Energy – What is it? The ability to do work Energy can not be created or destroyed – Energy is TRANSFORMED Forms of energy – Light, electric, chemical Chemical energy is stored in the electrons of chemical bonds
Biochemical Energy Cells store and release energy using the chemical ATP – Adenosine triphosphate ATP is the “energy currency” of the cell – MANY cellular processes use ATP Cells release energy by breaking a phosphate bond
Photosynthesis Plants convert light energy into chemical energy Energy is stored in the bonds of carbohydrates
Light and Pigments Light travels in waves Colors have different wavelengths “White” light is a mixture of all colors in the visible spectrum Red – longest wavelength, lowest energy
Light and Pigments Plant pigments absorb sunlight Chlorophyll – green pigment needed for photosynthesis – Reflects green light – Absorbs other light
Electron Carriers Light energy “excites” electrons in chlorophyll High energy electrons need special carriers – ie: NADP+ and NAD+
Light Reaction Chlorophyll absorbs light, and electrons become energized Water splits to produce H+ and O2 Electron loses energy to form ATP – ATP goes to Calvin Cycle H+ and NADP forms NADPH – Carries energy to Calvin Cycle
ATP Revisited How do living things use ATP for energy? Where does ATP come from?
Overview of Cellular Respiration 6O2 + C6H12O6 6CO2 + 6H2O + ATP
Overview of Cellular Respiration Energy from glucose is released – In the presence of O2 – Energy is stored in ATP – CO2 is a byproduct 3 Stages – Glycolysis – Krebs Cycle – Electron Transport Chain
Glycolysis In the cytoplasm Glucose breaks into 2 molecules of pyruvic acid (3C) Uses 2 ATP, produces 4 ATP – Net gain of 2 ATP 2 NADH produced Pyruvic acid is used for respiration OR fermentation
Krebs Cycle In the mitochondria Pyruvic acid breaks down Series of 9 rxns which produce: – CO2 – FADH2 and NADH – 2 ATP FADH2 and NADH go on to the ETC to…. – MAKE MORE ATP!!!!
Electron Transport Chain Occurs in mitochondria Uses high energy electrons from FADH2 and NADH to make ATP O2 accepts the final electron forming H2O
Page 229 The Totals Electron carriers which go on the electron transport chain to generate ATP!