Lecture 7 – RespirationCellular respiration is how we derive energy from the food we eat.

ATP is the currency of our energy. Everything we do is via ATP.

The phosphate groups are terrible for each other the ATP molecule can shoot one of the phosphate groups off making ADP, this releases energy and since there are water molecules floating around an OH- group will replace the phosphate group making the molecule more stable. One molecule of Glucose = 38 ATP.

ATP

3 Stages of Cellular Respiration Glycolysis

o “Breaking down of the Glucose” Occurs within the cytoplasm of the cell.o Glucose 2 Pyruvate Moleculeso Glycolysis needs the investment of 2 ATP to work and ends up generating the 4

ATP, 2 Pyruvate Molecules, and 2 NADH (Used to power more ATP Production).o Capable of taking place without Oxygen however in the absence of Oxygen the

alternate path of fermentation will take place. Fermentation which can result in alcohol for some organisms however humans create lactic acids will feel sore.

The Krebs Cycleo Aerobic Process, occurs at the inner membrane of the mitochondria.o Takes the products of glycolysis, 2 Pyruvate and works them to create another 2

ATP per glucose molecule, and more energy.1. One of the pyruvates is oxidized (Combined with Oxygen) and leaves the

cell as CO2. The remainder is a two-carbon compound called acetyl coA.

2. Then an NAD+ comes along and takes a hydrogen to become NADH. The two pyruvates create two molecules of NADH to be used later.

3. Bring a phosphate with an ADP to create an ATP molecule for each pyruvate.4. Enzymes help join acetyl coA and a 4-carbon molecule to create citric acid.

NAD+ and FAD are like big batteries that take hydrogen and energized electrons from pyruvates which charges them up which results in NADHs and FADH2. One pyruvate yields 3 NADHs and 1 FADH2 per cycle.

Electron Transport Chaino Aerobic Processo When glucose is oxidized during glycolysis and the Krebs cycle, the co-enzymes

NAD+ and FAD are reduced to NADH + H+ and FADH2.

Exergonic, the release of free energy is usually spontaneous (Don’t require energy).

Catabolism The breakdown of complex molecules to form simpler ones with the release of energy. -ΔG and is usually spontaneous. While the pathway is overall negative -ΔG some steps can have a positive change in free

energy. -ΔG is the overall sum of the reactions but each individual reaction doesn’t have to be.

Anabolism The synthesis of complex molecules from simple ones with the storage of energy. +ΔG and once again some reactions in the pathway can be spontaneous but overall

there is a positive free change in energy.

Energy coupling reactions is the way to make reactions with a positive change in energy proceed. The endergonic reaction is coupled with the exergonic reaction. The sums of two reactions and if the overall change is negative then the reaction will proceed.

ATP is the energy currency of the cell. It was advantageous to an organism to settle on using one currency.