1. Energy of Life

2. Energy the ability to do work Where does your energy come from?
Autotrophs - use energy from the sun to produce food.
Heterotroph - get energy from the food they eat
Forms of Energy
light
heat
electricity

3. Energy Compounds Adenosine Triphosphate or ATP 3 Phosphate Groups
Energy powers active transport, protein synthesis, & muscle contractions

4. break off a phosphate, energy is released
Storing Energy
ATP = ADP + 1 Phosphate
fully charged battery
Releasing Energy
break off a phosphate, energy is released

5. Photosynthesis Introduction

6. Photosynthesis Introduction
Jan van Helmont - measured plant’s water intake
plants gain most of their mass from water

7. Photosynthesis Introduction
Priestley : took a candle and placed a glass jar over it
watched the flame gradually die out
something in the air was necessary to keep the candle burning: oxygen

8. Photosynthesis Introduction
Priestly’s Second Experiment
placed a live spring of mint under the jar and allowed a few days to pass
the candle would remain lite a while.
Why? mint plant produced oxygen.

9. Photosynthesis Introduction
Jan Ingenhousz - aquatic plants produce oxygen bubbles in the light, but not in the dark
plants need sunlight to produce oxygen.

10. Photosynthesis
plants use energy of sunlight to covert water and carbon dioxide into
high-energy carbohydrates: sugar & starches
oxygen: waste product
Photosynthesis Equation
6CO2 + 6H20 + (light)  C6H12O O2
carbon dioxide + water + (light)  sugars + oxygen

11. Light and Pigments

12. Light Energy Energy travels to the Earth in the form of light.
White light: mixture of different wavelengths/colors

13. Principle Pigment: chlorophyll
Plants gather the sun’s energy with light absorbing molecule called pigments
Principle Pigment: chlorophyll
which is in the chloroplast
chlorophyll a & chlorophyll b
Chlorophyll absorbs light well:
blue-violet, chlorophyll b
red region, chlorophyll a
green light is reflected by leaves

14. Secondary Pigment: Carotene
absorbs light in the red & orange region
leaves turn red, yellow, and orange in the fall

16. Light  Energy When chlorophyll absorbs light, it absorbs energy
Energy is transferred to the electrons in the chlorophyll molecule
Allows photosynthesis to work

17. Reactions of Photosynthesis

18. Chloroplast In the chloroplast, thylakoids are in stacks called grana
Thylakoid organize chlorophyll and other pigments into photosystem.
Photosystems: light collecting units of the chloroplast

19. Photosynthesis Light dependent reaction Thylakoid membrane
Light independent reaction or Calvin Cycle
Stroma: region outside of the thylakoid membrane

20. Electron Carriers electrons gain energy when excited by sunlight
high-energy electrons are transported by electron carriers
electron carriers are called the Electron Transport Chain

21. Electron Carriers
NADP+ - carrier that holds 2 high-energy electrons and H+ ion
NADP+  NADPH
NADPH carries the high-energy electrons throughout the cell
High energy electrons are used to build carbohydrates, like glucose

22. Electron Transport

23. Light-Dependent Reaction
Occurs in the thylakoid membrane
uses energy from light
ADP  ATP
NADP+  NADPH
produces O2 gas

24. Calvin Cycle
Occurs in the stroma: region outside the thylakoid membrane
Uses ATP and NADPH to build high energy sugars
long term energy storage
does not require light

25. Factors Affecting Photosynthesis
Water shortage: slows photosynthesis
Plants in dry conditions have waxy coating to reduce water loss
Temperature: 0-35ºC
Above or below damages enzymes and photosynthesis slows
Light: rate increases with intensity
Maximum exists