Respiration & Photosynthesis
By: (The only) Titus Yeh
Remember this REACTION!!!
Respiration
Photosynthesis
Remember this REACTION!!!
Respiration
Photosynthesis
Cellular Respiration
• Cellular Respiration is a cellular process
that breaks down nutrient molecules with
the concomitant production of ATP
• Hmm…sounds like a difficult definition, but
the main point of Respiration is:
- To generation energy from carbon in the
form of ATP
- Aerobic respiration
Brief points of Respiration
• The three major carbohydrate energy
producing reactions are glycolysis, the
citric acid cycle (Krebs), and the electron
transport chain.
Glycolysis: Basic
• Glycolysis is the breakdown of glucose
into two molecules of pyruvate
- Occurs in the cytoplasm (cytosol)
- ATP is formed
- Does not utilize oxygen
Glycolysis: Process
- 2 ATP are added
- 2 NADH are produced
- 4 ATP are produced
- 2 pyruvate are formed.
In summary, glycolysis takes 1 glucose and
turns it into 2 pyruvate, 2 NADH, and a net
of 2 ATP (made 4 ATP, but used 2 ATP).
Animation: How Glycolysis Works
• http://highered.mcgrawhill.com/sites/0072507470/student_view0/
chapter25/animation__how_glycolysis_wo
rks.html
Road Block
• Remember about the reaction I told you in
Slide 2?
• In glycolysis, glucose is used.
• So lets put a check on glucose.
Fermentation
• Anaerobic respiration (fermentation)
occurs in the cytoplasm when not enough
oxygen is present for the cell to utilise the
electron transport chain. The purpose of
both fermentation processes is to free
NADH for use in glycolysis.
Fermentation
• Alcoholic fermentation: occurs in plants,
fungi, and bacteria. Each pyruvate is
converted to a molecule of ethanol and
one NADH is used in the reaction.
• Lactate fermentation: occurs in animals
& mammals (humans). Each pyruvate is
converted to lactate and one NADH is
used in the reaction.
The Krebs Cycle: Before
• The Krebs cycle, also known as the citric
acid cycle, occurs in the matrix of
mitochondria and requires pyruvic acid,
the product of glycolysis. Pyruvic acid
combines with coenzyme A (a vitamin) to
form acetyl CoA, which enters the Krebs
cycle.
The Krebs Cycle: Before
• Although the Krebs cycle is described for 1
pyruvate, remember that glycolysis
produces 2 pyruvate.
• Therefore just remember to x2 to the
cycle. Haha 
The Krebs cycle: After
• One turn of the Krebs cycle releases:
- 3 NADH
- 1 ATP
- 1 FADH2
- CO2
Remember what you should do?
Answer: X2
Citric Acid Cycle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
NADH
e–
NADH
e–
e–
e–
e–
Glycolysis
glucose
pyruvate
e–
Electron transport
chain and
chemiosmosis
Citric acid
cycle
Preparatory reaction
e–
NADH and
FADH2
Matrix
2 ATP
2 ADP
4 ADP
2
4 ATP total
ATP
net
2ADP
2
ATP
acetyl CoA
C2
32ADP
or 34
32
or 34
1. The cycle begins when a
C2 acetyl group carried by
CoA combines with a C4
molecule to form citrate.
CoA
ATP
oxaloacetate
C4
Citric Acid Cycle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
NADH
e–
NADH
e–
e–
e–
e–
e–
NADHand
FADH2
e–
Glycolysis
Citric acid
cycle
Preparatory reaction
glucose
pyruvate
Electron transport
chain and
chemiosmosis
Matrix
2 ATP
2 ADP
4 ADP
2
4 ATP total
ATP
net
2ADP 2
ATP
32ADP
or 34
32
or 34
ATP
CoA
acetyl CoA
C2
1. The cycle begins when a
C2 acetyl group carried by
CoA combines with a C4
molecule to form citrate.
citrate
C6
oxaloacetate
C4
Citric Acid Cycle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
NADH
e–
NADH
e–
e–
e–
e–
e–
NADHand
FADH2
e–
Glycolysis
Citric acid
cycle
Preparatory reaction
glucose
pyruvate
Electron transport
chain and
chemiosmosis
Matrix
2 ATP
2 ADP
4 ADP
2
4 ATP total
ATP
net
2ADP 2
ATP
32ADP
or 34
32
or 34
1. The cycle begins when a
C2 acetyl group carried by
CoA combines with a C4
molecule to form citrate.
