BIO1011 Lecture Notes - Lecture 13: Cellular Respiration, Glyceraldehyde, Cytosol
Cellular Respiration
Aerobic Respiration
•Cellular respiration is best explained by following the journey of a single glucose
molecule
•It is the process that creates ATP in the largest amounts for cell use
•It involves many stages but there are 3 main steps
•The general process involves removing H to provide energy
C6H12O6 + 6O2 → 6CO2 + 6H2O + 36(38) ATP
Glycolysis
•When you eat food, it is broken down into glucose
•The glucose moves to the cytosol of the cell
•The first 5 reactions that happen to glucose in the cytosol are priming reactions that
serve the purpose of raising the energy level of the molecule
•In two of these reactions, ATP is being spent:
•during the conversion of glucose to glucose-6-P
•during the conversion of fructose-6-P to fructose-1, 6-P2
•
•It is not important to remember the names of these intermediate steps, but to
understand that energy needs to be added to glucose in order to get it to a state
where energy can be extracted from the molecule.
•By the end of the priming sequence, one glucose has been converted to
glyceraldehyde-3-P
•Although both dehydroxacetone phosphate and glyceraldehyde-3-P are produced
and oscillate, the glyceraldehyde is being removed and converted into 1,3
biphosphoglycerate. This means the equilibrium will favour the production of
glyceraldehyde-3-P.
Diagram of Priming Reactions
Document Summary
C6h12o6 + 6o2 6co2 + 6h2o + 36(38) atp. Krebs cycle/ citric acid cycle: if o2 is present, the process moves to the matrix of the mitochondria, the pyruvate enters via a transport protein. You immediately get an oxidative decarboxylation, where the pyruvate is oxidised and a carbon in removed, creating. The resulting compound releases co2 and becomes a-ketoglutarate (d) a-ketoglutarate is oxidised, reducing nad+ to nadh, and releasing. The remaining four-carbon molecule picks up coenzyme a, forming succinyl coa. (e) the coa of succinyl coa is replaced by a phosphate group which is then transferred to adp to make atp. The four carbon molecule that is created in called succinate. (sometimes guanine triphosphate/gtp) (f) succinate is oxidised, forming fumarate. Two hydrogen atoms are transferred to fad, producing fadh2. (g) water is aded to fumarate, converting it to malate. (h) malate is oxidised, producing oxaloacetate, the starting compound.
