Photosynthesis

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Chapter 8

• Photosynthesis

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Ch. 8 Essential Questions

• What is energy?
• What is ATP?
• What is photosynthesis?
• What are light dark reactions?

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Question of the Day

• What does the Greek word chlorophyll stand for?
• Green Leaf

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8-1 Energy Life

• Autotrophs - produces own food energy
• Heterotrophs - obtain food from outside and get
  energy from it
• What is the energy?
• Glucose

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What Do Cells Use Energy For ?
ACTIVE TRANSPORT
Na - K PUMPEndocytosis Exocytosis
Images http//www.newtonswindow.com/problem-solvi
ng.htm http//www.lionden.com/cell_
animations.htm http//academic.brookl
yn.cuny.edu/biology/bio4fv/page/cell-movement.html
Animation from
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What Do Cells Use Energy For ?

• Movement
• Synthesis of biomolecules
• Reproduction

Meiosis http//www.tokyo-med.ac.jp/genet/anm/ Cil
ia http//www.sk.lung.ca/content.cfm?edit_realwor
dhwbreathe Replication http//www.beyondbooks.co
m/lif71/4c.asp Transcriptionhttp//www.wappingers
schools.org/RCK/staff/teacherhp/johnson/visualvoca
b/mRNA.gif Translation
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http//www.newtonswindow.com/problem-solving.htm
ONE SPECIAL KIND of NUCLEOTIDE is used by cells
to store and transport ENERGY
ATP
Image by Riedell
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CELLS USE ATP TO STORE and RELEASE ENERGY
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____ PHOSPHATE GROUPS

• 5-carbon sugar with 3 phos. 1 nitrogen

Adenosine triphosphate

• ATP

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ATP can change into ADP
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____ PHOSPHATE GROUPS

Adenosine diphosphate

• ADP __________________________

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http//www.cat.cc.md.us/gkaiser/biotutorials/ener
gy/adpan.html
ATP releases energy stored in a high
energy chemical bond by removing the phosphate
and becoming ADP

• ATP ? ____ __

ADP
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Cells ________ energy by adding the phosphate
back on to ADP to make ATP.
STORE

• The energy to do this comes from
• ____________ like _____________

FOODS
GLUCOSE
Its like recharging the battery !

ADP ___ ________ ? ___
ATP
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How Does ATP work?

• ATP is instant energy for the cell - like a
  charged battery
• ADP is a 1/2 charged battery
• Cells only have a very small amount of both
• Once made it is instantly burned/used by cell

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What Does ATP Power?

• ATP powers cell organelles and protein transport
• ATP when not in use is stored as Glucose

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8-2 Photosynthesis

• Photosynthesis needs 3 ingredients
• Light
• CO2
• H2O
• Light Pigments
• Pigments - light absorbing molecules
• Main pigment is Chlorophyll

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Two Types of Chlorophyll

• Chlorophyll A - absorbs violet and red light
  energy
• Chlorophyll B - absorbs blue, orange, yellow
  light energy

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Only color not absorbed is green - so its
reflected
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Photosynthesis Equation

• Photosynthesis - uses sunlight energy to turn
  water carbon dioxide into sugar air
• 6 CO2 6 H2O -gt C6H12O6 6 O2
• Oxygen and High Energy sugar are products

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Question of the Day

• What is the speed of light?
• 3x108 meters/sec

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Where the Magic Happens

• Inside a Chloroplast
• Thylakoids - photosystem sacs
• Grana - stacks of thylakoids
• Stroma - space outside thylakoids
• Also called mesophyll

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Photosynthesis Reactions

• Two reactions going on simultaneously
• Light Dependent (Light)
• Also called Photosystem I II, Electron
  Transport Chain
• Light Independent (Dark)
• Also Called Calvin Cycle
• Light Reaction Calvin Cycle happen at same time

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The Role of ATP NADPH

• NADPH ATP are energy carrier molecules
• NADPH ATP get broken down into 1/2 charged
  NADP ADP
• Electrons move b/c light hits thylakoid to charge
  up NADPH ATP

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Light Dependent Reactions

• All occur Chloroplast
• Photosystem I II
• Light absorbed by chlorophyll creates energy
• Enough to make NADPH ATP
• Light excites electrons to move down Electron
  Transport Chain (ETC)

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More Light Reactions

• Electron Transport Chain -
• Moves electron from Photosystems I II from
  sunlight energy
• Electron moverment creates ATP NADPH

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Calvin Cycle

• Light Independent Reactions
• Four Steps
• 1. CO2 enters cycle
• 2. ATP NADPH (from ETC) make 3-carbon
• Pyruvate (3-Carbon Sugar)
• 3. Add More ATP NADPH to make 6-carbon sugar
• Glucose
• 4. Leftover carbons ADP/NADP get recycled

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Factors Affecting Photosynthesis

• Water - shortage or abundance
• Temperature - enzymes need 32-750 weather
• Light intensity - best at equator
• Weather - sun/shade wind all affect photo.

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Game Time

• Using Paper Template Textbook, draw all
  Reactions Light- Dependent Independent