Chapter 9
A. Cellular Respiration
• 1st Law of Thermodynamics
1. Energy flows into ecosystems as
sunlight  it is trapped and
transformed into chem. energy in
organic molecules  O2 is
released as a by-product
2. Some of the bond energy is used
to make ATP
3. Energy leaves living organisms as
heat.
4. The prod. Of respiration CO2 and
H2O are raw materials for
photosyn. Photosyn. prod. glucose
and oxygen the raw materials for
respiration.
5. Cellular respiration occurs in the
mitochondria.
Chapter 9
B. Cellular Respiration
1. Cellular respiration
involves 3 metabolic
steps that each make
ATP
a. Glycolysis
b. The citric acid cycle or
Kreb Cycle
c. Oxidation
phosphorylation
Cellular Respiration in the Mitochondria
Photosynthesis in the Chloroplast/C3 & C4 plants
Chapter 9
C. Cellular respiration
1. The cellular respiration that
occurs in your mitochondria
and is most prevalent in the
efficient catabolic pathway
2. It allows you to consume
oxygen and organic molecules
such as glucose- plant material
then yields ATP.
3. C6H12O6+6O2 6CO2 + 6H2O
36ATP
1. Oxidation-reduction RXN are
chem. RXN which involve a
partial or complete transfer of
electrons form one reactant
D. Redox reactions
to another redox RXN
2. Oxidation- loss of electronsbecomes oxidized
oxygen is a powerful oxidizing
C6H12O6 + 6O2
6CO2 + 6H2O + Energy
agent
3. Reduction gain of electrons
becomes reduced
4. Cellular respiration is a redox
becomes oxidized
RXN . Released energy is used
(loses electron)
to make ATP. Fats have high
energy storage. C-C-C rich in
Na
+
Cl
Na+ +
Cl–
carbon and hydrogen
Chapter 9
becomes reduced
(gains electron)
Chapter 9
E. Process of Cellular
Respiration
1. Glycolysis is a catabolic
pathway that occurs in the
cytosol. It partially oxidizes
glucose (C6) into two
pyruvate(C3) molecules.
Glycolysis occurs w/ or w/out
O2.
2.
Memorize the chart on the left.
Chapter 9
• Glycolysis Animation
• https://youtu.be/8Kn6BVGqKd8
Chapter 9
F. The Citric Acid Cycle or Tricoboxlic Acid
Cycle or Kreb Cycle
Pyruvate
(from glycolysis,
2 molecules per glucose)
Glycolysis
Citric
acid
cycle
ATP
ATP
Oxidative
phosphorylation
ATP
CO2
CoA
NADH
+ 3 H+ Acetyle CoA
CoA
CoA
FADH2
Citric
acid
cycle
FAD
3 NAD+
3 NADH
+ 3 H+
ADP + P i
ATP
Figure 9.11
2 CO2
1. Step 1 The unstable bond of acetyl
CoA breaks  two carbon acetyl
groups are made each one bonds
to the four carbon oxaloacetate to
form a six carbon citrate. To enter
the cycle twice.
2. Steps 2-7 During these steps,
Isocitrate loses CO2 leaving a 5
carbon cmpd & reducing NAD+.
3. Substrate level phosphorylation
occurs making ATP. FAD is oxidized
making FADH2 and a molecule of
NADH is made from malate. This
makes oxaloacetate to enter the
cycle again.
4. 6-NADH, 2-FADH, 2 ATP are made
5. Can I keep some sugar for my
oatmeal.
Pyruvate
(from glycolysis,
2 molecules per glucose)
Glycolysis
Citric
acid
cycle
ATP
ATP
Oxidative
phosphorylation
ATP
CO2
CoA
NADH
+ 3 H+
Acetyle CoA
CoA
CoA
Citric
acid
cycle
2 CO2
3 NAD+
FADH2
FAD
3 NADH
+ 3 H+
ADP + P i
ATP
Figure 9.11
Chapter 9
• Citric Acid or Kreb Cycle
Animation
Chapter 9
G. Oxidative Phosphorylation :
electron transport.
1. NADH and FADH2
a. Donate electrons to the electron
transport chain, which powers ATP
synthesis via oxidative
phosphorylation
2. Hydrogen, stripped from glucose are
1st accepted by NAD+ nicotinamide
adenine dinucleotide.
