Ecosystem Recycling

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Ecosystem Recycling

• Chapter 9
• Section 9.2 and 9.3

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The Carbon Cycle

• Carbon is cycled through ecosystems mainly
  through the processes of photosynthesis and cell
  respiration.
• Photosynthesis converting light energy into
  chemical energy stored in organic compounds
  (carbohydrates)
• Formula 6 CO2 6 H2O sun
  C6H12O6 6 O2
• (energy) (glucose)
• Autotrophs (producers) carry out photosynthesis
  to make food
• Cellular Respiration- process of cells making
  energy (ATP) by breaking down organic compounds
• Formula C6H12O6 6 O2 6 CO2 6
  H2O ATP
• (Glucose) (energy)
• Heterotrophs (consumers) AND autotrophs
  (producers) use cell respiration to get energy
  from food
• What do you notice about the equations for these
  two processes???
• The products of one are the reactants for
  the other

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Photosynthesis to Respiration

• Heterotrophs eat other organisms, and autotrophs
  use the process of photosynthesis to create their
  own food.
• Once heterotrophs eat food, or autotrophs make
  food, cellular respiration takes place to break
  down food molecules and release energy in the
  form of ATP.
• ATP (adenosine triphosphate) chemical compound
  used by cells to store and release energy
• Cellular respiration provides the ATP that all
  cells need to support the activities of life.

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Photosynthesis takes place in the chloroplastThe
Structure of the Chloroplast

• Double outer membrane
• Thylakoids- inner
• membranes arranged as
• flattened sacs
• Grana- stacks of thylakoids
• Stroma- liquid solution
• surrounding grana

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Overview of Photosynthesis

• Photo light Synthesis to make
• Photosynthesis is a process which makes organic
  compounds (sugars) using sunlight
• Converts solar energy into chemical energy
  (energy stored in bonds of chemical compounds)
• There are 2 main steps to photosynthesis
• Light-Dependent (Light) Reactions
• Light-Independent (Dark) Reactions
• Animation

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Light Reactions

• Converts solar energy into energy used for the
• dark reactions.
• Requires the absorption of sunlight and water.
• Pigments like chlorophyll aid in the absorption
  of sunlight.
• Takes place in the thylakoid membranes of the
  chloroplast.
• Products include ATP and a molecule called NADPH.
• Serve as an energy source for the next step of
  the process.
• Oxygen is also produced as a by-product.
• Much of the oxygen is given off to the
  atmosphere.

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Light Independent Reactions (calvin cycle)

• Takes carbon from CO2 and puts it into organic
  compounds (process called carbon fixation).
• Requires CO2 from the atmosphere and ATP and
  NADPH as energy sources.
• ATP and NADPH are produced during the light
  reactions.
• Takes place in the stroma of the chloroplast.
• Produces glucose and other organic compounds.
• Broken down and used for energy.
• Stored for future energy needs.

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Factors Affecting Photosynthesis

• Amount of water
• Shortage of water can slow or even stop
  photosynthesis
• Plants in dry climates have waxy coating on
  leaves to prevent water loss.
• Temperature
• Enzymes of photosynthesis function best around
  35C.
• Temperatures above and below this range can slow
  photosynthesis.
• Intensity of Light
• Increase in light intensity increases rate of
  photosynthesis.
• At some point, plant reaches its maximum rate and
  cannot go any faster, no matter how much light is
  added.

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Cellular Respiration C6H12O6 6 O2
6 CO2 6 H2O energy(Glucose)
(ATP)

• Cell respiration is a process which breaks down
  organic compounds to release energy in the form
  of ATP.
• Both heterotrophs AND autotrophs perform cell
  respiration.
• 2 kinds of cell respiration
• Anaerobic (takes place in absence of oxygen)
• Aerobic (takes place in the presence of oxygen)

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Anaerobic Respiration

• Does NOT use oxygen and takes place in the
  cytosol.
• NOT efficient - produces only small amounts of
  ATP.
• Used by prokaryotes or simple eukaryotes
• Used by complex eukaryotes only as a backup to
  aerobic respiration.
• 2 different kinds of anaerobic respiration
• Lactic Acid Fermentation
• Alcoholic Fermentation
• Both produce by-products that are used by humans.

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Anaerobic Respiration (cont d.)

• Lactic Acid Fermentation
• Performed by bacteria.
• Produces lactic acid as a by-product.
• Lactic acid makes yogurt and cheese
• Lactic acid is made in your muscles during
  strenuous exercise and can cause soreness and
  cramps.
• Alcoholic Fermentation
• Performed by yeast.
• Produces ethyl alcohol and CO2 as by-products.
• Bread CO2 bubbles push the dough up and make it
  rise.
• Makes wine and beer - Yeast breaks down the
  sugars in grains or grapes producing CO2 and
  alcohol.
• Used to be used to make other carbonated
  beverages like root beer.

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Aerobic Respiration takes place in the
mitochondria of BOTH plants animals

• picture

• Double membrane (just like chloroplast)
• Matrix inner space
• Cristae folded inner membranes
• Why would you expect to have an abundance of
  mitochondria in your muscle cells?

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Aerobic Respiration

• Occurs in the presence of oxygen and takes place
  in the mitochondria.
• Much more efficient process than anaerobic
  respiration.
• Produces about 19 times more ATP than anaerobic
  respiration.
• Used by complex eukaryotes with large energy
  requirements.
• Carbon dioxide and water created as by-products.
• 2 main parts to aerobic respiration
• Krebs Cycle happens in matrix of mitochondria
• Takes the sugar and starts to break it down for
  the ETC
• Electron Transport Chain (ETC) happens in
  cristae of mitochondria
• Where most ATP is produced

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Lets wrap it up...

• Photosynthesis converts solar energy into
  chemical energy (autotrophs).
• Respiration makes ATP by breaking down organic
  compounds (either consumed or made depending on
  whether organism is an autotroph or heterotroph).
• Products of photosynthesis are the reactants of
  cell respiration and vice versa.
• Do all organisms carry out photosynthesis?
• Do all organisms carry out some sort of cellular
  respiration?