Big Idea 2:
Biological systems utilize free energy and molecular building blocks
to grow, to reproduce and to maintain dynamic homeostasis.
Enduring understanding 2.A:
Growth, reproduction and maintenance of the organization
of living systems require free energy and matter.
Essential knowledge 2.A.2: Organisms capture and
store free energy for use in biological processes.
Subobjective 2.4: I can use representations to
pose scientific questions about what
mechanisms and structural features allow
organisms to capture, store and use free energy.
How do photoautotrophs capture free energy?
Define photoautotroph
An organism that makes its
own food (organic compounds)
using free energy from the Sun
What is light?
Electromagnetic radiation that
we can see
This is an X-ray image of the Sun
Describe the electromagnetic spectrum
The range of light radiation
What is a photon?
The quantum unit or particle of electromagnetic radiation
Each photon has a fixed quantity of energy that is related to
wavelength
The shorter the wavelength the more energy a photon has
You need to have conceptual understanding of the next 3
slides, but the details are above and beyond the course
Photons of light from the visible spectrum can cause electrons
in certain pigments to jump to a higher energy level, which
means they are temporarily more energetic.
Describe how electrons gain and lose energy
Electrons gain and loose
energy in discrete packets
They absorb exactly
enough to jump from one
energy level to another
They emit exactly enough
energy to fall from one
energy level to another
A photon of light
at some energy
level is absorbed
by an electron at
some energy
level
The electron is elevated to a
higher and unstable energy
level
The heat energy released is equal to the
difference in the energy of the absorbed
photon and the emitted photon. The total
energy emitted is equal to the energy
absorbed.
A photon of a
light of slightly
lower energy is
emitted
The electron
returns to its
original stable
energy level
http://micro.magnet.fsu.edu/primer/java/scienceopticsu/exciteemit/index.html
Define protein
A sequence of amino acids
that fold up taking on a
shape that determines
their function
https://www.youtube.com/watch?
v=lijQ3a8yUYQ
Define pigment
A protein that absorbs certain
wavelengths of light
Chlorophyll a (a
pigment)
Explain the graph
The dependent
variable is how much
light is absorbed by
chlorophyll a at a given
wavelength
The independent variable is
wavelength of visible light (400nm is
much more energetic light than
700nm)
Define spectrophotometer
A device that directs
photons of light of various
wavelengths through a
solution and measures the
amount of radiation that is
transmitted
Explain the graph
High
absorption
No
absorption
Medium
absorption
This is why chlorophyll and therefore photosynthetic leaves are
green!
Use the absorption spectrum of
photosynthetic pigments found
in plants to explain why leaves
are green in the summer and
red/orange/yellow in the fall
Chlorophyll is the main pigment used to
trap free energy from the Sun. It absorbs
wavelengths of light that are longer and
shorter than green wavelengths and it
reflects green light. Long warm days are
good conditions for turning free energy
from the Sun into the potential energy in
the bonds that hold sugar molecules
together. So the plant produces lots of
chlorophyll and the leaves appear green
during the summer.
Short, cold days are not good
conditions for photosynthesis.
Plants respond by absorbing
the chlorophyll pigments and
recycling them to conserve
energy. This leaves other
pigments such as carotenoids
behind. Carotenoids absorb
short wavelengths and reflect
longer wavelengths resulting in
yellows and oranges that were
always there, but masked by
green chlorophyll.
Cyanobacteria and protists also use
chlorophyll pigments to capture
energy from the Sun to drive the
photosynthesis of sugars.
Phytoplankton (various protists also
called algae)
How do chemoautotrophs capture free energy?
Watch video before continuing
https://www.youtube.com/watch?v=D69hGvCsWgA
6CO2 + 6H2O +3H2S → C6H12O6 + 3H2SO4
Define chemoautotroph
An organism that uses
the free energy in the
bonds holding
inorganic molecules
together to make its
food (synthesize
organic compounds)
6CO2 + 6H2O +3H2S → C6H12O6 + 3H2SO4
The energy
needed to
put CO2
molecules
together
comes from
H2S
Explain how
sugar is made
by
chemosynthesis
Sugar
is made by
putting
CO2
molecules
together
Volcanic vents provide the energy for forming
Hydrogen sulfide (H2S)
What are the macromolecules heterotrophs and
autotrophs utilize to derive the free energy
necessary to drive endergonic reactions?
