Intro to Photosynthesis

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Intro to Photosynthesis
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Introduction to Cell Energy

• All Life needs energy to carry out life
  processes.
• Autotrophs(Producers) Make their own food
• Heterotrophs (Consumers) eat other living
  organisms for food.

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Lifes Currency

• Lifes energy currency ATP (adenosine
  triphosphate).
• Energy is released when the phosphate bonds are
  broken by water.
• ATPH2O ADP Pi
• ADP P energy ? H2O ATP

Breaking ATP
Making ATP
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A Closer Look at ATP

• ATP is stored energy in the cell, used for
  metabolism.
• Exergonic Reactions Release Energy
• ATP ADP
• Endergonic ReactionsAbsorbs Energy
• ADP ATP

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The ADP/ATP molecule is like a battery that
stores energy
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ATP at Work
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Now you know the basics..

• What is photosynthesis?
• Plants use this process to store energy from the
  sun as chemical energy.
• The new chemical energy is usually stored in the
  form of glucose.
• Endergonic reaction
• 6CO2 6H2O energy(sun) gt C6H12O6 6O2
• Carbon dioxide water energy gt glucose
  oxygen

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PhotosynthesisStep one
Step 1
Chemical Reaction
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How it works

• Photosynthesis requires water, carbon dioxide,
  and chlorophyll, a molecule in chloroplasts.
• The plants principal pigment is chlorophyll
  (MAKES PLANTS GREEN)
• Two types
• Chlorophyll a- absorbs violet and red
• Chlorophyll b- absorbs blue and red light
• Plants also have Carotenoids and xanthophyll
  give plants the yellow, orange, and red color in
  autumn.
• pigments- light absorbing molecules used to
  gather the suns energy

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Absorption of Light by Chlorophyll a and
Chlorophyll b
Chlorophyll b
Chlorophyll a
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Thylakoids- saclike photosynthetic membranes,
contain photosystems (photosystems are clusters
of pigment and protein that absorb light
energy) Stroma- space outside the thylakoid
membranes Granum- is a stack of thylakoids
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Two main reactions of Photosynthesis

• Light Dependent reactions
• Occurs when light hits the thylakoid membranes
  (green discs).
• Light independent-reactions Calvin Cycle
• Occurs in the stroma (space between the grana) of
  the chloroplasts. This is where the sugars are
  made (Glucose). This is the synthesis part of
  photosynthesis.

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5 steps to Photosynthesis

• 1). Sunlight activates chlorophyll
• 2). Energy from activated chlorophyll splits
  water
• 3).O2 is released from H2O
• 4). Energy and hydrogen combine with CO2
• 5). Sugar is produced

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Steps One, Two, Three
Light Reactions

• Sunlight excites electrons in chlorophyll, the
  electrons gain a great deal of energy.
• These high-energy electrons require a special
  carrier. What is this special carrier? NADP
• The light dependent reactions produce oxygen gas
  from water and convert ADP and NADP into the
  energy carriers ATP and NADPH.

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H2O
O2
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Step 4 5
Calvin Cycle

• Plant use the ATP and NADPH from the
  light-dependent reactions to produce high energy
  sugars. C6H12O6.
• Use CO2 from the atmosphere
• Release NADP and ADP back into the light
  reactions.

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H2O
O2