3. The 2 H+ from glucose make or
reduce NADH Placing the H+ on
NAD+ is called dehydrogenase
4. NAD+ oxidized
5. NADH reduced
Chapter 9
H. Chemiosmosis: The EnergyCoupling Mechanism
INTERMEMBRANE SPACE
H+
H+
H+
H+
H+
H+
H+
A rotor within the
membrane spins
clockwise when
H+ flows past
it down the H+
gradient.
A stator anchored
in the membrane
holds the knob
stationary.
H+
ADP
+
Pi
Figure 9.14
MITOCHONDRIAL MATRIX
ATP
A rod (for “stalk”)
extending into
the knob also
spins, activating
catalytic sites in
the knob.
Three catalytic
sites in the
stationary knob
join inorganic
Phosphate to ADP
to make ATP.
1. ATP synthase
a. Is the enzyme that actually
makes ATP
2. Energy rich electrons are
donated by coenzymes NADH
& FADH2. This occurs in the
inner membrane of the
mitochondria.
3. This exergonic RXN occurs as
oxygen accepts the H+
generating water, providing
energy to make ATP
Chapter 9
I. Electron transport chain
making 36 to 38 ATP
Glycolysis
ATP
Citirc
acid
cycle
ATP
1. This is located at the inner membrane of the mitochondrion.
2. It accepts energized electrons from reduced coenzymes NADH
and FADH2 .
3. Oxygen pulls these electrons down the electron transport chain
to a lower energy state.
4. This exergonic slide of electrons to water and ATP synthesis. This
makes 90% of the ATP
5. Energy is released as hydrogen is pumped into the
intermembrane from NADH and FADH
Inner
Mitochondrial
membrane
Oxidative
phosphorylation
electron transport
and chemiosmosis
ATP
H+
H+
H+
Intermembrane
space
Q
I
Inner
mitochondrial
membrane
Mitochondrial
matrix
H+
Cyt c
Protein complex
of electron
carners
IV
III
II
FADH2
NADH+
NAD+
(Carrying electrons
from food)
FAD+
2 H+ + 1/2 O2
ATP
synthase
H2O
ADP +
ATP
Pi
H+
Chemiosmosis
Electron transport chain
+
ATP
synthesis
powered by the flow
Electron transport and pumping of protons (H ),
+
+
Of H back across the membrane
which create an H gradient across the membrane
Oxidative phosphorylation
1. Fermentation allows some cells
to make ATP w/out oxygen.
Chapter 9
J. Fermentation-Another metabolic
process
2. Food can be oxidized under
anaerobic conditions.
3. Aerobic- w/oxygen
4. Under Aerobic conditions,
pyruvate is oxidized, & ATP is
made as NADH passes in
electron transport chain.
5. Anaerobic conditions, pyruvate
is reduced & NAD+ is made,
then recycled to continue w/
the break down of glucose.
Chapter 9
K. Fermentation
• Two common types of fermentation
are alcohol fermentation, which
produces ethanol.
• Lactic acid fermentation it is the 2nd
type. –Usually made by muscles low
on oxygen. Pyruvate is reduced to
lactate. Lactic acid accumulates in
the muscles.—Cramps
• ATP is made by sub-level oxidative
phosphorylation
Chapter 9
L. Controlling Cellular
Respiration
Glucose
AMP
Glycolysis
Fructose-6-phosphate
–
Inhibits
Stimulates
+
Phosphofructokinase
–
Fructose-1,6-bisphosphate
Inhibits
Pyruvate
Citrate
ATP
Acetyl CoA
Citric
acid
cycle
Oxidative
phosphorylation
1. Cells respond to changing
metabolic needs by
controlling reaction rates.
2. Anabolic pathways are
switched off when their
products are plentiful.
3. The common method of
control is feedback
inhibition.
N. CAM plants
(photochromates-quinone)
Chapter 10
1. These are called the succulent
plants that live in very arid
locations.
2. They open their stomata primarily
at night and close them during the
day to prevent H2O loss.
3. CAM stands for crassulacean acid
metabolism.
4. The organic acids made at night
are stored in vacuoles of
mesophyll cells until the morning
when the stomata close.
5. The stored CO2 from the acids are
used to make ATP during the day.
Then at night CO2 is fixed into a
carbon chain, outside of the Calvin
Cycle.
Inside a Chloroplast
H2O
CO2
Light
NADP+
ADP + P
Lightdependent
reactions
Calvin
Calvin
cycle
Cycle
Chloroplast
O2
Sugars
A. Photosynthesis
Chapter 10
1. Transform light energy trapped
inside chloroplast into chemical
bond energy stored in glucose.-This
is done by autotrophs-plants.
