cellular respiration:
transformation of chemical energy in the bonds of food into ATP (ie: glucose)
what are the steps of cellular respiration in order:
- glycolysis
- pyruvate oxidation
- krebs cycle (citric acid cycle)
- electron transport chain
what 2 ways can ATP be made:
- substrate phosphorylation
2. chemiosmotic generation
substrate phosphorylation:
-takes place in cytoplasm
-ADP picks up an inorganic phosphate from ATP
The energy required for this endergonic rxn is obtained by coupling w an exergonic rxn (in cytoplasm)
chemiosmotic generation:
- requires a membrane (mitochondria)
- exited electrons cause a shale change in a trans membrane protein
- proteins pump out of these channels
- when protons leak back in, this is coupled w production of ATP from ADP
- protons peak down an electro chemical gradient
when making ATP directly using an enzyme:
a phosphate is transferred from a high energy molecule to ADP (ADP + P = ATP)
What method makes ATP indirectly?
oxidative phosphorylation. using redox, enzymes, protein, electron carriers
electrons contain:
bond energy
role of electron carriers:
pick up 2 electrons + hydrogens to become reduced
(NAD+ -> NADH)
(FAD+ -> FADH2)
role of protein complexes:
NADH + FADH2 (has energy) deliver electrons to protein complexes in mitochondria
- proteins harness energy from moving electrons
protein complexes eventually drive:
ATP synthase. (ADP + P —> ATP)
glycolysis:
- glucoses activation
- anaerobic. no O needed
process of glycolysis:
- energy investment & phosphates added to glucose
- 10 rxns in cytoplasm
- pyruvate created
- exothermic & catabolic process
where does glycolysis take place?
in cytoplasm
where does pyruvate oxidation occur?
matrix in mitochondria
what happens in pyruvate oxidation?
sugar is oxidized (gives up some energy)
- NAD+ —> NADH (takes energy)
- CoA attaches to acetate to produce Acetyl CoA
when fcning anaerobically:
- pyruvate yeasts carry out ethanol
- ethanol and co2 through fermentation
Lactic Acid fermentation:
La production > La use as exercise intensity increases
Lactic acid threshold:
point at where increase begins (occurs at a higher rate after training)
krebs cycle:
- cyclic metabolic pathway
- acetyl CoA is fed into pathway
- carbon atoms from glucose that entered glycolysis will be oxidized by the krebs cycle
where does krebs occur?
in matrix of mitochondria
krebs cycle contains:
02
ETC:
a series of complexes that transfer electrons from electron donors to electron acceptors. (through redox and couples with the transfer of protons across a membrane)
where does etc occur?
mitochondria