CoA
ATP
acetyl CoA
C2
citrate
C6
NAD
NADH
oxaloacetate
C4
2. Twice over, substrates
are oxidized as NAD+ is
Reduced to NADH,
and CO2 is released.
CO2
ketoglutarate
C5
Citric Acid Cycle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
NADH
e–
NADH
e–
e–
e–
e–
e–
NADHand
FADH2
e–
Glycolysis
Citric acid
cycle
Preparatory reaction
glucose
pyruvate
Electron transport
chain and
chemiosmosis
Matrix
2 ATP
2 ADP
4 ADP
2
4 ATP total
ATP
net
2ADP
2
ATP
32ADP
or 34
32
or 34
1. The cycle begins when a
C2 acetyl group carried by
CoA combines with a C4
molecule to form citrate.
CoA
ATP
acetyl CoA
C2
citrate
C6
NAD
NADH
oxaloacetate
C4
2. Twice over, substrates
are oxidized as NAD+ is
Reduced to NADH,
and CO2 is released.
CO2
ketoglutarate
C5
NAD+
succinate
C4
CO2
ATP
NADH
3. ATP is produced as an
energized phosphate is
transferred from a
substrate to ADP.
Citric Acid Cycle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
NADH
e–
NADH
e–
e–
e–
e–
NADHand
FADH2
e–
e–
Glycolysis
Citric acid
cycle
Preparatory reaction
glucose
pyruvate
Electron transport
chain and
chemiosmosis
Matrix
2 ATP
2 ADP
4 ADP
2
4 ATP total
ATP
net
2ADP
2
ATP
32ADP
or 34
32
or 34
1. The cycle begins when a
C2 acetyl group carried by
CoA combines with a C4
molecule to form citrate.
CoA
ATP
acetyl CoA
C2
citrate
C6
NAD
NADH
oxaloacetate
C4
2. Twice over, substrates
are oxidized as NAD+ is
Reduced to NADH,
and CO2 is released.
CO2
fumarate
C4
ketoglutarate
C5
NAD+
succinate
C4
FAD
4. Again a substrate is
oxidized, but this time
FAD is reduced to FADH2
CO2
NADH
FADH
ATP
3. ATP is produced as an
energized phosphate is
transferred from a
substrate to ADP.
Citric Acid Cycle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
NADH
e–
NADH
e–
e–
e–
e–
e–
NADHand
FADH2
e–
Glycolysis
Preparatory reaction
glucose
Electron transport
chain and
chemiosmosis
Citric acid
cycle
pyruvate
Matrix
2 ATP
2 ADP
4 ADP
2
4 ATP total
ATP
net
2ADP
2
ATP
32ADP
or 34
32
or 34
ATP
CoA
1. The cycle begins when a
C2 acetyl group carried by
CoA combines with a C4
molecule to form citrate.
acetyl CoA
C2
citrate
C6
NAD
NADH
oxaloacetate
C4
NADH
5. Once again a substrate
is oxidized, and NAD+
is reduced to NADH.
2. Twice over, substrates
are oxidized as NAD+ is
Reduced to NADH,
and CO2 is released.
Citric acid
cycle
NAD+
CO2
fumarate
C4
ketoglutarate
C5
NAD+
succinate
C4
FAD
4. Again a substrate is
oxidized, but this time
FAD is reduced to FADH2
CO2
NADH
FADH
ATP
3. ATP is produced as an
energized phosphate is
transferred from a
substrate to ADP.
