1. Chapter 8: Photosynthesis

2. Section 8-1 Energy and Life

3. Energy Energy – the ability to do work.
Necessary for cell survival.
ATP (adenosine triphosphate) – chemical compound that cells use to quickly transfer energy

4. Chemical Energy and ATP
ATP is like a rechargeable chemical battery
Energy is stored in bonds between phosphates.

5. To “charge up the battery,” the cell uses energy to attach a phosphate to an ADP (adenosine diphosphate)
ADP + phosphate becomes an ATP
The energy used to make the bond is now stored in the bond
Energy Used

6. To get the energy out of the ATP to use for something, the last phosphate is broken off.
ATP turns back into ADP
Energy is released from the broken bond
Energy Used

7. Autotrophs and Heterotrophs
SO… Where do living things get energy?
FOOD
Food for a cell = glucose.
SO… How do living things get food?
Different ways of obtaining food:
Autotrophs – organisms that make their own food through photosynthesis (AKA: producer)
Examples: plants, algae, certain bacteria
Heterotrophs – organisms that consume or eat food (AKA: consumer)
Examples: animals, fungi, some bacteria, some protists

8. Section 8-2 Photosynthesis: An Overview

9. The Photosynthesis Equation
Photosynthesis uses the energy of sunlight to synthesize (assemble) glucose.
  ____ ____ sunlight C6H12O ____
(glucose)

10. The Photosynthesis Equation
  _CO _H2O sunlight C6H12O _O2
(carbon dioxide) (water) (glucose) (oxygen)

11. The Photosynthesis Equation
  CO H2O sunlight C6H12O O2
(carbon dioxide) (water) (glucose) (oxygen)

12. Section 8-3 The Reactions of Photosynthesis

13. Inside a Chloroplast
Photosynthesis takes place within chloroplasts.

14. Reactions of Photosynthesis
Light Dependent Reactions or Light Reactions:
Chlorophyll captures sunlight energy
Uses it to “charge up” ADP and similar “chemical batteries”
Charged “chemical batteries” carry the energy to the Calvin Cycle

15. Reactions of Photosynthesis
Calvin Cycle or Light-Independent Reactions or Dark Reactions:
ATP releases the energy, becomes ADP which recycles to the Light Reactions
Calvin Cycle uses that released energy to synthesize (make) glucose

16. Factors Affecting Photosynthesis
Temperature – photosynthesis uses enzymes, which extreme temperatures will slow or denature. Occurs best between 0C and 35C.
Water – photosynthesis requires water so low water availability would slow down the rate of photosynthesis
Light – more light speeds up the rate of photosynthesis, but there is a maximum photosynthesis speed.