Cellular Respiration

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Cellular Respiration

• General Biology I Lab
• IRSC

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What is cellular respiration?

• We eat to obtain energy
• Our cells convert the energy that is trapped in
  the bonds of an organic molecule (i.e. glucose)
  and converts it to energy the cell can use (ATP)
• Everything living thing (whether unicellular or
  multicellular) needs to go through respiration to
  obtain ATP
• What do cells need energy for?

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• Aerobic Cellular Respiration Uses Oxygen
• C6H12O6 6 O2 ? 6 CO2 6 H2O energy (ATP)
• 4 steps to cellular respiration
• Glycolysis happens in cytoplasm
• Pyruvate oxidation happens in mitochondria in
  eukaryotes
• Citric Acid Cycle happens in mitochondria in
  eukaryotes
• Oxidative phosphorylation via electron transport
  chain happens on inner mitochondrial membrane
  in eukaryotes

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What happens without oxygen?Fermentation

• Anaerobic cellular respiration
• C6H12O6 ? 2 C2H5OH 2 CO2 2 ATP 2 H2O
• Fermentation
• 2 parts
• Glycolysis happens in cytoplasm
• Just like in aerobic respiration, this is where
  the 2 ATP are produced
• Fermentation happens in cytoplasm, also
• Nothing happens in the mitochondria because there
  is no oxygen
• Electron carriers that were reduced in glycolysis
  are oxidized in fermentation so that they can
  return to glycolysis process

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• Ethanol is produced when yeast ferments
• Lactic Acid is produced by mammalian muscle cells
  when not enough oxygen is available
• These organic molecules are left over because
  there is no oxygen so the glucose molecule is not
  completely oxidized
• Glycolysis is the only energy harvesting step
  that happens
• These organic molecules still have energy

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Aerobic VS. Anaerobic
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Cellular Respiration experiment

• We will be using germinating and non-germinating
  peas
• Germinating peas are alive and growing, cells
  need usable energy
• Remember plants go through Photosynthesis AND
  cellular respiration
• Non-germinating peas have been freeze dried
• Follow directions in packet
• KOH absorbs CO2
• Oxygen consumption will be measured
• How will we do this?

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We use peas instead of grasshoppers
http//www.phschool.com/science/biology_place/labb
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Fermentation

• For this experiment, we use yeast
• Follow directions in packet
• Mix yeast with sugar solution
• Tube 1 Glucose
• Tube 2 Fructose
• Tube 3 Sucrose
• Tube 4 distilled water (control)
• Place in fermentation tube invert to get rid of
  air
• Place all tubes in incubator
• Measure CO2 - release of carbon dioxide
  indicates that fermentation has occurred
• Gas will collect at top of tube

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Yeast can use all 3 sugars