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Chapter 15: Cellular Respiration
Chapter outlines:
i.
ii.
iii.
iv.
v.
vi.
vii.
Structure of ATP & its role in living organisms
Process of ATP production: substrate level &
oxidative phosphorylation
Describe glycolysis, link reaction & Krebs cycle
Describe ETC and chemiosmosis
Explain how active cells derive 38 ATPs
Explain complete oxidation of 1 molecule of glucose
Describe alcoholic and lactate fermentation
Overview of Cellular Respiration
Redox & the role of NAD as electron carrier
Substrate Level Phosphorylation &
Oxidative Phosphorylation
Glycolysis
Stages in Glycolysis
Glucose
ATP
ADP
Glucose-6phosphate
Fructose-6phosphate
ATP
ADP
Fructose-1,6bisphosphate
Dihydroxyacetonephosphate
Glyceraldehyde-3phosphate
Stages in Glycolysis
Glyceraldehyde-3phosphate
NADH + H+
1,3 bisphosphoglycerate
ATP
3 phosphoglycerate
2-phosphoglycerate
Phosphoenolpyruvate
ATP
Pyruvate
Review of glycolysis
1
2
3
4
5
6
7
8
9
10
Review of glycolysis
Process
1
Input
Output
1. phosphorylation
glucose
ATP
Glucose-6-phosphate
ADP
2. isomerisation
Glucose-6-phosphate
Fructose-6-phosphate
3. phosphorylation
Fructose-6-phosphate
ATP
Fructose-1, 6-phosphate
ADP
4
4. Cleavage / lysis
Fructose-1, 6-phosphate
Dihydroxyacetone phosphate &
Glyceraldehyde-3-phosphate
5
5. Isomerization
Dihydroxyacetone phosphate &
Glyceraldehyde-3-phosphate
Glyceraldehyde-3-phosphate
6. Oxidation and
phosphorylation
Glyceraldehyde-3-phosphate
2NAD+
1, 3-bisphosphoglycerate
2NADH + H+
7. Substrate-level
phosphorylation
1,3-bisphospho-lycerate
2ADP
3-phosphoglycerate
2ATP
8. Isomerization
3-phosphoglycerate
2-phosphoglycerate
9. Dehydration
2-phosphoglycerate
Phosphoenolpyruvate
10. Substrate-level
phosphorylation
phosphoenolpyruvate
2ADP
pyruvate
2ATP
2
3
6
7
8
9
10
TOTAL:
2ATP, 2NAD+
4ATP, 2NADH + H+
PSPM 2008/09
Chapter 15: Cellular Respiration
2. FIGURE 2 shows some of the steps involved in cellular respiration
in muscle tissues.
(a) Name the process which involves the above steps.
_________________________________
[1m]
(b) In which TWO steps are ATPS being used? Why is ATP used?
__________________________________________
__________________________________________
__________________________________________ [3m]
(c) Name the enzymes involved in steps P and Q.
Step P : _________________________
Step Q : _________________________
[2m]
(d) In which step is NADH produced? State the function of NADH.
__________________________________________
__________________________________________ [2m]
(e) How many molecules of NADH and pyruvate are produced
from one molecule of 1.3-bisphosphoglyerate?
___________________________________________ [2m]
Link Reaction
Carbon
dioxide
CO2
Pyruvate
NAD+
Coenzyme A
NADH
Acetyl coenzyme A
Link Reaction
CO2
Pyruvate
Acetyl- CoA
NAD+
Process
NADH + H+
Input
Output
Decarboxylation
3C pyruvate
2C compound
Oxidation
2C compound
reduction
NAD+
2C acetate (unstable)
NADH + H+ (electron carrier)
Attachment of Coenzyme
Co-enzyme
Acetyl-CoA
Acetyl CoA releases CoA
Krebs cycle
Citrate is converted
to isocitrate
form acetyl
group
2
Acetyl group
combine to
oxaloacetate
forming citrate
1
isocitrate
citrate
3
NADH + H+
oxaloacetate
Malate is oxidized by
reducing NAD+ to
NADH + H+
8
Regeneration
of oxaloacetate
Isocitrate undergoes oxidation
and decarboxylation to form
α-ketoglutarate
Carbon dioxide formed.
Hydrogen transferred from
NAD+ to NADH + H+
α-ketoglutarate
Krebs
cycle
NADH + H+
4
NADH + H+
Malate
Fumarate
Fumarate is converted
to malate by addition of
water.
Succinyl-CoA
Succinate
7
5
GDP
GDP
FADH2
Succinate oxidized to form fumarate.
Hydrogen transferred to FAD to form FADH2
6
α-ketoglutarate
undergoes oxidation and
decarboxylation and
attached to an unstable
bond to form succinylCoA.
Carbon dioxide formed.
