(U3) 6A: Aerobic Cellular Respiration

cellular respiration

the process by which cells create usable energy in the form of ATP from a series of biochemical reactions, involving the breakdown of glucose

glucose

a simple 6-carbon sugar molecule with the formula C6H12O6

ATP

adenosine triphosphate, a high energy molecule that, when broken down, provides energy for cellular processes

aerobic cellular respiration

cellular respiration that occurs in the presence of oxygen. Involves three stages, during which glucose and O2 are converted into ATP, CO2, and water

anaerobic fermentation

a metabolic pathway that occurs in the absence of oxygen. Involves glycolysis, followed by further reactions that convert pyruvate into lactic acid in animals, or ethanol and CO2 in yeast

glycolysis

the first stage of aerobic cellular respiration in which glucose is converted to two pyruvate molecules

Krebs cycle

the second stage of aerobic cellular respiration, where multiple reactions occur to create ATP, NADH, FADH2, and the waste product CO2. Also known as the citric acid cycle or TCA cycle

electron transport chain

the third stage of aerobic cellular respiration, in which a series of protein complexes embedded in the inner membrane of a mitochondrion harness the stored energy in NADH and FADH2 to generate large amounts of ATP

mitochondrion (pl. mitochondria)

a double-membrane-bound organelle that is the site of the second and third stages of aerobic cellular respiration

cytosol

the aqueous fluid that surrounds a cell's organelles inside the plasma membrane

mitochondrial matrix

the space inside the inner membrane of a mitochondrion. The site of the Krebs cycle

crista (pl. cristae)

the folds of the inner membrane of a mitochondrion. The site of the electron transport chain

pyruvate

a three-carbon molecule that can be formed from the breakdown of glucose via glycolysis

nicotinamide adenine dinucleotide (NAD)

a coenzyme that acts as a proton (H+) and electron carrier in cellular respiration. NAD can cycle between its NAD+ and NADH forms, depending on the reaction it takes part in

flavin adenine dinucleotide (FAD)

a coenzyme that acts as a proton (H+) and electron carrier in cellular respiration. FAD can cycle between its FAD and FADH2 forms, depending on the reaction it takes part in

coenzyme A

a large organic nonprotein molecule that plays a key role in the modification of pyruvate to allow it to enter the Krebs cycle. Also known as CoA

acetyl-CoA

the product of the link reaction where pyruvate is conjugated to coenzyme A, creating the primary input into the Krebs cycle

ATP synthase

an enzyme in the inner mitochondrial membrane that uses the concentration gradient of H+ to synthesise ATP from ADP and Pi

catalyse

to increase the rate of a reaction