Transcript ENERGY AND LIVING THINGS

ENERGY AND LIVING
THINGS
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I. Energy flows between
organisms in living systems.
A.
Building molecules that store energy
1. Photosynthesis is the process by
which light energy is converted to
chemical energy.
2. Autotrophs are organisms able to
make their own energy. (Plants)
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3. Heterotrophs are organisms that are
UNABLE to make their own food and
have to consume their energy.
4. Cellular respiration is a metabolic
process similar to burning fuel. It
converts the food we eat into energy
our body can use.
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5. The word burn is often used to describe
how cells get energy from food.
6. The food that is taken in is converted to
energy that the cell can use. This molecule is
ATP. (adensine triphosphate)
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II. Photosynthesis
A.
Photosynthetic organisms use the energy
in sunlight
1. 6CO2 + 6H2O ---light----Carbon dioxide
2.
water
C6H12O6 + 6O2
Glucose
oxygen
Photosynthesis uses the energy of sunlight
to convert water and carbon dioxide into
high-energy sugars and oxygen.
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B. 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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B. The reactions of Photosynthesis
1. In plants and other photosynthetic
Eukaryotes, photosynthesis takes place
inside chloroplasts.
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C. 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. Energy and Cellular
Respiration
A. Chemical energy and food
1. How much energy is actually present
in food? - Lots!
2. One gram of glucose when burned
can release 3811 calories of heat!
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3. A calorie is the amount of energy needed
to raise the temperature of 1 gram of water 1
degree Celsius.
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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B. 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.
Glycolysis is the process in which one
molecule of glucose is broken in half,
producing two molecules of pyruvic acid.
(Also 2 ATP’s.)
2. Pyruvic acid marks the end of Glycolysis.
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3. The Pyruvic acid can take three
different paths.
1. Respiration –presence of
oxygen
2. Fermentation –No oxygen
3. 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
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2. This is a quick fix for the body BUT
lactic acid does have some down falls- pain.
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D. 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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E. 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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F. 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 and convert it for
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energy.
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THE END
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