Hydrogen transferred
from NAD+ to NADH + H+
ADP
ATP
CoA is displaced by a phosphate group, GDP
phosphorylated to GTP and then ADP form
ATP by substrate-level phosphorylation
Succinyl-CoA converted to succinate
Acetyl CoA release CoA
Krebs cycle
Citrate is converted
to isocitrate
form acetyl
group
2
1
isocitrate
citrate
3
NAD+
NADH + H+
oxaloacetate
α-ketoglutarate
8
Krebs
cycle
NADH + H+
NAD+
4
Malate
Succinyl-CoA
NAD+
Fumarate
Succinate
NADH + H+
5
7
GDP
FAD
ADP
6
FADH2
ATP
GDP
Acetyl CoA release CoA
form acetyl
group
2
1
isocitrate
NAD+
citrate
3
NADH + H+
oxaloacetate
NADH + H+
8
Krebs cycle
NAD+
α-ketoglutarate
Malate
4
FAD
7
Fumarate
Succinyl-CoA
FADH2
5
6
Succinate
Acetyl CoA release CoA
form acetyl
group
2
NAD+
isocitrate
Acetyl group
combine to
oxaloacetate
forming citrate
1
3
citrate
oxaloacetate
NADH + H+
8
α-ketoglutarate
Krebs cycle
NAD+
Malate
4
FAD
7
NADH + H+
Fumarate
Succinyl-CoA
FADH2
6
5
Succinate
Acetyl coenzyme A
Coenzyme A
Citrate
Oxaloacetate
NADH
NAD+
NAD+
CITRIC
ACID
CYCLE
H2O
NADH
CO2
FADH2
5-carbon compound
FAD
NADH
GTP
GDP
4-carbon compound
ADP
ATP
CO2
Chapter 15: Cellular Respiration
PSPM 2009/10
6. (a) Explain the steps in Krebs cycle that produce high energy molecules.
1
2
8
KREBS
CYCLE
3
4
7
6
5
[10 marks]
Chapter 15: Cellular Respiration
PSPM 2007/08
3. FIGURE 3 represents two main stages in cellular respiration.
(a) Name the reaction that occurs at steps 2, 3 and 4 and the
TWO by-products of the reaction.
(i) Reaction : ______ [1m] (ii) By-products: ______ [2m]
(b) At which step does the substrate level phosphorylation occur,
and how ATP(s) are produced at this step from one molecule
of glucose? (i) Step : _____
(ii) ATP(s) _______ [2m]
(c) State what happens to the hydrogen produced at step 6 [2m]
________________________________________________
________________________________________________
(d) Identify compound X. _________________ [1m]
(e) The reduced co-enzyme produced in step 1 will enter the
FIGURE 3
electron transport system.
(i) What is the reduced co-enzyme? _______ [1m]
(ii) What is the reaction involved in the production of ATP when the reduced co-enzyme in
e(i) enters the electron transport system? _________________ [1m]
Electron carriers:
NADH & FADH2
Electron Transport Chain
Oxidative phosphorylation: Electron Transport Chain & Chemiosmosis
•
ETC consists of 3 protein complexes: NADH
dehydrogenase complex, cytochrome
complex and two mobile carriers
•
The hydrogen atom from the NADH is
transferred to NADH dehydrogenase whereby
it will split into proton (H+) and electrons.
•
Electrons will reduce NADH dehydrogenase /
reductase while NADH is oxidized to NAD+ as
electron pass along the electron transport
chain.
•
As electron is transferred to ubiquinone
(Coenzyme Q), NADH dehydrogenase is
oxidized while ubiquinone will be reduced.
•
Electrons will be passed to cyctochrome b,
cytochrome b, and then cytochrome a.
•
The last electron acceptor is oxygen molecule.
Oxygen will be reduced to form water.
Oxidative phosphorylation: Electron Transport Chain & Chemiosmosis
•
Energy is released as electrons are passed along the electron transport chain. The
energy is used to pump hydrogen ions (H+) from the matrix to the intermembrane
space.
•
This builds up a gradient across the inner membrane of the mitochondrion.
•
Which forces H+ to diffuse through the ATP synthase down its concentration
gradient.
•
The energy released is used to synthesise ATP from ADP and Pi
•
This process is known as chemiosmosis.
Oxidative phosphorylation: Electron Transport Chain & Chemiosmosis
Oxidative Phosphorylation
uses process of
redox reactions
Chemisosmosis
as
which uses
electrons
proton gradient
from
inter membrane
space
NADH
passed down
Electron Transport
Chain
is pumped into
whereby
proton motive
force
to form
phosphorylation
to
undergo
ADP
H⁺
catalyzes
finally to
final electron
acceptor
ATP synthase
which is
oxygen
which is
ATP
producing
water
PSPM 2006/07
Chapter 15: Cellular Respiration
6. (a) Explain how electrons from NADH and FADH2 flow through the electron transport
chain with the production of ATP.
[12 marks]
PSPM 2006/07
Chapter 15: Cellular Respiration
6. (b) Compare and contrast between fermentation and aerobic respiration.
[8 marks]
PSPM 2004/05
Chapter 15: Cellular Respiration
6. (b) Describe the stages in the production of NADH and its role in cellular respiration.
[12 marks]
PSPM 2005/06
Chapter 15: Cellular Respiration
6. (a) Describe how one molecule of glucose is able to produce 36 ATP via aerobic
respiration.
[14 marks]
Reaction
ATP
1.