Define polymer
A molecule made of similar or identical molecules
covalently bonded together
How do polymers form?
By dehydration reactions (a type of
condensation reaction)
Define carbohydrate
One or more saccharide (sugar) molecules covalently bonded
together. They have many functions including being a source
for free energy storage.
Define disaccharide
A carbohydrate composed of 2 monosaccharides
Define polysaccharide
A carbohydrate composed of many monosaccharides
Define lipid
A macromolecule that is not a polymer. They have many
functions. Fat is a type of lipid that provides insulation,
protection, and storage of free energy
What macromolecules can be
utilized for free energy by
heterotrophs?
Carbohydrates, lipids, and
proteins
Watch the video. You
need to understand
what hydrolysis is, but
not the minutia of the
mechanism involved
How do autotrophs and
heterotrophs get free energy from
macromolecules?
hydrolysis
https://www.youtube.c
om/watch?v=0XGiIE9b
9QU
How does NAD+ behave like an electron shuttle?
Define enzyme
A protein catalyst. It speeds up reactions and doesn’t get
used up in the reaction (watch the video below)
http://www.youtube.com/watch?v=CZD5xsOKr
es&NR=1
Define active site
The substrate binding region of the enzyme
What is an oxidative – reduction reaction? (Redox reaction
for short)
A reaction where one species gains electrons therefore
becoming reduced by taking electrons from another
species, which is oxidized
http://www.youtube.com/watch?v=e6Xxz-VBE6s&NR=1
What is a reducing agent?
A substance that donates electrons (it becomes oxidized)
What is an oxidizing agent?
A substance that receives electrons (it becomes reduced)
What is the equation for the cellular respiration of glucose?
C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy (ATP + heat)
Label the reducing agent, oxidizing agent, the molecule that
gets reduced, and the molecule that gets oxidized for the
equation below
C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy (ATP + heat)
Reducing agent
becomes
oxidized
Oxidizing agent
becomes
reduced
Watch the videos below if you are having trouble understanding
https://www.khanacademy.org/science/biology/cellular-molecular-biology/cellular-respiration/v/oxidation-and-reduction-frombiological-view
https://www.khanacademy.org/science/biology/cellular-molecular-biology/cellular-respiration/v/oxidation-and-reduction-incellular-respiration
How does NAD+ get electrons?
This is stored
energy in the form
of high energy
electrons
What does the equation below mean?
An enzyme took electrons from the –OH group of a carbon
compound and added them to NAD+. So the carbon
compound has been oxidized (it lost free energy) and NAD+
has been reduced to NADH (it gained free energy).
Subobjective 2.5: I can construct explanations
of the mechanisms and structural features of
cells that allow organisms to capture, store or
use free energy.
How do heterotrophs capture free energy?
They consume organic molecules from autotrophs,
chemotrophs, or other heterotrophs and then catabolize
these molecules utilizing the free energy in the organic
molecules to make ATP.
Define substrate-level phosphorylation
ATP synthesis mediated
by enzymes that
transfer a phosphate
group from a molecule
(substrate) to ADP
The intermediate molecules
and enzymes involved are
beyond the scope of the
course, but useful to
discuss
Glycolysis
Sugar
Cutting
Characteristics of glycolysis
1) It is nearly universal (nearly all organisms utilize this
10 step process)
2) It occurs in the cytoplasm
3) It is anaerobic (does NOT use oxygen)
4) It provides ATP energy quickly
5) It only gets a small amount of the energy available
in glucose out
The ancestor of all life on
the planet evolved the
glycolysis metabolic
pathway
What is the evolutionary significance of glycolysis?
