Cellular RespirationIn a Nutshell
The PurposeTransfer the energy in macromolecules (like glucose) into a more efficient form for cells (ATP)ATP can then transfer smaller units of energy for cellular work
OverallFood ATP Glucose + O2 + ADP + P CO2 + H2O + ATP
2 TypesAerobicWith oxygenProduces a lot of ATPNeeds mitochondriaAnaerobicWithout oxygenProduces a little ATP
Who Goes Through Respiration?All living organisms go through some sort of cellular respiration (though many do not use the complete process) to make ATPPlants still go through cellular respiration!
Aerobic RespirationGlycolysisKrebs CycleOxidative Phosphorylation
GlycolysisOccurs in all cells ever studied.No oxygen required, no mitochondriaProbably evolved in the earliest forms of life
GlycolysisSugar is split into pyruvate2 ATP are madeSome electrons passed to NAD+ to form NADH
Krebs CycleIf oxygen present, the pyruvate heads into the MitochondriaSeries of enzyme-catalyzed reactions
Krebs CycleRest of sugar broken into Carbon Dioxide (exhale!!!)2 more ATP madeElectrons and H+ picked up by NAD+ to form NADH (and another electron carrier)
So FarSome ATP made (4), but we have a lot of electron carriers (NADH and others) which carry energy in (e-)
Final StageNADH & other carriers drop off H+ and electrons to the final stage called Oxidative Phosphorylation.In OXPHO concentration gradients of H+ are made using the energy of electrons to PUMP H+ from low to high. This process uses an electron transport chain (like in photosynthesis) which allows for the transfer of energy!
e- and H+ dropped offElectron transport chainH+ pumped against C.G.
Transfer energy to ATP BOND The concentration gradient of H+ has potential energy.The only place for energy to move from high to low is in a molecule called ATP synthase. Here the FACILITATED DIFFUSION of H+ turns (kinetic) the molecule of ATP synthase and allows for the formation of the bond (chemical)between the phosphates.
Why do we breathe?At the end of the oxidative phosphorylation process there aree- and H+ hanging out Oxygen picks them up and makes waterIf O2 is absent???TBC
Review Oxidative PhosphorylationLOTS of ATP made (about 34) as electrons are passed from NADH through a series of proteins to O2 to form water
Other macromolecules?Same basic processFuel + Oxygen + ADP + P Carbon Dioxide + Water + ATP
What was that about No Oxygen?No Oxidative phosphorylationNo Krebs CycleOnly source of ATP is glycolysis No O2, No problem!Well for like a minute
BUTGlycolysis needs NAD+, and with no OXPHO the cell runs out of NAD+because NADH cant drop off e- & H+ b/c theres no O2 to pick up at endIf you dont have oxygen you cannot clean up the electrons & H+ & the process comes to a halt. Thus, you cannot produce enough ATPand then your cells will die.Enough cell death & then youll die
So fermentation will occur to remake NAD+ and allow glycolysis to continue TEMPORARILY!
We go through LACTIC ACID FERMENTATIONThis changes pH which is why its temporaryALSO why muscles hurt after working out (b/c your O2 demand is REALLY high during a work out that your cell cant keep up with O2 even if you are breathing like crazy! So you switch to L.A.FOther organisms do ALCOHOLIC FERMENTATION and we use them to make beer, bread, wine
http://vcell.ndsu.nodak.edu/animations/etc/movie-flash.htm electron transport chainhttp://vcell.ndsu.nodak.edu/animations/atpgradient/movie-flash.htm atp synthase process
Just finished the photosynthesis quiz*Use this picture for questions?*Hoover dam! Look it up;)*