Transcript Photosynthesis Cellular Respiration

Chapter 9
Photosynthesis
& Cellular Respiration
Our Earth
• Our Earth is an anomaly, it’s
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•
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•
•
weird.
By chance, the perfect
combinations of atmospheric
conditions; temperature, gravity,
and combinations of molecules
exist in a perfect balance to
support life.
Supporting life is just one
aspect that makes studying our
living situation, studying biology
relevant.
The fact that Earth can sustain
life, much more important, is
supported by a fundamental
ability for the planet to recycle
building blocks of life.
One of the blocks being, of
course, carbon.
Carbon, because of its bonding
flexibility, is the perfect
candidate to form the basic
building block of all
biomolecules.
Do You Recall?
Organic Compounds
• Name some compounds
that has CARBON as the
primary building block.
The Essential Questions
• How is energy produced on Earth?
• What molecules is energy stored in?
• What is photosynthesis?
The Essential Questions
• How do we go from energy that travels
millions of miles from the sun as light…
• …to the chemical potential energy in
glucose…
• …to the kinetic energy of ATP being broken
down?
ENERGY!
Objectives Photosynthesis &
Cellular Respiration
• Define photosynthesis.
• Show how photosynthesis and cellular respiration are
related processes.
• State the 2 steps of photosynthesis.
• Determine what the reactants and products of
photosynthesis are.
• Locate where photosynthesis takes place (inside of leaves).
• Determine the types of and the roles of pigments in
photosynthesis.
• Determine the role the environment plays in photosynthesis.
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Illustrate how glycolysis produces ATP.
Recite how ATP is produced in aerobic respiration.
Define fermentation and when fermentation takes place.
Define the two types of fermentation.
The Carbon Cycle
• Revisit the carbon-cycle.
• You should know that carbon is cycled
through the environment and passes
through various organisms and
processes.
• Two key steps in the carbon cycle happen when…
• 1. Photosynthesis is the process where plants take
carbon dioxide and water and produce sugar and
oxygen.
• 2. In cellular respiration animals (and plants) convert
the sugar into ATP with the use of oxygen.
• All of this requires the initial activation energy from the
sun to start the chemical reactions…
Photosynthesis
• 2 reaction steps:
• Light reactions:
– Trap sunlight
energy and store it
in electron carriers
ATP & NADPH
• Dark reactions
– Use the energy in
the electron carriers
to convert carbon
dioxide (CO2) into
sugar.
Ultimately All Energy Comes From the
Sun
• The sun emits rays called photons.
• They travel through space as waves and
reach our Earth, warming it and providing
energy in the form of heat.
• These rays also power the carbon cycle,
which allows carbon to be cycled from
organisms to the air in various carbon
compounds.
– Carbon dioxide
– Glucose
Where the Cycle Begins
• Starts with light hitting autotrophs
– These include plants, algae, and
bacteria.
• The light, which is a form of
energy, drives photosynthesis
• The chemical equation above
represents photosynthesis, a
chemical reaction that uses
carbon dioxide & water to form
glucose & oxygen powered by
the sun.
Photosynthesis Takes Place in
Chloroplasts
Plant Pigments
In the thylakoid
membrane there
are photosystems
that contain
pigments.
These pigments
are responsible for
•
absorbing
particular
wavelengths of
light.
There are 4 major pigments,
in 2 categories.
– Chlorophyll = chlorophyll a & b
– Carotenoids = carotene and
xanthophyll
Pigment Extraction
• Most leaves have more
than one kind of
pigment.
• We usually only notice
the green (the
dominant pigment) but
upon close examination
one can see the others.
• Some plants change
colors in the fall and
utilize the carotenoids
during this season as
the energy source.
Plants Have Preferences
• Plants absorb only certain colors for photosynthesis.
• It is directly related to the pigments in their light receptors…
like chlorophyll…. & how energetic the color is.
• Chlorophyll is a the pigment stuck in the membrane of thylakoids in
chloroplasts that absorbs light energy to start photosynthesis.
• It absorbs energetic blue and red light and reflects green and yellow
light.
• There are other pigments, like carotenoids, as well. These absorb other
wavelengths of light that chlorophyll doesn’t, which helps plants
maximize the amount of available light to use for making energy.
What’s Special About Light?
• Energy travels as waves.
• Waves have two features.
– Amplitude … how tall they are.