It provides strong evidence for common ancestry of all life on
the planet
The first evidence for life is 3.5-3.8 billion years ago, but
no measurable amounts of oxygen were present in the
atmosphere until 2.7 billion years ago
Glycolysis occurs in the cytoplasm so it doesn’t require
the membrane bound structures present in eukaryotic
cells that didn’t evolve until about 2.5 billion years ago
Glycolysis is a nearly universal pathway for ATP synthesis
that is an evolutionary relic of a time before there was
oxygen on Earth
What you need to know about the metabolic pathway
called glycolysis
2 high energy NADH
molecules
1 glucose
molecule
Results in
2 ATP used get
things started
2 Net ATP
2 pyruvate
***No oxygen is used (anaerobic), occurs quickly, lots of
potential energy is left
For a complete explanation, watch the video
https://www.khanacademy.org/science/biology/cellular-molecularbiology/cellular-respiration/v/glycolysis
Must be oxidized to restore NAD+ so
glycolysis can continue
Glycolysis
Reactants
1 glucose molecule
2 NAD+ molecules
2 ATP molecules
Products
2 pyruvate molecules
2 NADH molecules
4 ATP molecules
ATP is generated by substrate level phosphorylation by the
oxidation of glucose. NAD+ oxidizes glucose, so without NAD+ no
ATP can be generated
A unicellular fungus
we call yeast
In the absence of oxygen, yeast restore NAD+ by
oxidizing pyruvate (CO2 and alcohol are by products)
Define alcohol fermentation
NAD+ is regenerated by reducing
pyruvate to ethanol
Your cells utilize a different way of oxidizing NADH in the
absence of oxygen
Define lactic acid fermentation
NAD+ is regenerated by reducing pyruvate to lactate
What happens to the products of glycolysis?
Cellular respiration is a 5
step process
1) Glycolysis
2) Pyruvate oxidation
3) Kreb’s cycle (also called the citric acid
cycle)
4) The electron transport chain
5) Oxidative phosphorylation by ATP
synthase
anaerobic
Not with
oxygen
aerobic
with oxygen
What are mitochondria?
Organelles (small cellular
structures) that produce the
majority of the ATP used by the cell
What is the evolutionary origin of mitochondria?
Mitochondria are likely the ancestors of a type of purple
bacterium that was consumed by some archean cell. The
bacterium and archean cells developed a symbiotic
relationship where the bacterium specialized in producing
energy and the archean cell specialized on feeding
What the video
https://www.youtube.com/watch?v=q71DWYJD-dI
Define oxidative phosphorylation
ATP synthesis driven by
the redox reactions of
the electron transport
chain. Inorganic
phosphate is added to
ADP by ATP synthase
Where do the 5 stages of cellular respiration occur and what
type of ATP synthesis occurs at each stage?
What happens to acetyl CoA?
The intermediate molecules of the Kreb’s cycle are beyond the
course. You need to know the products of the Kreb’s cycle
including the names of the 2 electron carriers (NADH, and
FADH2)
How does the structure of mitochondria fit their function?
Matrix
Structure fits function—
the highly folded inner
membrane increases
surface area and
therefore the number of
protein complexes for
ATP synthesis
Inner
membrane
space
What you need to know about the Kreb’s cycle
1) It occurs within the matrix of the mitochondria
2) The remnants of glucose are completely
oxidized
3) 2 carbon dioxide (CO2) molecules per acetyl CoA
are produced
4) The end result is just 2 ATP (1 per acetyl CoA
5) Most of the available energy in the 2 acetyl CoA
molecules produced by glycolysis that enter the
Kreb’s cycle is stored in high energy electrons of
6 NADH and 2 FADH2 molecules
What you need to know
about the Kreb’s cycle
Remember that each
glucose molecule results
in 2 pyruvate so multiply
the output illustrated by 2
Where do the high energy electrons of the electron
transport chain come from and why is oxygen
essential for electron flow?
http://vcell.ndsu.nodak.edu/animations/etc/movie-flash.htm
What you need to know about the electron
transport chain
1) It occurs in the inner membrane of the mitochondria
2) A proton gradient is made by passing high energy electrons
taken from NADH and FADH2, which are produced in the
Kreb’s cycle
 FADH2 loses its electrons at a lower energy level than
NADH so it produces about a third of the energy NADH
does
3) Molecular oxygen (O2) is the final electron acceptor in the
electron transport chain and must be present for electron
transport to continue
4) The vast majority of the ATP generated from a glucose
molecule comes from oxidative phosphorylation utilizing a
proton gradient generated by the electron transport chain
How is the free energy of the proton gradient
generated by the electron transport chain used to
make ATP?
