The Calvin Cycle Basics

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The Calvin Cycle Basics
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• Dr. Calvin utilized carbon-14 isotopes as
  radioactive tracers to reveal the chemical
  processes of photosynthesis.
• The Calvin Cycle illustrates how plants turn
  carbon dioxide and water into sugar.
• The Calvin Cycle is a metabolic pathway found
  in the stroma of the chloroplast in which
  inorganic carbon is fixed into an organic form.

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• Dr. Calvin was also named Mr. Photosynthesis
  in 1961 by Time Magazine.
• Dr. Calvin has long since earned the
  title "Mr. Photosynthesis." Shortly after World
  War II, he began to use radioactive tracers,
  particularly carbon-14, and other recently
  developed tools to find out what happens to
  carbon dioxide when it tangles with chlorophyll
  in a living green plant cell.
• Step by painful step, Calvin and
  his large
  group of helpers
  followed CO2, tagged with
  
  carbon-14, through the intricate
  
  photosynthetic processes that start
  when green
  leaves are exposed
  to sunlight.

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• Green algae (chlorella), grown in continuous
  cultures, were placed in the "lollipop" with the
  light shining on them. Carbon-14 labeled CO2 was
  injected into the stream of nonradioactive CO2
  for a suitable period, at the end of which the
  algae were killed.
• The compounds into which the radioactive
  carbon had entered were analyzed by paper
  chromatography.

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• The Calvin cycle fixes carbon dioxide and the
  adds energy and hydrogen ions to the resulting
  molecules to yield a three carbon phosphate sugar
  called PGAL or G3P.
• The fixed (organic) carbon of PGAL is used to
  produce the variety of organic compounds of
  living organisms. It is used to keep the cycle
  going, and is used to produce carbohydrates such
  as glucose.

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Heres What Happens
This is called carboxylation. Carbon is fixed
here!
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twelve 3-C PGALs
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• 
  from 3
• 6) Two 3C PGALs form fructose then glucose.

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• PGAL (G3P) and other sugar phosphates from the
  Calvin cycle are food for plants.
• PGAL molecules can be used to supply energy and
  carbon skeletons for metabolism in the plant.
• Some sugar phosphates are made into lipids, amino
  acids then protein. This can occur in the
  chloroplast.

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• Humans and other animals consume plants and
  thus use the material from photosynthesis for
  building protein, as well as a source of sugars
  and energy.