1. Chapter 4 Cells and Energy
ATP and Photosynthesis

2. Work Is done when anything is moved
Life processes rearrange molecules, ions, and atoms
Requires energy

3. Energy Is the ability to do work Comes from food
Food is broken down into small molecules that can enter cells
Cells break down molecules to release the energy

4. Energy from molecules Is not all used at one time
Used to balance supply and demand
Energy not used right away is stored in a molecule called ATP
ATP releases the energy when the cell needs it
Cells die without ATP

5. ATP Adenosine triphosphate Sugar (ribose) Adenine 3 phosphate groups
Energy is stored in the phosphate-phosphate bonds
When a phosphate is removed, energy is released to the cell
ADP is left

6. ADP Adenosine diphosphate Sugar (ribose) Adenine 2 phosphate groups
Is recycled by adding another phosphate to store energy
Putting another phosphate on ADP converts it back to ATP

7. ATP / ADP Cycle

8. Energy cycle ADP + P + energy = ATP ATP
Energy available for work is free energy
Energy stored in molecules is potential energy
ATP is the energy link between energy-using and energy-releasing reactions

9. Autotrophs Trap energy from sunlight for photosynthesis
Most plants are green because of chlorophyll (green pigment)
Chlorophyll reflects green light
Energy from sun is trapped inside thylakoid membrane of chloroplast

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11. Photosynthesis
2 groups of reactions: light reactions and Calvin cycle (dark reactions)
Light reactions
Light converted to chemical energy
Photo part
Split water and give hydrogen to Calvin cycle
Calvin cycle
Forms sugar from CO2 and H (from water)
Synthesis part

12. Light reactions Electrons in chlorophyll absorb light energy
Electrons leave chlorophyll and are passed through electron transport chain
Extra energy is stored as ATP
Water is split into O2 and H+ (photolysis)
H + electron picked up by NADP+ (electron carrier)
O2 given off as waste

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Photolysis
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14. Calvin Cycle Enzyme adds C from CO2 to a 5-carbon molecule
C is not fixed to an organic molecule (carbon fixation-coverts gaseous CO2 to a useable form for living things: sugars, starch, cellulose)
Called dark reactions because light does not have to be available for fixation

15. Section 9.2 Summary – pages 225-230
(CO2)
(CO2)
The Calvin Cycle
(Unstable intermediate)
(RuPB)
ADP +
ATP
ATP
ADP +
NADPH
NADP+
(PGAL)
(PGAL)
(PGAL)
(Sugars and other carbohydrates)
Section 9.2 Summary – pages

16. Life without light Some organisms are chemosynthetic (bacteria)
Obtain energy by converting inorganic compounds into useable forms
Usually final participants in decomposition processes