– and wavelength … how far apart the crests are.
• Visible light is only a small fraction of all energy
waves in space.
• This is the visual light spectrum.
• Plants use specific wavelengths within this
spectrum as energy to power photosynthesis.
Harnessing the Energy From Light
• Light Reactions: When
sunlight is absorbed.
• Absorbed light is energy
that is transferred to
electron carriers.
• The products =
electrons carriers,
NAPDH & ATP, and
molecular oxygen, O2.
• NADPH & ATP is used
later …oxygen is
actually released by
chloroplasts as waste.
The Light Reactions of Photosynthesis
NADPH
H+
e
The Products
of the Light
Reactions
ATP
What You Need to Know
• What is the chemical equation for
photosynthesis and what does it mean?
• What are pigments (names and
functions)?
• What is produced in the first stage of
photosynthesis?
• Where does photosynthesis take place?
Once Energy is Captured…
• DARK REACTIONS:
• Once energy is temporarily
captured in the NADPH it is
used to power what’s called
the “DARK REACTIONS”
in the Calvin Cycle.
– They’re called dark because
they don’t need sunlight.
• The Calvin Cycle “fixes”
carbon dioxide into 6 carbon
sugars.
• These eventually become
glucose and other sugars.
The Energy Provided By
Photosynthesis
The Overall Net Result of
Photosynthesis
• The overall result of photosynthesis is that for every 6
carbon dioxide molecules (plus 6 water) that a plant
uses, 1 glucose molecule (plus 6 oxygen) is created.
Other Considerations with
Photosynthesis
• Photosynthesis is temperature and light
dependent.
– There is an optimal temperature, about 30 degrees
Celsius, where photosynthesis operates most
efficiently.
– The amount of sunlight determines photosynthesis
efficiency as well, affecting the evolution of deciduous
trees to loose there leaves when there isn’t as much
sunlight (fall & winter).
• Photosynthesis also influences global carbon
dioxide and oxygen levels.
– When photosynthesis is going at a high rate it will
affect atmospheric CO2 & O2 levels accordingly.
Concept Check
• Write the complete equation for photosynthesis.
• Make sure you include the quantities of each
molecule.
• Once completed, explain what the equation
means.
• The equation means that plants use the carbon
dioxide we breath out and the water in the
environment to produce sugar and oxygen.
Concept Check
• Where does the energy for photosynthesis come
from?
• From the sun.
• Which organisms perform photosynthesis?
• Autotrophs, like plants.
• Where does the carbon dioxide needed come from?
• It comes from organisms, like humans, that
respire (breath it out).
• State the photosynthesis equation in words.
• Photosynthesis uses light energy to convert
carbon dioxide and water from the atmosphere
into sugar, releasing oxygen into the
environment as waste.
1. During which of the following months is the rate of photosynthesis greatest?
A. May
B. March
C. January
D. September
2. If the data were obtained from the atmosphere over an evergreen forest (a forest that never
loses its leaves – like pine trees), the curve likely would
A. rise from February to May and fall from August to November.
B. vary less throughout the year.
C. rise steadily from January to December.
D. fall steadily from January to December.
3. If the y-axis of a graph displayed the rate of
transpiration (effected by temperature) of a
deciduous forest (a forest where tress lose
their leaves in the fall), the curve likely would
A. rise from February to May and fall from
August to November.
B. vary little throughout the year.
C. rise steadily from January to December.
D. fall steadily from January to December.
Photosynthesis Leaf Model
Construction
• It is time to summarize what you’ve
learned about photosynthesis and
leaves.
• Obtain the three sheets on the demo
table.
• Follow the directions and construct
your leaf model.
• Place the arrows in appropriate
locations on your leaf.
• Check your leaf in with me when you
are done for 25pts (lab).
• Use this leaf as a study guide.
Complete your
handout.
Use this illustration as a template for the
cross section of your leaf.
Use pgs. 558-561 of blue books for leaf anatomy.
What to do now.
• “What’s In A Leaf” – Save WS until Tuesday.
• Leaf Foldable Photosynthesis Model – Turn in at end of
class. Use this illustration as a template for the cross
section of your leaf.
Wed/Thurs Feb 12-13, 2014
Agenda:
Discussion: Cellular Respiration.
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Have cycles & PhotoCR H/O out
Practice with Photosynthesis
---------Warm Up--------1. Photosynthesis is part of what
cycle?
