6.1 Mini Lecture Radjewski AP Biology 

ATP Adenosine triphosphate Energy currency in the cell Formed from ADP (adenosine diphosphate) and inorganic phosphate (Pi) with energy Can be broken down by hydrolysis to form ADP and Pi which creates energy! ATP + H20  ADP + Pi + free energy Exergonic, because it is releasing free energy

Two ways ATP can be formed Substrate – level phosphorylation Involves the direct transfer of phosphate to ADP Happens in glycolysis (next section) Oxidative phosphorylation Coupled reaction using a coenzyme called NADH Done through chemiosmosis Diffusion of protons across a membrane driving the synthesis of ATP

What is NADH? Nicatinamide adenine dinucleotide Coenzyme Exists in 2 forms Oxidized form, NAD+ Reduced form, NADH NAD+ + H+ + 2e-  NADH In a cell, the electrons do not remain with NADHa and oxygen accepts them to create Water NADH + H+ + ½ O2  NAD+ + H20 REDOX Oxidation – loss of 1 or more electrons (Oil) Reduction – gain of 1 or more electrons (Rig)

Chemiosmosis Occurs in mitochondria and chloroplasts Remember, middle of cell membrane is nonpolar, therefore protons (H+) cannot easily diffuse through So H+ go through the membranes via H+ channel proteins Due to a bunch of H+’s going through the membrane, a proton gradient forms ATP synthase in the membrane uses the energy of the proton gradient to make ATP

What happens To the H+’s?

Water is formed! Oxidation is always coupled with reduction 2H+ + 2e- + ½ O2  H20 Oxygen is important to accept these electrons in an aerobic organism Water is a product of cellular respiration (next section)

Introduction to Cellular Respiration C6H12O6 + 6 O2  6 CO2 + 6 H20 + chemical energy Carbohydrate usually is glucose C6H12O6 but can be other substances Glucose is oxidized and oxygen is reduced Occurs in all living organisms Occurs in the cytoplasm and the mitochondria Is related to photosynthesis by: Similar reactants/products ATP Reduced coenzymes