Animation: How the Krebs Cycle
Works
• http://highered.mcgrawhill.com/sites/9834092339/student_view0/
chapter7/how_the_krebs_cycle_works.htm
l
Road Block
• The CO2 produced by the Krebs Cycle is
the CO2 animals and mammals exhale
when they breathe.
• Remember what is left in the reaction that
was 18 slides before this slide?
• O2 is not used in the Krebs Cycle.
Electron Transport Chain (ETC)
• Location:
- Eukaryotes: cristae of the mitochondria
- Aerobic prokaryotes: plasma membrane
• The ETC:
- Receives electrons from NADH & FADH2
- Produces ATP by oxidative phosphorylation
• Oxygen serves as the final electron acceptor:
- Oxygen combines with H+ and e- to form
water
Electron Transport Chain (ETC)
• The fate of the hydrogens:
- The electrons from NADH pass through
three proteins which pump a total of 6
protons across the cristae.
- The electrons from FADH2 pass through
two proteins and pump a total of 4 protons
across the membrane.
Electron Transport Chain (ETC)
• The ETC complexes pump H+ across the
cristae (matrix to the inter-membrane space of
the mitochondrion).
• H+ becomes more concentrated in the intermembrane space  electrochemical gradient.
• ATP synthase allows H+ to flow down its
gradient.
• Flow of H+ through the ATP synthase creates
ATP out of ADP and inorganic phosphate
• This process is called chemiosmosis
Electron Transport Chain (ETC)
• Through chemiosmosis, a total of about
34-38 ATP is produced.
• ATP is then moved out of the mitochondria
and is used for cellular work.
Animation: ETC and ATP Synthesis
• http://highered.mcgrawhill.com/olcweb/cgi/pluginpop.cgi?it=swf::5
35::535::/sites/dl/free/0072437316/120071
/bio11.swf::Electron%20Transport%20Syst
em%20and%20ATP%20Synthesis
Animation: Proton Pump
• http://highered.mcgrawhill.com/olcweb/cgi/pluginpop.cgi?it=swf::5
35::535::/sites/dl/free/0072437316/120068
/bio05.swf::Proton%20Pump
Road Block
•
•
•
•
Remember about the reaction?
O2 is used during ETC
Let’s put a check on O2 then.
Since both reactants are used, this shows
that we are done with respiration.
Hmm…
What’s next?
I guess it is time for Photosynthesis.
Remember this REACTION again!!!
Respiration
Photosynthesis
Photosynthesis
• The next three slides are some facts you need
to know before you learn photosynthesis in
depth.
• They might make you sleep, but trust me, they
are really important.
• So slap yourself in the face, and stretch a little
before you start looking at the next few slides
Photosynthetic Organisms
• In plants, carbon dioxide and water are
converted into glucose and oxygen.
• Photosynthetic organisms have special
organelles in their cells called chloroplasts,
which are double membrane bound
organelles. Chloroplasts, much like
mitochondria and respiration, are the site of
photosynthesis.
Photosynthetic Organisms
• Also like mitochondria, chloroplasts
themselves have several specific
compartments and specially functioning
organelles.
• The area between the outer membrane
and the inner membrane (thylakoid) is
called the stroma, this space is where the
light-independent reactions happen.
Photosynthetic Organisms
• Inside the chloroplast, several granum are
usually very neatly arranged. Each
granum is a stack of thylakoids, which
small sacs containing chlorophyll actually
carry out the process of photosynthesis.
• Remember: It is this chlorophyll which
gives plant leaves their coloration (usually
green).
