Cellular RespirationIn a Nutshell

The Purpose

Transfer 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

Overall

Food ATP

Glucose + O2 + ADP + P CO2 + H2O + ATP

2 Types

AerobicWith oxygenProduces a lot

of ATPNeeds

mitochondria

AnaerobicWithout

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 ATP

Plants still go through cellular respiration!

Aerobic Respiration

GlycolysisKrebs CycleOxidative

Phosphorylation

Glycolysis

Occurs 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 Cycle

If oxygen present, the pyruvate heads into the Mitochondria

Series of enzyme-catalyzed reactions

Krebs Cycle

Rest 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 Far…

Some ATP made (4), but we have a lot of electron carriers (NADH and others) which carry energy in (e-)

Final Stage

NADH & 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 off

Electron transport chain

H+ 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 are

e- and H+ hanging out

Oxygen picks them up and makes water

If O2 is absent???TBC…

Review Oxidative Phosphorylation

LOTS 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 process

Fuel + Oxygen + ADP + P Carbon Dioxide + Water + ATP

What was that about No Oxygen?

No Oxidative phosphorylation

No Krebs Cycle

Only source of ATP is glycolysis

No O2, No problem!

Well for like a minute

BUT… Glycolysis needs NAD+, and with no OXPHO the cell

runs out of NAD+

because NADH cant drop off e- & H+ b/c there’s no O2 to pick up at end…

If you don’t have oxygen you cannot “clean up” the electrons & H+ & the process comes to a halt. Thus, you cannot produce enough ATP…and then your cells will die.

Enough cell death & then you’ll die

So fermentation will occur to remake NAD+ and allow glycolysis to continue TEMPORARILY!

Review

Aerobic

Review

Anerobic

We go through LACTIC ACID FERMENTATION

This changes pH which is why it’s temporary

ALSO why muscles hurt after working out (b/c your O2 demand is REALLY high during a work out that your cell can’t keep up with O2 even if you are breathing like crazy! So you switch to L.A.F

Other 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 chain

http://vcell.ndsu.nodak.edu/animations/atpgradient/movie-flash.htm atp synthase process