Cell respiration

Cell respiration

Is a redox reaction that is catabolic and exergonic

glucose is broken down

the energy released by the breakdown of glucose is coupled to oxidative phosphorylation, power the synthases of ATP

“coupling”

Doesnt happen without energy

What does respiration begin with?

Begins with glycolysis in the cytoplasm

Anaerobic respiration

requires fermentation

happens in the cytoplasm

Aerobic respiration

in eukaryotes happens in the mitochondria

includes the citric acid cycle and oxidative phosphorylation

makes about 30-36 ATP

Glycolysis

Almost universal process

happens in prokaryotes and eukaryotes

occurs outside of the mitochondria in the cytoplasm

Glucose is split into 2 molecules of pyruvate

requires 2 ATP but produces 4 ATP so total net ATP is 2

2 NAD+ are reduced to NADH (electron carriers)

if oxygen is present the pyruvate is transported into the mitochondria

Fermentation

No O2 is present

super wasteful

most of the energy stored in the bonds of glucose is not harvested

NADH is oxidized back into NAD+

pyruvate is reduces into another compound

process is reversible so that ince O2 is available, end product can be fully broken down.

The link reaction

O2 is present

happens after glycolysis

in eukaryotic cells pyruvate is transported into the mitochondria matrix

in prokaryotic cells, folds in the cell membrane are used

CO2 is removed from each pyruvate to make acetyl coenzyme

NAD+ are reduced to form NADH + H+

Citric Acid cycle

as each bond from the original glucose molecule is broken the energy is collected by electron carrier molecules

2 more CO2 released

3 NAD+ reduced to NADH + H+

1 FAD reduced to FADH2

1 ATP produced

cycle happens 2x for each glucose

Oxidative Phosphorylation

Located in the inner mitochondrial membrane

NADH and FADH2 are oxidized

As the electrons move through the proteins in the ETC their energy is harnessed to pump the H+ ions into the intermembrane space

Oxygen is in the terminal electron acceptor, once the electrons have passed all the way through the ETC, oxygen captures 2 electrons and 2 H+ ions to make into H2O.

FAD and NAD+ return back to glycolysis or the citric acid cycle

Chemiosmosis

the etc causes a proton gradient

protons diffuse back into the matrix through ATP synthase

The free energy is released as the H+ ions move through is used to form ATP and ADP and Pi

uncupling to release heat

in cellular respiration uncoupling oxidative phosphoylation from electron transport generates heat. this heat can be used by endothermic organisms to regulate body temp.