1. Photosynthesis Chapter 8 Objectives Analyze and describe the work of scientists leading us to an explanation of how photosynthesis works. Look at the basic unit of chemical energy used by living things – (ATP) Homework Read 8-1 and 8-2 in your textbook. Do Now!!! What is photosynthesis? What are the reactants of photosynthesis? …products??

2. Autotrophs & Heterotrophs Autotrophs –Organisms which make their own food Heterotrophs –Organisms which can not make their own food

4. Adenosine Triphosphate

5. ATP and Energy

6. ATP and Glucose ATPGlucose Short TermLong Term Storage Transfers energy very quickly Takes longer to get energy out Can’t store energy very long. (breaks down to ADP and loses energy) Can store energy very well. 1 molecule of glucose can hold 90 times more energy than ATP.

7. Photosynthesis – “Energy Foundation” of Ecosystems Objective Describe the sources of the reactants of photosynthesis and trace the pathway to the products. Homework Web Quest will be collected and graded on Thursday. Do Now!!! What was Jan Van Helmont’s hypothesis? What was Jan Van Helmont’s experimental design? –What was the set up? –What did he measure??

8. Jan Van Helmont’s Experiment (1600’s) Wanted to find out if plants grew by taking nutrients out of soil. –After 5 years Plant Mass 75kg Soil Mass unchanged –Van Helmont accounts for the “Hydrate” carbohydrate

9. Joseph Priestley’s Experiment (Early 1700’s) Plants release oxygen

10. Jan Ingenhousz’s Experiment Showed that the effects in Priestley’s experiment only occurred when the plant was exposed to light.

11. Light- dependent reactions –Occurs in Thylakoid –Used H 2 O and light to produce ATP, NADPH, and O 2 –NADPH is an electron carrier Calvin cycle –Occurs in stroma – uses carbon dioxide, ATP, and NADPH to produce sugars