysis Phosphorylation Oxidation and ATP
formation
B Oxidation and
ATP formation
Phosphorylation Lysis
C Phosphorylation Lysis Oxidation and ATP
formation
D Phosphorylation Oxidation and
ATP formation
Lysis
8.2 S.1 Analysis of diagrams of the pathways of aerobic respiration to
deduce where decarboxylation and oxidation reactions occur.

69. If no oxygen is present or the cell does not contain
mitochondria:
•Fermentation is an anaerobic alternative to cellular
respiration
•Cell can use glycolysis alone to produce small
amounts of ATP (without the production of
additional NADH (making up to 3 ATP’s or FADH2
making up to 2 ATP’s
• 2 types – I. Lactic Acid Fermentation
II. Alcohol Fermentation
Anaerobic Respiration
2.8 U.3 Anaerobic cell respiration gives a small yield of ATP
from glucose

70. I. lactic acid fermentation
• The two ATP’s created in Glycolysis are the only energy yield
in lactic acid fermentation
• (muscles and bacteria) NADH is oxidized to NAD+ as
pyruvate is reduced to lactate (lactic acid)
• 2 Lactate
• NAD+
• NADH • NADH • NAD+
• 2 • 2 • 2
• 2
• 2 • ATP
• 2 ADP + 2
• 2 Pyruvate
• GLYCOLYSIS
• P
• Glucose
• The buildup of lactic acid causes a painful, burning
sensation in your muscles
2.8 U.3 Anaerobic cell respiration gives a small yield of ATP
from glucose

71. Oxygen Debt the amount of
oxygen needed to oxidize
lactic acid to carbon dioxide
and water. The existence of
an oxygen debt explains why
we continue to breathe
deeply and quickly for a
while after exercise

72. • During high-intensity exercises,
blood flow to your muscles is
reduced; causing a reduction in
oxygen delivered to the muscles.
• In the absence of oxygen, muscle
cells use glycolysis to produce ATP.
Glycolysis generates ATP much
faster than oxidative phosphorylation.
• Because glycolysis generates ATP
much faster than oxidative
phosphorylation, some muscles will
resort to glycolysis even in the
presence of oxygen to meet their
energy needs at a faster rate.
• The major consequence of glycolysis
is the production of lactic acid which
accumulates inside of your muscles
to cause
• soreness and fatigue.
http://biology-forums.com/index.php?topic=51887.0
2.8 A.2 Lactate production in humans when anaerobic respiration is
used to maximize the power of muscle contractions.

73. http://philschatz.com/biology-concepts-
2.8 U.3 Anaerobic cell respiration gives a small yield of ATP
from glucose

74. II. alcohol fermentation
(yeast) NADH is oxidized to NAD+ while converting
pyruvate to CO2 and ethanol
NAD+
NADH NADH NAD+
2 2 2 2
GLYCOLYSIS
2 ADP + 2 P ATP
Glucose 2 Pyruvate
released
CO2
2 Ethanol
2
2
Figure 6.13B
2.8 U.3 Anaerobic cell respiration gives a small yield of ATP
from glucose

75. 1. Carbon dioxide and the baking
industry
Yeast is used in baking bread. It is
mixed into dough before baking. The
yeast uses up all the O2 and then
produces ethanol and CO2. The CO2
forms bubbles making the dough rise.
2. Ethanol and the brewing industry
Yeast is cultured in a liquid containing
sugar and other nutrients without O2
available. This causes the yeast to use
anaerobic respiration for metabolic
activities, resulting in alcohol.
2.8 A.1 Use of anaerobic cell respiration in yeasts to produce ethanol
and carbon dioxide in baking.

79. Aerobic Anaerobic
Glucose (and other hexose sugars)
used in both types of respiration
Lipids and amino acids (if in
excess) can also be used
Only Glucose is used
Oxygen in No Oxygen Required
36 ATP’s Produced 2 ATP produced
Pyruvate is an intermediate compound in both types of respiration
Animals/Plants Yeast Animals/Plants
Carbon dioxide produced CO2 /C2H5OH C3H6O3
Water produced No Water No Water

80. 2.8 S.1 Analysis of results from experiments involving measurement of
respiration rates in germinating seeds or invertebrates using a
respirometer.
Cellular Respiration Lab Walkthrough

81. Bibliography /
Acknowledgments