Transcript PHOTOSYNTHESIS AND GLYCOLYSIS

PHOTOSYNTHESIS AND
GLYCOLYSIS
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I. Energy and Life
A. Autotrophs and Heterotrophs
1. Plants and some other types of organisms
are able to use light energy from the sun to
produce food.
2. Organisms such as plants, which make
their own food, are called autotrophs.
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3. Other organisms, such as animals
need to take in food are called
heterotrophs.
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B. Chemical Energy and ATP
1. Adenosine Triphosphate ATP is food
converted into what the cells can use as
energy.
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II. Photosynthesis and overview
A. Investigating Photosynthesis
1. In 1643, Van Helmont conducted an
experiment and determined that trees
gain most of their mass from water.
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2. In 1771, Jospeh
Prietly found that
plants release a
substance that keeps a
candle burring. A
substance that we now
know is oxygen.
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3. In 1779, Jan
Ingenhousz found
out that aquatic
plants produce
oxygen bubbles in
the light but not the
dark. He concluded
that plants need
sunlight to produce
oxygen.
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B. Photosynthesis equation
1. 6CO2 + 6H2O ---light----Carbon dioxide water
C6H12O6 + 6O2
Glucose
oxygen
2. Photosynthesis uses the energy of
sunlight to convert water and carbon dioxide
into high-energy sugars and oxygen.
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C. Light and pigments
1. In addition to water and carbon
dioxide, photosynthesis requires light and
chlorophyll, a molecule in chloroplast.
2. Plants gather the sun’s energy with
light absorbing molecules called pigments.
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3. The plants primary pigment is
chlorophyll.
4. There are two main types of chlorophyll
a and b.
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D. The reactions of Photosynthesis
1.
In plants and other photosynthetic
Eukaryotes, photosynthesis takes place inside
chloroplasts.
2.
Portions in the thyakoid membrane
organize chlorophyll and other pigments into
clusters known as photosystems.
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E. Light Dependent reactions
1.
Light dependent reactions require light.
2.
The light dependent reactions produce oxygen gas
and convert ADP and NADP into the energy carriers
ATP and NADPH.
3.
The Calvin cycle uses ATP and NADPH from the
light dependent reactions to produce high-energy
sugars.
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F. Factors affecting photosynthesis
1. Many factors affect the rate at which
photosynthesis occurs.
2. Shortage of water can slow or even
stop photosynthesis.
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3. Plants that live in dry climate have a waxy
coating on their leaves to reduce water loss.
4. Temperature above or below 0-35 C can
slow down the rate of photosynthesis.
5. The intensity of light also affects the rate at
which photosynthesis occurs.
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6.Increased light activity increases
photosynthesis.
7. Decreased light activity decreases
photosynthesis
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III. Cellular Respiration
A. Chemical energy and food
1. How much energy is actually present in
food? - Lots!
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2. One gram of glucose when burned
can release 3811 calories of heat!
3. A calorie is the amount of energy needed
to raise the temperature of 1 gram of water
1 degree Celsius.
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4. Cells don’t “burn” glucose; instead
they gradually release the energy from
glucose and other food compounds.
5. Glycolysis releases only a small
amount of energy.
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6. If oxygen is present, Glycolysis leads
to two other pathways that release a
great deal of energy.
7. If oxygen is NOT present, Glycolysis
goes to a different path.
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A. Overview of cellular respiration
1.
Cellular respiration is the process that
releases energy by breaking down glucose
and other food molecules in the presence of
oxygen.
2. 6O2 + C6H12O6 -------- 6CO2 + 6H2O + energy
Oxygen
Glucose
Carbon dioxide
water
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C. Glycolysis
1.
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Glycolysis is the process in which one
molecule of glucose is broken in half,
producing two molecules of pyruvic acid.
(Also 2 ATP’s.)
Pyruvic acid marks the end of Glycolysis.
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3. The pyruvic acid can take three
different paths.
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Respiration –presence of oxygen
Fermentation –No oxygen
Lactic acid- no oxygen
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D. Anaerobic respiration (cellular respiration
WITHOUT oxygen)
1.
In an animal cell if the cell is under stress or if
there is insufficient amount of oxygen the body will
convert the pyruvic acid into quick energy – lactic
acid.
2. This is a quick fix for the body BUT lactic acid
does have some down falls- pain.
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E. Fermentation (occurs in plants, without
oxygen)
1. Fermentation releases energy from food
molecules by producing ATP in the absence of
oxygen.
2.
Yeasts and a few other microorganisms
use alcoholic fermentation, forming ethyl
alcohol and carbon dioxide as waste.
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F. Krebs cycle – cellular respiration WITH
oxygen.
1.
During the Kreb cycle, pyruvic acid is
broken down into carbon dioxide in a series
of energy extracting reactions.
2.
The Kreb cycle is where most of the ATP is
made.
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3. The Kreb cycle occurs inside the
mitochondria.
4. In the Kreb cycle the total ATP that is
made is 36 or 38 ATP for 1 glucose molecule.
5. Muscle cells have the capabilities of
making 38 ATP. Why do you think?
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G. Energy and exercise
1.
When quick energy is needed the body will use
what ATP is there and ready to go. If more ATP is
needed then the body starts to produce lactic acid.
2. When long-term energy is needed the body will
resort to stored energy. The body has the time to
use the stored energy and convert it for energy.
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THE END
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