2. What are the two steps in
photosynthesis?
3. If I said you were part dinosaur
how could that be true?
---------Homework---------
Complete your
readings/outlines/vocabulary
By Next Tuesday.

Important:
- Test will be 2/21 (Friday)
- Core: CH5 COMPLETE
vocabulary is due 2/18.
- Honors: CH7/8 outline due
Tuesday 2/21.
- Honors: Don’t forget your
project progress report
date is 2/18 as well. The
outline of your
experiment… don’t fall
behind!
Shamrock Update…
Mendoza- 54.00
Davitt- 36.00
Banda- 32.00
Metzger- 24.00
Admin- 24.00
Ives- 16… wanna be the
biggest contributing class
towards giving a kid a
priceless opportunity?
OXYGEN
Making Glucose
The First Half of
the Carbon Cycle
• This is only half of the
carbon cycle.
• Once glucose is made,
energy is fixed in the
bonds between carbons
and stored.
• It needs to be released in
order for the cycle to
continue.
• The energy is ultimately
stored so it can be
released to form the
universal energy
currency…ATP.
Aerobic Cellular Respiration
• The release of the potential energy in
glucose is accomplished in the reversed
form of the photosynthesis chemical
reaction.
• This is known as aerobic cellular respiration.
Cellular Respiration
How Cells Create ATP
• Cellular Respiration accomplishes the task of
releasing the energy in glucose (& other
macromolecules).
• There are two phases in Respiration.
• Glycolysis:
Occurs in the cytoplasm
• The creation of ATP…
Occurs in mitochondria
Cellular Respiration
Glycolysis
The initial step is glycolysis… to make pyruvate.
Input
SUGAR + 2 ATP
Output
4 ATP + Pyruvate
Visual Concept: Glycolysis
Break
• Stand
• Look at a neighbor.
• Take turns, one tell the other what the
equation for cellular respiration is in
common words.
• The other tell what the equation is for
photosynthesis.
From Glycolysis…
• Glycolysis occurs in all organisms, with the purpose of creating
pyruvates (3-carbon sugars).
• What happens next is dependent upon whether there is
oxygen present or not.
• If oxygen is present, the pyruvates that are formed in glycolysis
are transported to the mitochondria where the cell creates more
electron transporters in the Krebs cycle.
• Without oxygen, pyruvate is used to form ATP through
fermentation.
With O2:…Pyruvate To The Krebs Cycle
FOR EACH PYRUVATE!
x2 FOR 1 GLUCOSE
With O2: The Krebs Cycle
Why The Krebs Cycle?
• The Krebs cycle does produce ATP but
only 2 per pyruvate.
• The real benefit for the Krebs cycle is to
produce electron carriers.
– NADH (3)
– FADH2 (1)
• These molecules carry electrons in bonds
to the electron transport chain…
the real site of ATP synthesis.
The Final Step:
The Electron Transport Chain
The Net Result
Without
O2
The Net Result
is 4 ATP
1
Glucose
With
O2
The Net Result
is 38 ATP
The Cycle Completed
• Once glucose is broken down in the electron transport
chain, Carbon dioxide and water is released and the
maximum number of ATP is created.
• The products of respiration are available to fuel
photosynthesis and the carbon cycle starts over.
Without Oxygen
• When you have
exhausted the O2 in
your blood you can still
produce ATP, just not
as efficiently, through a
process called
fermentation.
= sore muscles = alcohol
• In animals, we produce
lactic acid, which is
recycled back into
glycolysis to produce 2
ATP… not very
efficient.
• In plants and some
other organisms (like
yeast), this process
creates ethanol, also
called alcohol, which
can go back into
glycolysis.
Why Do We Care About ATP?
• ATP is our body’s
energy “currency”.
– It’s made in
mitochondria and
spent everywhere
else.
• It is the most
important energy
molecule we need
to survive.
ATP: The Cell’s Energy Currency
ATP Stores & Releases Energy
ENERGY!
ATP USES
• The structure on the right is a mitochondria.
• This is where ATP production takes place.
• From this illustration, tell me, does ATP production take
place in just animal cells?
• No. Plant cells also have mitochondria to produce ATP.
ATP Molecules Quick Facts
• Your body uses, on average, 1,000,000 molecules
of ATP per cell, per second.
