Chapters 8

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Chapters 8 9

• Photosynthesis and Cellular Respiration

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I. Energy the ability to do work

• Cells work growth, repair, active transport, and
  reproduction
• Organisms get energy from food
• How do organisms get food?
• 1. Make it
• 2. Eat it

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II. Autotrophs Heterotrophs

• Autotrophs make their own food (also called
  producers)
• 1. Most are photosynthetic
• - use sunlight as an energy source
• - examples plants algae

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• 2. A few are chemosynthetic
• - use inorganic compounds as an energy
  source
• - example bacteria deep in ocean

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• B. Heterotrophs cannot make their own food
  (also called consumers)
• 1. Eat autotrophs or other heterotrophs
• 2. Examples animals, fungi

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III. ATP

• Cells store energy in the form of a molecule
  called adenosine triphosphate (ATP)
• Parts of ATP
• 1. Adenine a nucleotide
• 2. Ribose 5 carbon sugar
• 3. 3 phosphate groups (PO4)

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Adenosine
Bonds broken to release energy
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• - adenosinePO4AMP
• (adenosine monophosphate)
• - adenosinePO4PO4ADP
• (adenosine diphosphate)
• adenosinePO4PO4PO4ATP(adenosine triphosphate)

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• ATP Cycle
• 1. Food energy is used to make ATP in
  cellular respiration
• 2. ATP is broken down to release energy
  for the cell

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ATP
Energy for cell
Food energy
ADP
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IV. Photosynthesis

• Photosynthesis occurs in chloroplasts (organelles
  inside plants)

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• Overview of Photosynthesis
• 1. Uses light as the source of energy
• 2. Makes glucose (C6H12O6)
• 3. Uses water and carbon dioxide as
  reactants

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• 4. Chlorophyll is the catalyst
• 5. Gives off oxygen as a by-product
• 6. Equation
• 6CO2 6H20
• C6H12O6 6O2

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• Photosynthetic pigments
• 1. Chlorophyll primary pigment appears
  green

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• Carotenoids secondary pigments can appear
  yellow, red, or orange

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• Chloroplast Structure
• 1. Double membrane (innerfolded,
  outersmooth)

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• grana stacks of thylakoids
• thylakoid 1 disc
• stroma gel-like material between thylakoids

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• 2. Light dependent reactions occur in the
  thylakoids
• 3. Light independent reactions (Calvin
  Cycle) occur in the stroma

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• Summary of Photosynthesis
• 1. Light dependent reactions a. light
  causes electrons in chlorophyll to become
  excited
• b. light energy is also used to split
  water

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• c. oxygen is released as a by-product
• d. hydrogen is passed to the Calvin Cycle
• e. ATP is made - this is used as an energy
  source for the Calvin Cycle

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• 2. The light independent reactions (also
  called the Calvin Cycle)
• a. CO2 from the air combines with the
  hydrogen from the light dependent reactions
  to make sugar (C6H12O6)
• b. ATP made in light dependent
  reactions is used as an energy source

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• 3. Summary equation
• 6CO2 6H20 C6H12O6 6O2
• - light is required as an energy
  source
• - chlorophyll is required as a catalyst

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V. Cellular Respiration

• Respiration occurs in mitochondria (organelles in
  all eukaryotic cells)

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• Overview of Respiration
• 1. Usually uses oxygen
• 2. Breaks down glucose into energy

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• 3. Gives off carbon dioxide and
  water as by-products
• 4. Equation
• C6H12O6 6O2
• 6CO2 6H20 energy

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• C. Steps of Respiration
• 1. Glyolysis glucose is converted to
  pyruvic acid occurs in the cytoplasm
• a. 2 molecules of ATP required
• b. oxygen not required
• c. glucose (6 carbons) is broken down
  into 2 molecules of pyruvic acid (3
  carbons)

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• d. 4 molecules of ATP released
• e. An energy-rich molecule called NADH is
  made this will be used later to make ATP

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• 2. Aerobic respiration occurs if oxygen is
  present
• a. pyruvic acid is broken down into acetyl
  Coenzyme A
• b. acetyl Coenzyme A enters the Krebs Cycle

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• c. In the Krebs Cycle
• 1. CO2 is released
• 2. 2 molecules of ATP are produced
• 3. Energy rich molecules of NADH and
  FADH2 are produced these will be
  used later to make ATP

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• d. The electron transport chain
• 1. Electrons from NADH and FADH2 are
  passed along the electron transport chain
• 2. Energy from these electrons is used
  to make 32 ATP

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• 3. Hydrogen from NADH and FADH2 is
  combined with oxygen to produce H2O

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• 3. Anaerobic respiration occurs if oxygen is
  not present
• a. 2 types
• 1. Alcoholic fermentation
• 2. Lactic acid fermentation

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• b. Alcoholic fermentation
• 1. Pyruvic acid is converted to
  carbon dioxide and alcohol
• 2. Equation
• pyruvic acid NADH
• alcohol CO2 NAD

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• 3. Used to make bread, wine, beer, ethanol

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• c. Lactic acid fermentation
• 1. Pyruvic acid is converted to
  lactic acid
• 2. Equation
• pyruvic acid NADH
• lactic acid NAD

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• Occurs in animal cells
• - after strenuous exercise, there is a
  shortage of oxygen going to the
  muscles
• - a build-up of lactic acid causes muscle
  fatigue and soreness