Transcript Photosynthesis and Cellular Respiration

Photosynthesis and
Cellular Respiration
How do cells obtain organic
compounds for energy?
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Heterotrophs: Cannot make their own food
Autotrophs: Can make their own food
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Photoautotrophs: Use energy from the sun
(photosynthesis) to produce organic compounds
(glucose)
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Plants, algae and some bacteria
Chemoautotrophs: Use energy stored in inorganic
compounds (chemosynthesis) to produce organic
compounds
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Some bacteria found at the hydrothermal vents of the seafloor
Photosynthesis
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Method of converting light energy from the sun
into chemical energy that cells can use
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Divided into the light-dependent and light-independent
reactions
Photosynthesis takes place in chloroplasts
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The parts of a chloroplast are as follows:
 Thylakoids- disk-shaped structures that contain the
pigment chlorophyll (absorbs the sunlight)
 Grana- A stack of thylakoids
 Stroma- Liquid between grana
Draw a Chloroplast
Overall Photosynthesis Reaction
6CO2 + 6 H2O + light energy → C6H12O6 + 6O2
•On
the left of the arrow are the reactants (the
components that “react” together).
•On the right of the arrow are the products.
•Identify how a plant obtains the reactants.
Light-dependent Reactions
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Chlorophyll (in thylakoids) absorbs the light
energy
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Plants have 2 types: Chlorophyll A and
Chlorophyll B
Water molecules are split apart producing H and
O2
Electrons flow throughout the thylakoid
membrane (electron transport chain)
Energy compounds ATP and NADPH are
produced
Light-independent Reactions (Dark
Reactions)
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Occur in the stroma
ATP and NADPH from the light reactions are
used to fuel the break down of CO2 and the
reassembling of the atoms to produce glucose.
This reassembling is called “carbon fixation”.
Carbon fixation occurs in a series of reactions
called the Calvin Cycle.
Photosynthesis Practice
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You and a partner need:
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6 orange circles = C
12 blue triangles = H
18 pink squares = O
1 large green oval = thylakoid
1 small green rectangle = ATP
1 small green rectangle = NADPH
1 yellow circle = sun 
Getting energy out of food
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Plants and animals both use glucose from
photosynthesis for cell fuel.
Glucose (or other carbs), proteins, and fats are
not a form of energy that our cells can use.
Cellular respiration converts glucose into a
usable energy form (ATP) for cells.
Cellular Respiration Overview
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The reactions of cellular respiration occur the
same way in plants and animals.
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Overall Reaction:
C6H12O6 + 6O2 → 6CO2 + 6H2O
How is this compared to the photosynthesis
equation?
Glycolysis
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Glycolysis is the first process of cellular
respiration.
It occurs in the cytosol.
Glucose (C6H12O6) is partially broken down to
produce 2 pyruvate (C3H3O3) compounds
This process yields 2 ATP and 2 NADH for every
glucose molecule.
Aerobic Cellular Respiration
Oxygen required=aerobic
 Aerobic respiration follows glycolysis.
 It occurs in the mitochondria.
 There are 2 main parts to aerobic
respiration:
– Kreb’s Cycle
– Electron Transport Chain
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Kreb’s Cycle
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Completes the breakdown of glucose
– Takes the 2 pyruvate (C3H3O3) and
completely breaks them down.
– The carbon and oxygen atoms of pyruvates
end up in CO2 and H2O
 This
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is where the CO2 that we exhale is produced!
3 NADH and 1 FADH2 and 2 ATP get
produced
Electron Transport Chain
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Here is where most of the energy is produced!
Electron flow ultimately produces 32 ATP!
The oxygen that we inhale is the electron
acceptor at the end of the ETC. This
acceptance of electrons is what produces the
ATP.
Photosynthesis
Cellular Respiration
Cellular Respiration Practice
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You and a partner need:
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5 NADH (green)
4 ATP (red)
1 FADH2 (green)
1 mitochondria (blue)
Anaerobic Cellular Respiration
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Some organisms (some bacteria) thrive in environments
with little or no oxygen
No oxygen used= anaerobic
Anaerobic organisms experience anaerobic cellular
respiration after glycolysis.
This produces NO ATP!
Depending on the type of cell, the end products of this
are alcohol or lactic acid.
Energy Tally
Aerobic
Anaerobic
Glycolysis
Kreb’s Cycle
Electron Transport Chain
Total ATP per glucose
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Anaerobic organisms can’t be too energetic but
are important for global recycling of carbon