Define chemiosmosis
Energy stored in the form of a
hydrogen ion H+ gradient
across a membrane is utilized
to generate ATP
Define proton-motive force
The capacity of the H+ gradient
to do work (generate ATP)
established by the electron
transport chain
Concentration gradient of protons
Pi
Protons moving through
ATP synthase cause it to
rotate
ADP
Rotating ATP synthase orients ADP
and Pi into a position that is
energetically favorable for the
formation of ATP
http://vcell.ndsu.nodak.edu/animations/atpgradient/movie-flash.htm
A summary of how the electron transport chain generates ATP
The electron transport chain
squeezes as much energy
out of each electron as
possible creating a proton
gradient
ATP synthase utilizes the
potential energy of the
proton gradient to make ATP
the energy currency of all life
What is the total ATP yield from one glucose
molecule? (don’t memorize specific numbers)
NADH → 2.5 ATP
FADH2 → 1.5 ATP
Glycolysis
2NADH
2ATP
Krebs cycle
and pyruvate
oxidation
NADH = 10 X 2.5 = 25ATP
2FADH2 = 2 X 1.5 = 3ATP
8NADH
= 4ATP
2FADH2
= 32 maximum
2ATP
How is the rate of glycolysis synchronized to the
rate of the Kreb’s cycle?
Enzyme activity (watch video before continuing)
http://www.youtube.com/watch?v=PILzvT3spCQ
Describe the ways chemicals inhibit enzyme function
You need to understand how the products of enzymes
allosterically inhibit the enzymes that make them by a
negative feedback mechanism
http://highered.mheducation.com/sites/0072943696/student_view0/chapter2/
animation__feedback_inhibition_of_biochemical_pathways.html
Define feedback inhibition
A metabolic pathway
that is switched off by
the inhibitory binding of
its end product to an
enzyme that acts early in
the pathway
This is analogous to how
heat pumps work
(you don’t have to memorize
the names of the enzymes)
Respiration is regulated by
negative feedback inhibition
Glycolysis is slowed when
ATP concentration and
citrate concentration is
high
Both products of
respiration inhibit the
enzyme
phosphofructokinase,
which is activated by AMP
How is phosphofructokinase activity regulated?
Allosterically by AMP, ATP, and Citrate
Since both citrate and ATP accumulation inhibit this enzyme,
glycolysis and the Kreb’s cycle are synchronized
As ATP is depleted, ADP is generated and converted to AMP
Accumulation of AMP is
a signal that ATP is low
What is an example of an alternative to oxygen as a
final electron acceptor?
Define anaerobic respiration
The complete breakdown of organic molecules for energy
using a final electron acceptor other than oxygen
http://en.wikipedia.org/wiki/Anaerobic_respiration#Examples_of_respiration
What is the difference between fermentation
and anaerobic respiration?
Both generate ATP
without using oxygen
Utilizes an electron
transport chain and
therefore generates ATP
by oxidative
phosphorylation
Generates ATP by
substrate level
phosphorylation only
therefore it generates
much less ATP
What is an example of an organism that produces ATP
by anaerobic respiration?
Sulfate reducing
bacteria use sulfate as
an electron accepter in
an analogous way that
we use oxygen. The
result is hydrogen
sulfide (H2S), which is
the rotten egg smell,
rather than H2O.
Various types of anaerobic bacteria exist and they can be used in
bioremediation depending on the type of molecule they reduce
What are the structures involved in
photosynthesis?
Plants need 4 things to survive
1)
2)
3)
4)
Soil
Water
Sun
Air
Where does the vast
majority of plant mass
come from?
Photosynthesis is an emergent property of 3 different processes that
are interdependent
•Photosystem II
•Photosystem I
•The Calvin Cycle
The light dependent (“photo”) reactions
The light independent (“synthesis”)
reactions
Where do the light dependent
reactions occur?
