Cellular Respiration Mrs' Schenfields Life Science

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Cellular RespirationMrs. SchenfieldsLife
Science
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Cellular Respiration Overview

• Transformation of chemical energy in food into
  chemical energy cells can use ATP
• These reactions proceed the same way in plants
  and animals. Process is called cellular
  respiration
• Overall Reaction
• C6H12O6 6O2 ? 6CO2 6H2O

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Cellular Respiration Overview

• Breakdown of glucose begins in the cytoplasm
  the liquid part called cytosol
• Sugar is the most common energy source (some
  cells use fats and proteins
• Requires many enzymes
• The enzymes disassembly line takes the sugar
  apart, periodically releasing small amounts of
  energy that fuel the cell

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Types of Cellular Respiration

• At this point life diverges into two forms and
  two pathways
• Anaerobic cellular respiration (fermentation)
• Aerobic cellular respiration

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Cellular Respiration Reactions

• Glycolysis
• Series of reactions which break the 6-carbon
  glucose molecule down into two 3-carbon molecules
  called pyruvate
• Process is an ancient one-all organisms from
  simple bacteria to humans perform it the same way
• Yields 2 ATP molecules for every one glucose
  molecule broken down

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Anaerobic Cellular Respiration

• Some organisms thrive in environments with little
  or no oxygen
• Marshes, bogs, gut of animals, sewage treatment
  ponds
• No oxygen used anaerobic
• Results in no more ATP, final steps in these
  pathways serve ONLY to regenerate NAD so it can
  return to pick up more electrons and hydrogens in
  glycolysis.
• End products such as ethanol and CO2 (single cell
  fungi (yeast) in beer/bread) or lactic acid
  (muscle cells)

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Anaerobic Cellular Respiration

• Alcoholic Fermentation-some bacteria and fungi
  use this as their only source of energy.
• Yeast in bread dough uses this and produces
  carbon dioxide that gets trapped in the dough and
  causes bread to rise.
• Yeast is a leavening agent and is mentioned in
  the Bible.
• (enzymes)
• Sugar carbon dioxide 2-3 ATP

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Anaerobic Cellular Respiration

• Lactic Acid Fermentation-produced and released by
  bacteria in yogurt, buttermilk, and sauerkraut.
• If, when you exercise, you are not able to supply
  enough oxygen to muscle cells they will switch to
  anaerobic respiration which produces lactic acid.
• The build of lactic acid causes soreness in
  muscles.
• Not as efficient as aerobic cellular respiration

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Aerobic Cellular Respiration

• Oxygen requiredaerobic
• Mitochondria perform the recharging of ATP
  molecules by transferring energy from the sugar
  molecules to ATP.
• (enzymes)
• Sugar oxygen carbon dioxide water
  26-28 ATP
• The cells of many organisms and your body perform
  this type of cellular respiration.

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Energy Tally

• 36 ATP for aerobic vs. 2 ATP for anaerobic
• Glycolysis 2 ATP
• Krebs 2 ATP
• Electron Transport 32 ATP
• 36 ATP
• Anaerobic organisms cant be too energetic but
  are important for global recycling of carbon

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