Cellular Respiration – A Review of the Process AP BIO

Glycolysis Breaks down glucose into pyruvic acid 2 ATP are added 2 NADH are produced by NAD+ accepting 2 electrons 4 ATP are produced (yielding a net gain of 2 ATP) 2 Pyruvic acid molecules are formed **There are 9 intermediate molecules between glucose and pyruvate**

Krebs Cycle (Citric Acid Cycle) Before the actual cycle begins, pyruvate combines with coenzyme A (CoA) to produce a molecule called acetyl CoA 1 NADH and 1 CO2 is produced The first actual step of the Krebs Cycle is when oxaloacetate combines with acetyl CoA to make citric acid Products: 3 NADH, 1 FADH2, 1 ATP 2CO2 (this is the CO2 that we exhale)

Oxidative Phosphorylation The process of extracting ATP from NADH and FADH2 Electrons from the carriers are passed down an ETC The electrons final acceptor is an Oxygen molecule, and water is formed as a byproduct NADH can produce 3 ATP FADH2 can produce 2 ATP

Chemiosmotic Phosphorylation When the electrons lose energy in O.P. it is used for chemiosmotic phosphorylation As the carriers move through the ETC, H+ are pumped from the matrix, across the cristae, and into the outer compartment creating a proton gradient (Potential Energy Reservoir) Channel proteins (ATP Synthase) in the cristae allow the protons to flow through and use the energy to produce ATP from ADP

2 Types of Phosphorylation Substrate Level – Occurs when a phosphate group and its energy is transferred to ADP to form ATP. The substrate molecule donates the phosphate (occurs in glycolysis) Oxidative Phosphorylation – Occurs when phosphate is transferred but not the energy. Energy is provided from electrons in the ETC

Alcoholic Fermentation Pyruvic Acid is converted into acetaldehyde 1 CO2 and 1 acetaldehyde is produced Acetaldehyde is converted into ethanol 1 ethanol is produced, and 1 NAD+ is produce The entire point of this process is to send NAD+ back to glycolysis to keep slowly producing ATP

Lactic Acid Fermentation Pyruvic Acid is converted to lactic acid NAD+ is given off and sent back to glycolysis