Photosynthesis What do you know about photosynthesis? –What is it?? –Who does it? –Where does it happen? –How does it happen?

Photosynthesis: What is it? Photosynthesis is part of the carbon cycle.

Photosynthesis: What is it? Converting the solar energy from the sun into chemical energy stored in glucose. –Glucose is a molecule that is part of many carbohydrates (i.e. starch) The glucose can later be used to fuel life processes

Photosynthesis: who does it? Autotrophs –Organisms that make their own food Some bacteria Plants Some fungus (lichen) Some plankton

Photosynthesis: where does it happen? In plant cells, photosynthesis takes place in the CHLOROPLAST –Thylakoid Where light is captured Where ATP is made –Stroma Where glucose is made

Photosynthesis: how does it happen? 1.Light absorption by pigments in the thylakoid Requires sun light 2.Light energy converted to ATP in the thylakoid Requires water (from the roots) Releases oxygen (through the stomata) 3.ATP used to convert CO 2 to glucose in the stroma Requires CO 2 (enters plants through the stomata)

Light from the sun is composed of waves of a variety of wavelengths Different wavelengths leads to different colors –Visible spectrum Step 1: Light absorption by pigments

Pigments: chemicals that absorb light of various wavelengths. In many plants, chlorophyll is the pigment that absorbs light energy Chlorophyll is found in the thylakoid of the chloroplast Chlorophyll absorbs all but green wavelength light –Green light is reflected, so we see green plants

Step 2: Light energy converted to ATP Once solar energy is absorbed, the energy is used to make ATP. –ATP = adenosine triphosphate ATP is a molecule that contains lots of energy in its chemical bonds This step requires water (absorbed via the roots) This step takes place in the thylakoid

Step 3: ATP used to convert CO 2 to glucose The energy in ATP bonds is used to make glucose using CO2 This step happens in the stroma The CO2 enters the leaf from the stomata

Photosynthesis Overall 1.Light absorption by pigments Requires sun light 2.Light energy converted to ATP Requires water, releases oxygen 3.ATP used to convert CO 2 to glucose Requires CO 2 H 2 O + CO 2 Glucose + O 2 SOLAR ENERGY

Recipe for Photosynthesis Take a little Carbon Dioxide present in the air, Add a bit of water that's found everywhere. If the plant has chlorophyll then add a dash of light, And you'll know the recipe for photosynthesis will turn out all right. Green plants get their energy from the sun, And form the base of food chains for everyone. Plants make glucose the fuel that we need, When we eat this sugar, energy is freed. As if this isn't enough for the green plants to do, They release oxygen to the atmosphere too. Plants bring beauty to the world that we see, We get many products from the trees. Even if you're a carnivore and eat a plant you can't. Just remember that meat's energy begin with a plant.