Glycolysis
2 ATP
2.
Krebs cycle
2 ATP
3.
ETC
• 2 NADH from link reaction
• 6 NADH from 2 Krebs cycle
• 2 FADH2 from 2 Krebs cycle
• Glycerol phosphate shuttle:
(2 NADH from glycolysis produce 2
FADH2)
Total
6 ATP
18 ATP
4 ATP
4 ATP
= 36 ATP
38 ATP from active cell
Reaction
ATP
1.
Glycolysis
2 ATP
2.
Krebs cycle
2 ATP
3.
ETC
• 2 NADH from link reaction
• 6 NADH from 2 Krebs cycle
• 2 FADH2 from 2 Krebs cycle
• Malate shuttle:
(2 NADH from glycolysis produce 2
NADH)
Total
6 ATP
18 ATP
4 ATP
6 ATP
= 38 ATP
Energy Harvested from Glucose
Glucose
(Cytoplasm)
2 ATP
(Mitochondrial
Matrix)
(Inner
Membrane)
Oxygen
4 ATP
Glycolysis
2 NADH
2 NADH
6 NADH
2 FADH2
2 Pyruvates
Krebs
Cycle
Electron Transport
System
2 CO2
4 CO2
2 ATP
Water
32 ATP
Anaerobic Respiration
PSPM 2004/05
Chapter 15: Cellular Respiration
6. (a) Compare between aerobic and anaerobic respirations.
[8 marks]
PSPM 2005/06
6.
Chapter 15: Cellular Respiration
(b) Explain the production of lactic acid during anaerobic respiration.
[6 marks]
PSPM 2009/10
Chapter 15: Cellular Respiration
6. (b) Discuss the fermentation pathways under anaerobic condition that occurs in plant
and animal cells.
[10 marks]
PSPM 2010/11
Chapter 15: Cellular Respiration
3. FIGURE 3 shows a schematic diagram of
cellular respiration.
(a) Name the type of cellular respiration
show in FIGURE 3.
_________________________ [1m]
(b) (i) State in what condition does the cellular respiration in
3(a) to occur.
_________________________ [1m]
(ii) Give ONE example of the importance of this process in
industry.
___________________________________
___________________________________ [1m]
(c) Name the process N. ______________________________________________
(d) Name the substances J,K, L and M.
Substance J : ___________________________________________________
Substance K : ___________________________________________________
Substance L : ___________________________________________________
Substance M : ___________________________________________________
(e) How many ATP molecules are produced from the process in FIGURE 3?
________________________________________________________________
(f) What is the role of NADH2 in the above process?
_________________________________________________________________
[1m]
[4m]
[1m]
[1m]
The Krebs cycle
Acetyl coenzyme A
Coenzyme A
Citrate
Oxaloacetate
NADH
NAD+
NAD+
CITRIC
ACID
CYCLE
H2O
NADH
CO2
FADH2
5-carbon compound
FAD
NADH
GTP
GDP
4-carbon compound
ADP
ATP
CO2
PSPM 2003/04
Chapter 15: Cellular Respiration
6. With reference to a labelled diagram, describe Krebs cycle.
[20 marks]
Cytosol
Outer mitochondrial
membrane
Intermembrane
space
Complex I: NADH–
ubiquinone
Inner
oxidoreductase
mitochondrial
membrane
Matrix of
mitochondrion
Complex II:
Succinate–
ubiquinone
reductase
Complex IV:
Cytochrome c
oxidase
Complex III:
Ubiquinone–
cytochrome c
oxidoreductase
FADH2
FAD
NAD+
NADH
2 H+
H2O
1/
2
O2
Cytosol
Outer
mitochondrial
membrane
Intermembrane
space
Inner
mitochondrial
membrane
Complex I
Matrix of
mitochondrion
Complex
II
Complex
III
Complex V:
ATP
synthase
Complex
IV
FADH2
NAD+
NADH
1
2
ADP
Pi
ATP
Outer mitochondrial
membrane
Cytosol
Inner mitochondrial
membrane
Intermembrane
space — low pH
Matrix — higher pH
Let’s count
Aerobic Respiration: Energy yield
Glucose
2
ATP
2
ATP
2 NADH
4/6
ATP
2 NADH
6
ATP
2
ATP
6 NADH
18
ATP
2 FADH2
4
ATP
Total net ATP yield = 36/38
ATP
Glycolysis
Pyruvate
Acetyl-CoA
Krebs
cycle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Tally the ATP
Substrate-level
phosphorylation
Glycolysis
Oxidative
phosphorylation
Glucose
Pyruvate
Acetyl
coenzyme A
Citric
acid
cycle
Total ATP from
substrate-level
phosphorylation
Total ATP from
oxidative
phosphorylation
Complete the table below
Glycolysis
Where does this occur in
the cell?
What are the input
molecules?
What is the carbonbased output molecule?
ATP production?
Electron carriers?
Formation of
Acetyl CoA and
Citric Acid Cycle
Electron
Transport and
Chemiosmosis
PSPM 2008/09
Chapter 15: Cellular Respiration
7. (a) Explain how protein and lipid are used as alternative energy source.
[8 marks]