Oxidation and Reduction

My AP Biology Thoughts Unit 3 Cellular Energetics

Welcome to My AP Biology Thoughts podcast, my name is Victoria Villagran and I am your host for episode # 70 called Unit 3 Cellular Energetics: Oxidation and Reduction. Today we will be discussing Oxidation and Reduction

Segment 1: Introduction to Oxidation and Reduction

• They are redox reactions, a type of chemical reaction that involves a transfer of electrons between two species, and are vital to the basic functions of life, including photosynthesis
• Specifically, an oxidation-reduction reaction is any chemical reaction in which the oxidation number of a molecule, atom, or ion changes by gaining or losing an electron. Energy can also be transferred by the transfer of electrons in reduction-oxidation
• Reduction is the gain of one or more electrons; endergonic reactions
• Oxidation is the loss of one or more electrons; exergonic reactions
• They always happen together
• The more reduced a molecules is, the more energy is stored in its bonds
• OIL RIG (Oxidation Is Loss; Reduction Is Gain)

Segment 2: More About Oxidation and Reduction in Cellular Respiration

• Cellular Respiration: glucose is oxidized and oxygen is reduced and
• Only looking at where molecules are being either reduced or oxidized
• Glycolysis
• Glucose is being slowly oxidized as it is being converted into pyruvate, and then that electron is added to NAD+, reducing NAD+, converting it to NADH.
• This produce 4 ATP, 2 Pyruvates, and 2 NADH from 2 ATP, 2 NADH+, and Glucose
• The energy in oxidizing glucose or lost from it was lost as heat
• Pyruvate Oxidation
• Pyruvate is oxidized (removing electrons) which then that electron reduced NAD+ to NADH, connecting glycolysis to the citric acid cycle
• This produces NADH, Acetyl CoA, CO2 from Pyruvate and Coenzyme A, and energy is released from the oxidation reaction and lost as heat
• Citric Acid Cycle
• Acetyl CoA (2C) reacts with oxaloacetic acid (4C) to form citric acid (6C); citrate gets oxidized and loses carbons in the form of CO2. In that process, NAD+ and FAD are reduced into NADH and FADH2. Oxaloacetate is regenerated.
• The acetyl group is what is left of the glucose and is broken down (metabolized) in the citric acid cycle