PHOTOSYNTHESIS

INTRO  All living things need energy.  Our energy comes from FOOD!

But, where does a plant get it’s energy from?

The SUN is the source of energy for plants.

Photosynthesis  Photosynthesis is the process that plants use to convert light energy into chemical energy (food).

Photosynthesis Photo means light and synthesis means put together.

 What happens if you just add water and carbon dioxide together?  What happens if you add sunlight to that?

You get: warm carbonated water

Photosynthesis also requires CHLOROPHYLL  Chlorophyll is the main pigment found in plants.  Pigment – a light absorbing molecule  Plants use their pigments to absorb the energy from the sun.

Other “accessory” Pigments  Carotenoids red, orange, yellow red, orange, yellow  Anthocyanins red, purple, blue red, purple, blue  Betalains red, yellow red, yellow

Light from the sun is composed of a range of wavelengths.

Why plants are green  Chlorophyll absorbs red and blue light.  Chlorophyll reflects green light.

Leaf Leaf Cells Chloroplast CHLOROPHYLL IS IN THE CHLOROPLASTS

ATP ATP (adenosine triphosphate).  The molecule that provides energy.  It stores and releases energy. Adenine + Ribose + 3 Phosphate groups

16 It Begins with Sunlight! copyright cmassengale

17 Photoautotrophs Absorb Light Energy copyright cmassengale

18 Inside A Chloroplast copyright cmassengale

19copyright cmassengale

20 Photosynthesis Overview copyright cmassengale

Stage 1 Light-Dependent Reactions  Light energy is used to make ATP and water is split (photolysis) to form oxygen & hydrogen. Occurs in the thylakoids!

22 Light Reaction Summary Reactants: H2OH2OH2OH2O  Light Energy Products:  ATP  NADPH  O 2 and H copyright cmassengale

Stage 2 Calvin Cycle  ATP and H are combined with CO 2 to make sugars. Occurs in the stroma!

24 Calvin Cycle Summary Reactants:  ATP HHHH  CO 2 Products:  Sugar copyright cmassengale

25 Factors Affecting the Rate of Photosynthesis  Amount of available water  Temperature  Amount of available light energy copyright cmassengale

26 Photosynthesis Overview Draw this!

PUTTING IT ALL TOGETHER! Your task now is to draw a picture (or write it out as a summary) of the process of photosynthesis. Please include the following words: carbon dioxideATP waterSunlight sugarsChloroplast oxygenChloropyll Light-DependentCalvin Cycle

CLOSURE  What are the end products of photosynthesis?  What would happen if there were no carbon dioxide left on Earth?

Let’s practice cellular respiration & photosynthesis.  Using your notes and drawings, please complete the following two quizzes:  Chapter 9 assessment on page 237, questions  The test on page 239, questions 1-9.

Answers p. 237p C 2.B 3.B 4.C 5.B 6.B 7.C 8.B 9.A 10.B 1.B 2.E 3.A 4.C 5.C 6.D 7.D 8.C 9.C