A study of photosynthesis & cellular respiration! UNIT 4: ENERGETICS!! A study of photosynthesis & cellular respiration!

Energy in Cells All cells need energy to do work! Producers turn light energy into chemical energy (stored in the bonds of glucose)= Photosynthesis Consumers, in turn, break those bonds in glucose to release usable energy = Respiration High energy molecules = ATP (adenosine tri-phosphate) When the bonds b/t 2 phosphates are broken, a phosphate group and NRG are released!

ATP Video

Photosynthesis sunlight + water + carbon dioxide  glucose + oxygen An organism that carries on photosynthesis is called an AUTOTROPH

Where does it take place? Inside the chloroplast Contains a green pigment known as chlorophyll….. Grana (stacks of “dishes”/thylakoids) & stroma (dense fluid)

Factors that affect the rate of photosynthesis Today, we are going to complete a simulation to see how the following variables affect the rate of photosynthesis: A. Light Intensity B. Level of CO2 C. Color of Light (Wavelength) D. Temperature water weed

Stage 1: Light-Dependent Reactions Requires sunlight Take place in the thylakoid membranes of the grana Sunlight strikes leaf, electrons in chlorophyll get excited to higher energy level….as they fall back down through an electron transport chain, they lose energy (much like a hot potato), which is used to turn ADP into ATP

Stage 1: Light-Dependent (continued) Water (H2O) is split through a process called photolysis…. 1. O2 is released 2. H+ are picked up by NADP (hydrogen acceptor molecule) which goes on to the next reactions as NADPH 3. Electrons are used to replace those lost in the chlorophyll

Stage 2: Light – Independent Reactions Take place in the stroma of the chloroplast Also called the Calvin Cycle (after Melvin Calvin)…one of the end products initiates the start, hence it is a cycle Use the ATP and NADPH from the light reactions to turn CO2 into glucose (C6H12O6) through a series of steps! Each glucose contains 6 C atoms, therefore it takes 6 rounds of the Calvin Cycle to make 1 molecule of glucose!!!!

What wavelength of light do plants photosynthesize the best under? Light travels in wavelengths…ROY G. BIV (remember him?) Hint: Think about these questions… Why is the sky blue? What wavelength is being reflected? Let’s check to see if you are correct…http://www.ncwiseowl.org/

Illuminating Photosynthesis NOVA Online | Methuselah Tree | Illuminating Photosynthesis