2. Autotrophs can store energy made
w/light photoautotrophs.
3. Chemiautotrophs make energy
w/chemical oxidation.
4. Heterotrophs eat autotrophs
Chapter 10 Light RXN
C. Chloroplast
Chapter 10
1. Intermembrane space- The chloroplast is
bound by a double membrane which
partitions its contents from the cytosol
6CO2+12H2O+light  C6H12O6 + 6O2 +6H22.OThylakoid space- Thylakoids form
membranous spaces and systems w/in the
chloroplast
3. Stroma- RXN’s that convert CO2 to sugar
occurs here.
4. 6CO2+12H2O+light  C6H12O6 + 6O2 +6H2O
5. Photosynthesis is a Redox process that is
endergonic because energy is required to
reduce CO2
D. Light RXN & the Calvin Cycle
Chapter 10
1. Photosynthesis occurs in 2 stages;
Light RXN’s & the Calvin Cycle
2. Light RXN steps:
3. a) begins in thylakoid.-NADP+ is
reduced to NADPH. The H is used to
split H20 giving off O2.
4. b) ATP is generated from
phosphorylation of ADP
Chapter 10
E. Light RXN & the Calvin Cycle
1. The Calvin Cycle is the
carbon fixing RXN that
changes CO2 in
carbohydrates.
2. These RXN’s occur in the
stroma of the chloroplast.
3. Light is not needed for
this RXN,
but the by products of the
light RXN are needed
NADPH, ATP
F. Light RXN closer look
1. Explain
Chapter 10
2. The wavelike properties of light
or electromagnetic energy have a
range from 380nm to 750nm,
which is what we see.
3. Light energy is measured in
photons, which are proportional
to the wavelength
4. The pigment in the leaf absorbs
light energy. Leaves are green
because blue and red are
absorbed and the green reflects
back
G. Chlorophyll
Chapter 10*
1. Explain
2. Chlorophyll a, is the light absorbing
pigment that participates w/ light
directly. The porphyrin ring on the
chlorophyll molecule absorbs light
3. The other chlorophyll’s are called
accessories.
4. Chlorophyll b, a yellow-green
pigment contain carotenoids- which
are yellow and orange hydrocarbons.
H. Photosystems I & II
Chapter 10
1. The photosystems, located in the thylakoid
membranes.
2. Photosystem I, has a chlorophyll a, that responds to
700nm light.
3. Photosystem II, has a chlorophyll a, that responds
to 680nm light.
4. Both systems are noncyclical it
passes electrons continuously from
H2O to NADP+/ It produces
NADPH,O2, & ATP from
photophosphorylation
Chapter 10
I. Cyclic electron flow
1. This step only involves photosystem
I, and generates ATP, w/out prod.
NADPH or oxygen.
2. As photons are absorbed by
photosytem I, an excited e is
released, where it goes to P700nm,
this allow ATP to be produced.
3. Another 2 photons of light are
absorbed, which makes more ATP
w/out NADPH or O2, because
enough ATP is not made
J. Chemiosmosis in chloroplast and
mitochondria
1. Chemiosmosis is a combined exergonic
and endergonic RxN
2. This is an ATP production that is based
upon an electrochemical difference
across a membrane.
3. The inner mitochondrial membrane
produces ATP.
4. ATP is produced as protons diffuse
from the thylakoid to the stroma
Chapter 10
Chapter 10
K. Calvin Cycle
1. The Calvin Cycle is similar to the Kreb Cycle
in that the starting material is regenerated
by the end of the cycle.
2. Carbon enter the Calvin Cycle as CO2 and
leaves as sugar.
3. ATP is the energy source, while NADPH is
the reducing agent that adds high energy
electrons to form sugar.
4. The Calvin cycle actually prod. A 3 carbon
sugar glyceraldehyde phosphate.
5. The Calvin Cycle uses 18ATP and 12 NADPH
to prod. One glucose molecule.
1. Photorespiration is a metabolic
L. Alternate carbon
pathway that reduces photosynthesis
by consuming Oxygen, evolving CO2
fixation models for hot
and making no ATP. This is control
arid locations
method for Oxy. Amounts.
2. C4 plants unlike most plants, use the
Calvin cycle to produce a 4 carbon
chain from CO2, instead of the 3
carbon chain like most plants
3. C4 plants include corn, sugar cane
and grasses. Most plants use the
enzyme rubisco to fix CO2. Rubisco
does not work under hot and dry
conditions.
Chapter 10