Transcript Document
Photosynthesis • SC.912.L.18.7 Trapping Energy from Sunlight • The process that uses the sun’s energy to make simple sugars is called photosynthesis. Trapping Energy from Sunlight • Photosynthesis happens in two phases. 1. The light-dependent reactions convert light energy into chemical energy. • Sunlight strikes chlorophyll molecules and gives additional energy to electrons. • The energetic electrons are passed to the electrontransport chain. • This forms ATP, NADPH and releases Oxygen Trapping Energy from Sunlight 2. The molecules of ATP produced in the lightdependent reactions are then used to fuel the light-independent reactions that produce simple sugars. This is also called the Calvin Cycle. • CO2 is added to a five-carbon sugar ( RuBP) to form the first intermediate. • The general equation for photosynthesis is written as 6CO2 + 6H2O→C6H12O6 + 6O2 Trapping Energy from Sunlight Click here to view movie. It will open in a separate window. Restoring electrons • The oxygen produced by photolysis is released into the air and supplies the oxygen we breathe. • The electrons are returned to chlorophyll. • The hydrogen ions are pumped into the thylakoid, where they accumulate in high concentration. Day 2 – Visible Light Quick lab • Use a prism to show that visible light can be broken into multiple colors. • Look at the different pigments found in a leaf. Why do you think the leaf makes more than just green pigment? Question 1 The process that uses the sun’s energy to make simple sugars is ________. A. cellular respiration B. glycolysis C. photosynthesis D. photolysis The answer is C. Photosynthesis happens in two phases to make simple sugars and convert the sugars into complex carbohydrates for energy storage. Question 2 The function accomplished by the lightdependent reactions is ________. A. energy storage B. sugar production C. carbon fixation D. conversion of sugar to PGAL The answer is A. The light-dependent reactions transfer energy from the sun to chlorophyll, and pass energized electrons to proteins embedded in the thylakoid membrane for storage in ATP and NADPH molecules. Sun Light energy transfers to chlorophyll. Chlorophyll passes energy down through the electron transport chain. Energized electrons provide energy that splits H2 O H+ NADP+ bonds P to ADP forming oxygen ATP released NADPH for the use in light-independent reactions Question 3 In which of the following structures do the light-dependent reactions of photosynthesis take place? A. C. B. D. The answer is D. The light-dependent reactions of photosynthesis take place in the thylakoid membranes of chloroplasts. Question 4 • Explain why the roots words photo and synthesis make sense for this reaction. Question 5 • Why do you think the preferred equation for photosynthesis is • 6CO2+6H20 C6H12O6 + 6O2 • And not • CO2+H2O C6H12O6 + O2