• We use it for muscle contractions, like a heart beat,
or to grow, or to heal, or to fight disease, or to think,
or to transport molecules across membranes, or to
create bigger molecules.
• Your body has roughly 1,000,000,000,000 cells.
• That’s roughly 100,000,000,000,000,000,000 ATP
molecules used EVERY SECOND!
• We can only create ATP if we consume quality food
and have plenty of oxygen present.
• Does eating good sound important yet?
What You Should Know
1. What is photosynthesis?
2. What is the chemical equation?
3. Where does it take place?
4. Where do plants get the reactants from?
5. How do plants accumulate & absorb sunlight?
6. What is cellular respiration?
7. What is the equation?
8. Where does it take place?
9. Where do mitochondria get the reactants?
10. What is the difference between aerobic and anaerobic
respiration?
11. How the reactions of photosynthesis & cellular respiration
related.
12. How many ATP are produced from 1 molecule of glucose in
aerobic respiration?
Concept Check
Describe, using words, the equation of cellular respiration?
Cellular respiration takes glucose and oxygen and creates ATP, giving carbon dioxide off as a
byproduct.
Where does cellular respiration take place?
In mitochondria
Which organisms go through aerobic respiration?
Any organism that has mitochondria; both animals AND plants
What are the three steps to aerobic cellular respiration?
Glycolysis – Krebs – ETC
What is produced (& in what quantity) in glycolysis?
2 pyruvate
What is produced (& in what quantity) in the Krebs cycle?
Electron carriers, 3 NADH & 1 FADH2
What (& in what quantity) is produced in the electron transport chain?
ATP (and a lot) 34 per glucose
What does aerobic mean?
In the presence of oxygen
What does anaerobic mean?
Without oxygen
When we exercise heavily and deplete our bodies of most of our oxygen, how do we produce ATP?
Fermentation
What are the two processes of fermentation?
Lactic Acid (in humans and animals) & Alcohol (plants, bacteria, protists like yeast)
CHECK STUDY GUIDES
CELLULAR RESPIRATION
PHOTOSYNTHESIS
GLUCOSE
SUN
2
GLYCOLYSIS
O2
H2O
FERMENTATION
LACTIC
ACID
OXYGEN
LIGHT REACTIONS
CO2
ELECTRON
CARRIERS
CALVIN CYCLE
DARK REACTIONS
C6H12O2
ALCOHOL
PYRUVATE
KREBS
ELECTRON
TRANSPORT
CHAIN
2
34
Are Plants Green?
In a word, sometimes.
Actually, the colors things appear are based
upon what colors they REFLECT, not
necessarily what they are.
Plants APPEAR GREEN because we see the
GREEN wavelengths of light they reflect.
It turns out that the green wavelengths of
light are the least useful for photosynthesis.
If green light was more useful, maybe plants
would be mostly blue, purple, red.
Pigments & Light Absorption
Pigments appear the color they do because they reflect certain
light to our eyes, which we then observe. The ones that aren’t
reflected are the ones they absorb.
List this table in your notes to remember the relationship between
what color a plant’s pigment is and what colors it absorbs.
Pigment
Their color is…
…because it reflects…
…therefore it
absorbs.
Chlorophyll a & b
Green
Green light
Blue & red light
Carotenoids
Red, orange, and
yellow
Red, orange, and
yellow light
Blue and green
light
Pigments
• You should know that leaves change color in the fall but why?
• If you were able to see inside of leaves there exists all pigments
that absorb light but their amounts change during the year.
• What does this say about photosynthesis throughout the year?
• Basically, leaves change color because the chlorophyll fades
away as the leaves age throughout the year.
• This is mainly because of the changing amount of sunlight and
available wavelengths of light.
• In the summer all wavelengths are available but in the fall, as
the Earth tilts, the wavelengths of light are fewer, reflective of
the ones that carotenoids absorb.
• This is an evolutionary adjustment of some plants.
• Plants, as a result, perform much less photosynthesis in the
winter than they do in the summer but do as long as they have
color.
Some supplements aim to increase the
efficiency of the KREBS cycles
Effective and responsible supplementation requires
the understanding of how these are metabolized
when your cells are performing at peak efficiency!
Process
These are:
CELLULAR RESPIRATION
EQUATIONS:
PHOTOSYNTEHSIS:
Process
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NET ATP