5.1 Cellular Respiration Flashcards
Steps of Cellular Respiration
Glycolysis - In cytoplasm
Link Reaction - Matrix
Krebs Cycle - Matrix
Oxidative phosphorylation - Inner membrane
Glycolysis
1) Addition of 2 phosphate to make a more reactive molecule using
2x ATP
2) Lysis of hexose bisphosphate as it is unstable (2x GP)
3) Addition of another phosphate group to make triose bisphosphate
4) Oxidation of triose bisphosphate to remove H atoms
Makes pyruvate
Products of Glycolysis
2x Pyruvate
2x NADH molecules
2x ATP
Link Reaction
1) Pyruvate is decarboxylated and dehydrogenated
This produces acetate
2) Coenzyme A now combines with the acetate to form Acetyl Coenzyme A
Krebs Cycle
1) Acetyl Coenzyme A combines with oxaloacetate to form citrate
2) Coenzyme A goes back to LR to be reused
3) Citrate is decarboxylated + dehydrogenated
The H reduces NAD
5C compound is formed
4) 5C molecule loses CO2 + H to form oxaloacetate again
Cycle happens twice
Products of Krebs Cycle
6x NADH
2x FADH2
2x ATP
Oxidative Phosphorylation (ETC)
1) NADH and FADH2 are carrying H atoms from glycolysis + Krebs
2) They donate the first e- to the first e- transport molecule of ETC
3) e- pass along the chain in a series of redox reactions, releasing energy
4) At the end of the chain the e- combine with H+ and O2 to make H2O
5) O2 is the final electron acceptor in the ETC
Oxidative Phosphorylation (Chemiosmosis)
1) Energy released by the e- is used to actively transport H+ acroos the inner membrane into the intermembrane space
2) This allows a CG of H+
3) H+ then use facilitated diffusion to diffuse back into the matrix
4) This happens through ATP synthase channels in the inner membrane
5) The movement of H+ provides energy for ATP synthesis
ATP production
32 ATP per glucose molecule
Anaerobic Respiration
No Oxygen
No ETC
No Krebs
Only 2 ATP per glucose
Lactate Problems
Causes a build up of H+ ions
Lowers pH
Lowers enzyme function
Leads to muscle fatigue
Lactate Formation
1) NADH from glycolysis can accumulate and must be removed
2) To get rid of it pyruvate takes up 2 H atoms from NADH
3) This forms lactate
Ethanol Formation in Plants
1) Pyruvate takes up 2 H atoms from NADH
2) Pyruvate is decarboxylated to form ethanal
3) Ethanal is alcohol dehydrogenase to form ethanol
Lipids
1) hydrolysed into glycerol + fatty acids
2) Glycerol is phosphorylated
3) Converted into TP
4) TP converted into pyruvate
5) Fatty acids are hydrolysed into acetate
Proteins
1) Hydrolysed into amino acids
2) Deamination occurs
3) Molecule converted into either pyruvate or acetyl CoA