In the membranes of the
thylakoids
Where do the light dependent
reactions occur?
In the stroma
What are chloroplasts?
Organelles within plant
cells and some protists
where photosynthesis
occurs
What is the evolutionary origin of chloroplasts?
An endosymbiotic relationship developed between a
photosynthetic bacterium and a phagocytic eukaryote
Notice the similarities in the structures of cyanobacteria and
chloroplasts. There is strong evidence to support the claim that
the ancestors of modern day cyanobacteria where eaten and
then took up residence in a primitive eukaryotic cell
Where are chloroplasts
found?
The green parts of plants
Define stomata
Openings in a leaf that
allow for gas exchange
Granum
Thylakoid
Stroma
Define stroma
The fluid interior of the inner membrane of the chloroplast
(analogous to the cytosol)
Define thylakoids
Stacked sacs within the stroma that contain photosystems II
and I within their membranes
How do we know the absorption spectrum of chloroplasts?
How do we know
chlorophyll a directly
participates in
photosynthesis?
The action spectrum
for photosynthesis
The action spectrum
for photosynthesis is
measured by O2
released (b) and by
where bacteria are
found in an alga
illuminated by
different wavelengths
of light (c)
Why doesn’t the action
spectrum of chloroplasts
exactly match the absorption
spectrum of chlorophyll a?
Although chlorophyll a is the
primary photosynthetic
pigment, chlorophyll b and
carotenoids are
photosynthetically important
as well
Why does each pigment have a different absorption
spectrum?
Photons of light have specific amounts of energy and
electrons only absorb photons that will increase their energy
to another energy level (no halvsies)
As a result, slight differences in the atoms a pigment is
composed of OR the molecules the pigment is associated with
affect what photons of light will be absorbed
Where does the oxygen produced by
photosynthesis come from?
6CO2 + 12H2O +
→ C6H12O2 + 6H2O + 6O2
Water
How do we know the oxygen produced by photosynthesis comes
from water?
Plants grown with water labeled with the heavy oxygen isotope
O18 produce oxygen with the oxygen isotope O18
What experiment showed that the oxygen produced during
photosynthesis in plants doesn’t come from CO2?
Van Niel showed that photosynthetic sulfur bacteria
produced sulfur during photosynthesis, not oxygen, as a
waste product and reasoned that photosynthesis
requires a hydrogen source and CO2.
Sulfur bacteria
CO2 + 2H2S → [CH2O] + H2O + 2S
Plants
CO2 + 2H2O → [CH2O] + H2O + O2
General
CO2 + 2H2X → [CH2O] + H2O + 2X
The light reactions of
photosynthesis
Where do the electrons that flow through
photosystems II and I come from and where do
these electrons get their free energy?
Where is chlorophyll found?
In the thylakoid membranes of plant cells
Define photosystem
A reaction-center complex surrounded by light-harvesting complexes
Organized proteins
surrounding a pair of
chlorophyll a molecules
Various pigment molecules
(chlorophyll a chlorophyll b,
and carotenoids) bound to
proteins
What are the advantages of having various light-harvesting
pigments?
1) Carotenoids protect chlorophyll a from high energy
photons that would otherwise damage the pigment
2) The chloroplast can utilize photons over a larger
spectrum of light improving photosynthetic output
Why do the chlorophyll a molecules in the reaction centers of
photosystems II and I absorb slightly different wavelengths of
light?
They are surrounded by different proteins in the thylakoid
membrane which results in slightly different electron
distributions
Let’s take a closer look at
the thylakoid membrane
Watch the video before
continuing. The names of the
electron carriers, proton
pumps and enzymes are
beyond the scope of the
course, but useful to talk
about
http://vcell.ndsu.nodak.edu/animations/photosynthesis/photosystemII_01.htm
A pair of chlorophyll a
molecules
The photon of light causes an electron
from chlorophyll a to be excited. This
electron is taken by the primary electron
acceptor
This makes the
chlorophyll molecule
really mad. It becomes
highly electronegative
and the most powerful
oxidizing molecule
known to man.
