Cellular Respiration

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Cellular Respiration

• Chapter 6

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Energy Flow and Chemical Cyclingin the Biosphere

• Fuel molecules in food
• represent solar energy
• traced back to the sun
• Animals depend on plants
• to convert solar energy to chemical energy
• In form of sugars and other organic molecules

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Producers and Consumers

• Autotrophs
• Producers
• Make own organic matter from inorganic nutrients
• Photosynthesis
• Heterotrophs
• Consumers
• Cannot make organic molecules from inorganic ones
• Cellular respiration

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Chemical Cycling between Photosynthesis and
Cellular Respiration

• The ingredients for photosynthesis
• CO2 obtained from the air
• H2O obtained from the damp soil
• Chloroplasts rearrange the atoms of these
  ingredients
• produce sugars (glucose) and other organic
  molecules
• Oxygen gas a by-product of photosynthesis

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Cellular Respiration

• Release of energy from molecules accompanied by
  the use of this energy to synthesize ATP
  molecules
• Metabolic pathway
• Main method that chemical energy is harvested
  from food and converted to ATP
• Aerobic
• Requires oxygen and gives off carbon dioxide
• Oxidation reduction reaction
• Glucose oxidized
• Oxygen reduced

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Redox Reaction (O-R)

• Chemical reaction that transfers electrons from
  one substance to another
• Oxidation
• Loss of electrons
• Reduction
• Acceptance of electrons

Oxidation
Reduction
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ATP

• Adenosine triphosphate (ATP)
• Nucleotide with the base adenine and the sugar
  ribose
• Main energy carrier in cells
• Formed during reactions that breakdown organic
  compounds to CO2 and water
• Requires ample oxygen
• Occurs within the mitochondrion
• Hydrolyzes phosphates to release energy
• form adenosine diphosphate (ADP)

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Cellular respiration

• Cellular respiration and breathing are closely
  related
• Cellular respiration requires a cell to exchange
  gases with its surroundings
• Breathing exchanges these gases between blood and
  outside air

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Where Is the Energy in Food?

• The process of aerobic respiration requires
  oxygen and carbohydrates
• C6H12O6 6 O2 ? 6 CO2 6 H2O energy
• The products are carbon dioxide, water, and
  energy (heat or ATP)

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The Players.

• Glucose
• NAD
• FAD

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Where Is the Energy in Food?

• Cellular respiration takes place in three stages
• Glycolysis
• Citric Acid Cycle
• Electron transport

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1. Glycolysis

• Occurs in the cytoplasm
• Glucose split into 2 molecules
• Pyruvate
• Does not require oxygen to generate ATP
• Then, enters aerobic or anaerobic reactions

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2. Citric Acid Cycle

• Krebs Cycle
• occurs within the mitochondrion
• Converts pyruvic acid acetic acid Acetyl CoA
• electrons passed to an electron transport chain
  in order to power the production of ATP

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3. Electron transport chain

• Uses electrons to make ATP
• NAD FAD
• Carry electrons from the cytoplasm or the
  mitochondrial matrix and carry them to the
  mitochondria
• NADH and FADH2 transfer their electrons to a
  series of membrane-associated molecules

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Fermentation

• Occurs when O2 is not available
• Animal cells convert pyruvate to lactate
• Other organisms convert pyruvate to alcohol and
  CO2