Leaves and Photosynthesis
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
cuticle
upper
epidermis
Leaf cross section
mesophyll
lower
epidermis
CO2
O2
leaf vein
outer membrane
stoma
inner membrane
stroma
stroma
granum
Chloroplast
37,000
thylakoid space
thylakoid membrane
Grana
independent thylakoid
in a granum
overlapping thylakoid
in a granum
© Dr. George Chapman/Visuals Unlimited
36
The Process of Photosynthesis
• Light Reactions – take place only in the
presence of light
- generate energy from light
• Light Independent Reaction (Calvin
Cycle Reaction) – take place in the
stroma
- fix carbon from the atmosphere into
complex sugars
Solar Energy Converters
• The Light Reactions consist of two
separate pathways:
- Noncyclic Pathway
- Cyclic pathway
Each of which uses energy from light to
produce high energy molecules that the cell
can use in the light independent reactions.
• Captures light energy with photosystems
• Occurs in the thylakoid membrane
Noncyclic Photophosphorylation
Cyclic Photophosphorylation
1. A photon of light excites Photosystem
II, which ejects electrons that come
from the split of water (O2, H+, e-)
2. These electrons are picked up and
passed through various proteins
(ETC), pumping hydrogen ions across
the thylakoid membrane.
3. This movement of protons causes
phosphorylation of one ATP
(chemiosmosis)
4. A photon of light hitting Photosystem I
causes an ejection of two electrons.
5. The electron is transfereed
permanently to a molecule of NADP+,
which causes NADPH production.
6. These products then enter the lightindependent reaction.
1. A photon of light excites Photosystem
I, which ejects electrons
2. These electrons then passed through
a chain of proteins (ETC), which pump
hydrogen ions across the thylakoid
membrane.
3. No NADPH is produced, but the
electrons then return to Photosystem
I, and the cycle begins again
Noncyclic Electron Pathway
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
H2 O
CO2
solar
energy
ADP+ P
NADP+
Light
reactions
sun
Calvin
cycle
sun
NADPH
ATP
thylakoid
membrane
energy level
electron
acceptor
electron
acceptor
O
CH2O
e–
e–
e–
e–
NADP+
H+
ATP
e–
NADPH
e–
reaction center
reaction center
pigment
complex
pigment
complex
Photosystem I
e–
Photosystem II
CO2
H2O
CH2O
Calvin cycle
reactions
2H+
1
– O2
2
40
Solar Energy Converters
• Remember that the non-cyclic pathway
makes both NADPH and ATP, while the
cyclic pathway only makes ATP.
• The Calvin Cycle (Light-Independent
Reaction) requires more ATP than
NADPH, so this is a way for the cell to
regulate the amount of ATP and NADPh
available for the Calvin Cycle
Animation: Noncyclic & Cyclic
Photophoshorylation
• http://highered.mcgrawhill.com/sites/9834092339/student_view0/
chapter39/cyclic_and_noncyclic_photopho
sphorylation.html
Photosynthetic ETC and ATP
Synthesis
• http://highered.mcgrawhill.com/sites/9834092339/student_view0/
chapter39/photosynthetic_electron_transp
ort_and_atp_synthesis.html
Road Block
• Hopefully by now YOU know the reaction
by heart…haha I’m just saying
• In this light-dependent reaction, H2O is
being used.
• So let’s put a check on H2O.
• Two more reactants to go!!
Light-Independent Reactions (LIR)
• As its name has suggest, the reaction can
occur with or without the presence of light.
• It is also known as the C3 photosynthesis
• Involves three stages:
- Carbon dioxide fixation
- Carbon dioxide reduction
- RuBP regeneration
The Calvin Cycle (LIR): summary
• In the Calvin cycle, carbon enters as CO2,
and leaves as a three-carbon sugar,
glyceraldehyde-3-phosphate (G3P). Each
round of the Calvin cycle fixes carbon from
1 molecule of CO2 which means that it
takes 3 turns to make 1 G3P, or 6 turns to
make 1 molecule of glucose. So overall it
costs the cell 18 ATP and 12 NADPH to
make each molecule of glucose.