No more electrons will
be excited enough by
photons for the primary
electron acceptor to
take them
So photosystem II is
shut down. Right?
An enzyme splits a water molecule
into 2 electrons, 2 protons, and an
oxygen atom
The oxygen gas leaves
the plant through the
stoma
And the oxygen atom
immediately binds with
another oxygen atom
The chlorophyll is more
electronegative than oxygen
so it grabs an electron that
was split from the water
molecule
Now the chlorophyll is
“recharged”, and not quite so
angry so it has electrons that
can be excited enough by a
photon to be taken away by
the primary electron acceptor
again
You need to know where the light dependent reactions of
photosynthesis occur in photosynthesizing bacteria,
photosynthesizing protists (algae), and plants.
You need to know the role of chlorophyll a, what it is, where
it is found, where it gets electrons, and how its electrons gain
free energy
Photons of light are absorbed by electrons in chlorophyll
a. A photon gives an electron free energy. Excited
electrons are taken from chlorophyll a to an electron
transport chain in photosystem II and to NADP+ in
photosystem I. Chlorophyll a gets more electrons from
water.
What is the role of NADP+ and what is
purpose of electron flow?
The electron carrier
plastoquinone takes the
electron from the
primary electron
acceptor
Plastoquinone takes the
electron to the
cytochrome complex
which is an electron
transport chain
What do
you think
happens
here?
Why?
It’s more
electronegative
The electron is passed to
more and more
electronegative molecules.
The reduction in the free
energy of the electron is
used to pump protons
from the stroma to the
thylakoid lumen
The enzyme
plastocyanin takes the
electron from the
cytochrome complex
Why?
It’s more
electronegative
If the electron is not
taken from
plastocyanin, it won’t
take another electron
from the cytochrome
complex
What would happen?
The cytochrome complex wouldn’t take an electron
from plastoquinone, plastoquinone wouldn’t take an
electron from the primary electron acceptor, and the
primary electron accept wouldn’t take the excited
electron from chlorophyll a.
This would be like the
electron transport chain
in cellular respiration
running out of oxygen
As a result, the excited electron of the chlorophyll
a electron would fall back to its unexcited state,
and the energy would be radiated out into space
This doesn’t happen
Why?
The cytochrome complex wouldn’t take an electron
from plastoquinone, plastoquinone wouldn’t take an
electron from the primary electron acceptor, and the
primary electron accept wouldn’t take the excited
electron from chlorophyll a.
If the electron is not
taken from
plastocyanin, it won’t
take another electron
from the cytochrome
complex
An electron from the
chlorophyll a pair of
photosystem I is excited by a
photon of light
The primary electron
acceptor grabs the excited
electron from chlorophyll a
So photosystem I
allows
photosystem II to
be more efficient
Now the chlorophyll is
extremely electronegative,
and is able to grab an
electron from plastocyanin
Does photosystem II
help photosystem I at
all?
Once the primary electron accepter
takes an electron form chlorophyll a,
chlorophyll a will not give up another
one
Yes
Why?
How?
The electron taken from water is passed along to
the chlorophyll a molecule of photosystem I which
allows chlorophyll a electrons excited by photons
of light to be given up once again
Chlorophyll a
becomes too
electronegative
to give up an
electron. Even
one that is
excited by a
photon of light
Without more NADP+ to reduce, photosystem I slows and
Let’sSo
follow
the
electron
flow
+ plays
photosystem II slows as well.
NADP
oxygen’s
role in the electron transport chain in cellular respiration
as final electron acceptor
NADPH is oxidized during the
glyceraldehyde 3 phosphate
production that occurs in the
Calvin Cycle
Photon e
ee-
Photon
Without the NADPH and ATP production that occurs in
photosystems II and I, the Calvin cycle could not produce
enough carbon compounds for a plant to survive
NADP+
An
Plastoquinone
Plastocyanin
A
The
Chlorophyll
Ferredoxin
photon
enzyme
cytochrome
primary
reductase
ofgrabs
rips
alight
electron
grabs
grabs
takes
apart
complex
the
excites
takes
the
the
the
electron
a water
two
an
molecule
grabs
acceptor
electron
from
electrons
the
thefrom
takes
primary
freeing
from
electron
chlorophyll
plastocyanin
the
ferredoxin
up
electron
excited
an aand
electron
aacceptor
hydrogen ion from the
stroma and adds them to
NADP+
Photon e
ee-
Photon
Photons What’s
of light the
excite
point
electrons.
of all this
These
electron
excited
movement?
electrons are passed
to molecules of greater and greater electronegativity. The free
energy loss is used to pump H+ into the thylakoid and reduce NADP+.