The Calvin Cycle Reactions
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
H2 O
CO2
solar
energy
ADP + P
NADP +
Light
reactions
Calvin
cycle
NADPH
ATP
Metabolites of the Calvin Cycle
stroma
O2
CH2O
RuBP
ribulose-1,5-bisphosphate
3PG
3-phosphoglycerate
BPG
1,3-bisphosphoglycerate
G3P
glyceraldehyde-3-phosphate
3 RuBP
C5
47
The Calvin Cycle Reactions
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
H2 O
CO2
solar
energy
ADP + P
NADP +
Light
reactions
Calvin
cycle
NADPH
ATP
Metabolites of the Calvin Cycle
stroma
O2
CH2O
3CO2
RuBP
ribulose-1,5-bisphosphate
3PG
3-phosphoglycerate
BPG
1,3-bisphosphoglycerate
G3P
glyceraldehyde-3-phosphate
3 RuBP
C5
48
The Calvin Cycle Reactions
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
H2 O
CO2
solar
energy
ADP + P
NADP +
Light
reactions
Calvin
cycle
NADPH
ATP
Metabolites of the Calvin Cycle
stroma
O2
CH2O
3CO2
intermediate
3 C6
RuBP
ribulose-1,5-bisphosphate
3PG
3-phosphoglycerate
BPG
1,3-bisphosphoglycerate
G3P
glyceraldehyde-3-phosphate
3 RuBP
C5
49
The Calvin Cycle Reactions
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
H2 O
CO2
solar
energy
ADP + P
NADP +
Light
reactions
Calvin
cycle
NADPH
ATP
Metabolites of the Calvin Cycle
stroma
O2
CH2O
3CO2
intermediate
3 C6
3 RuBP
C5
RuBP
ribulose-1,5-bisphosphate
3PG
3-phosphoglycerate
BPG
1,3-bisphosphoglycerate
G3P
glyceraldehyde-3-phosphate
6 3PG
C3
50
The Calvin Cycle Reactions
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
H2 O
CO2
solar
energy
ADP + P
NADP +
Light
reactions
Calvin
cycle
NADPH
ATP
Metabolites of the Calvin Cycle
stroma
O2
CH2O
3CO2
intermediate
3 C6
3 RuBP
C5
6 3PG
C3
RuBP
ribulose-1,5-bisphosphate
3PG
3-phosphoglycerate
BPG
1,3-bisphosphoglycerate
G3P
glyceraldehyde-3-phosphate
6
ATP
6 ADP + 6 P
6 BPG
C3
51
The Calvin Cycle Reactions
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
H2O
CO2
solar
energy
ADP + P
NADP +
Light
reactions
Calvin
cycle
NADPH
ATP
Metabolites of the Calvin Cycle
stroma
O2
CH2O
3CO2
intermediate
3 C6
6 3PG
C3
3 RuBP
C5
RuBP
ribulose-1,5-bisphosphate
3PG
3-phosphoglycerate
BPG
1,3-bisphosphoglycerate
G3P
glyceraldehyde-3-phosphate
6
ATP
6 ADP + 6 P
These ATP and
NADPH molecules
were produced by
the light reactions.
6 BPG
C3
6 NADPH
6 G3P
C3
6 NADP+
52
The Calvin Cycle Reactions
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
H2O
CO2
solar
energy
ADP +
P
NADP +
Calvin
cycle
Light
reactions
NADPH
ATP
Metabolites of the Calvin Cycle
stroma
O2
CH2O
3CO2
intermediate
3 C6
RuBP
ribulose-1,5-bisphosphate
3PG
3-phosphoglycerate
BPG
1,3-bisphosphoglycerate
G3P
glyceraldehyde-3-phosphate
6 3PG
C3
3 RuBP
C5
6
ATP
6 ADP + 6 P
These ATP and
NADPH molecules
were produced by
the light reactions.
6 BPG
C3
6 NADPH
6 G3P
C3
6 NADP+
net gain of one G3P
Other organic molecules
Glucose
53
The Calvin Cycle Reactions
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
H2O
CO2
solar
energy
ADP +
P
NADP +
Calvin
cycle
Light
reactions
NADPH
ATP
Metabolites of the Calvin Cycle
stroma
O2
CH2O
3CO2
intermediate
3 C6
RuBP
ribulose-1,5-bisphosphate
3PG
3-phosphoglycerate
BPG
1,3-bisphosphoglycerate
G3P
glyceraldehyde-3-phosphate
6 3PG
C3
3 RuBP
C5
6
ATP
6 ADP + 6 P
These ATP and
NADPH molecules
were produced by
the light reactions.
6 BPG
C3
6 NADPH
5 G3P
C3
6 G3P
C3
6 NADP+
net gain of one G3P
Other organic molecules
Glucose
54
The Calvin Cycle Reactions
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
H2O
CO2
solar
energy
ADP +
P
NADP +
Calvin
cycle
Light
reactions
NADPH
ATP
Metabolites of the Calvin Cycle
stroma
O2
CH2O
3CO2
intermediate
3 C6
3 RuBP
C5
3 ADP + 3
ribulose-1,5-bisphosphate
3PG
3-phosphoglycerate
BPG
1,3-bisphosphoglycerate
G3P
glyceraldehyde-3-phosphate
6 3PG
C3
CO2
fixation
6
ATP
CO2
reduction
Calvin cycle
P
RuBP
6 ADP + 6 P
These ATP and
NADPH molecules
were produced by
the light reactions.
regeneration
of RuBP
These ATP
molecules were
produced by the
light reactions.
6 BPG
C3
3
ATP
6 NADPH
5 G3P
C3
6 G3P
C3
6 NADP+
net gain of one G3P
Other organic molecules
55
Glucose
Animation: How the Calvin
Cycle Works
• http://highered.mcgrawhill.com/sites/9834092339/student_view0/
chapter39/calvin_cycle.html
Road Block
• Please tell me what is the reaction?
• Hmmm…if you really don’t know at this
point, you should really wake up and start
studying.
• In the Calvin Cycle, CO2 and ATP are
used up.
• Thus, let’s put a check on them.
Other Types of Photosynthesis
• In hot climates,
Stomata closes  CO2 decreases  O2 increases
 O2 combines with RuBP  leads to the
production of CO2  photorespiration
• C4 plants solving the problem of photorespiration
- Fix CO2 to PEP ( a C3 molecule), which results in
a C4 molecule called oxaloacetate
- In hot & dry climates, C4’s net productivity is 2-3
times greater than C3 plants, but in cool & moist
environments, C4 plants compete with C3 plants.
- C4 plants consist of sugarcane and corn.
Other Types of Photosynthesis
• CAM Photosynthesis
- Partition carbon fixation by time
- During the night
1. CAM plants fix CO2
2. Forming C4 molecules
- During the day
1. NADPH and ATP are available
2. Stomata are closed due to conservation
3. C4 molecules release CO2 to the Calvin
Cycle
Hmm…
• I guess that is all from me…
• I have tried my best to impart my wisdom
to you people.
• Well…I will help you guys clarify one more
thing.
Chemiosmosis in Chloroplasts and Mitochondria
Similarities
Differences
• Used to generate ATP
• Energy from ETC used to pump
protons across a membrane
• Creates a H+ gradient across
membrane
• ATP synthase uses energy from
diffusion of H+ ions back across
membrane to generate ATP
• Some electron carriers
(cytochromes) are similar in both
chloroplasts/mitochondria
• Oxidative phosphorylation in
mitochondria
• Photophosphorylation in
chloroplasts
• Mitochondria transfer chemical
energy from food molecules to ATP
• Chloroplasts transform light energy
into ATP
• Mitochondrial inner membrane
pumps protons from the matrix out
to the inter-membrane space
• Chloroplast thylakoid membrane
pumps protons from the stroma into
the thylakoid space
Yeah
• I guess this is all…
• I tried my best to summarize and find the
best information there is.
• As what Mrs. Yu would always say, READ
YOUR BOOK!
• Yeah that’s all.
• The END