This creates a concentration gradient that is used to make ATP just
like in cellular respiration.
What do the light reactions generate and how?
How much ATP is generated by photosystem I?
Zero
The electrons from
photosystem II generate
a proton gradient, which
is used to make ATP
The electrons from
photosystem I are used to
reduce NADP+ to NADPH
What do we call
this process?
Chemiosmosis
http://vcell.ndsu.nodak.edu/animations/atpgradient/movie-flash.htm
How do mitochondria and chloroplasts
generate ATP?
chemiosmosis
How is chemiosmosis in
mitochondria and
chloroplasts different?
The electrons used to
make a proton
gradient to generate
ATP in mitochondria
come from organic
molecules, while those
used by chloroplasts
Mitochondria use chemical energy to
come from water
make ATP and chloroplasts transform light
energy into chemical energy in ATP
The light reactions and
chemiosmosis
Don’t memorize specific numbers or
names of electron carriers
How does the Calvin cycle use the chemical energy
of ATP and NADPH to reduce CO2 to sugar
The dark reactions of photosynthesis
What are the 3 phases
of the Calvin Cycle?
1) Carbon fixation
2) Reduction
3) Regeneration of
CO2 acceptor
Do memorize that 3 CO2 enter
one at a time and the product is
1 G3P sugar molecule used to
make glucose and other carbon
compounds. The ATP and NADPH
used to reduce CO2 comes from
photosystems II and I. The Calvin
cycle is essential for restoring the
NADP+ used as the final electron
acceptor in photosystem I
Do not memorize the names of
the intermediate molecules ,
enzymes or specific numbers
http://www.youtube.com/watch?v=o1I33Dgcc_M
How did life on Earth change after the evolution of
photosynthesis?
Watch and then describe
the oxygen catastrophe
https://www.youtube.com/watch?v=DE4CPmTH3xg
Subobjective 2.41: I can evaluate data to show
the relationship between photosynthesis and
respiration in the flow of free energy through a
system.
What is the evidence that supports the relationship
between photosynthesis and respiration?
Plants, some
bacteria, and some
protists
photosynthesize.
They use the
carbon compounds
made by
photosynthesis to
get ATP through
cellular respiration.
Explain the graph below
Oxygen consumption is
the dependent variable
so we know this is a
graph illustrating how
something affects
cellular respiration
Time is the dependent variable. Since the
dependent variable is an amount we know we are
measuring the rate of cellular respiration
Explain the graph below
We can conclude
that germinating
peas have higher
metabolic rates
than seeds
regardless of
temperature and
both seed and
germinating seeds
have higher
metabolic rates at
20⁰C than at 10 ⁰ C
Beads were used as a
control to measure
changes in oxygen not
do to cellular respiration
The legend tells us the
rate of cellular
respiration was
measured at various
temperatures
Explain the graph
below in terms of
cellular respiration,
photosynthesis and
primary productivity.
Mauna Loa is in Hawaii.
As photosynthesis
increase so does
primary productivity
The dependent variable
is the amount of CO2 in
the atmosphere and
the independent
variable is month
Days begin to shorten
significantly in the fall
(September). The
decrease in sunlight
and air temperatures
decreased
photosynthesis.
Plants, animals, and the
rest of life on the planet
have to breathe, so CO2
increases.
Days begin to lengthen
significantly in the
summer (June). Sunlight
and air temperatures
increase photosynthesis.
Photosynthesis
removes CO2 from the
atmosphere.
Although cellular
respiration adds CO2,
photosynthetic rate is
higher than the rate of
cellular respiration in the
summer, but lower in
the fall, winter, and
spring