Aerobic Cellular Respiration

How many steps are in aerobic respiration?

Three steps: Glycolysis, Krebs cycle, Electron transport chain

Glycolysis

Glucose is broken up into 2 molecule of pyruvate. All organisms perform this step

Krebs cycle

Happens in the mitochondrial matrix. Pyruvate is oxidized in order to reduce electron carriers into NADH and FADH₂. 2 molecules of ATP are produced for every glucose molecule that enters glycolysis

Electron transport chain

Takes place on the fold of the folds of the mitochondrial membrane (cristae).Electron carriers are oxidized in order to create a bunch of ATP. The electrons from oxidation are used to reduce oxygen and form water. (oxidative phosphorylation)

How much ATP is produced during cellular respiration?

A maximum of 38 ATP

Energy Investment Phase (glycolysis)

2 ATP is used to phosphorylate glucose. Glucose then becomes unstable and splits into 2 G3P. Phosphofructokinase carries out the next phosphorylation step.

How is phosphofructokinase an example of feedback inhibition?

When too much ATP is produced during glycolysis, it’s then used to fill the allosteric site of the enzyme to prevent more glycolysis

Energy Payoff/Energy Harvesting Phase (glycolysis)

The 2 G3P molecules are oxidized. The energy and electrons are used to form 2 NADH and 4 ATP. ATP is formed through substrate level phosphorylation

Substrate level phosphorylation

Phosphate is taken from molecules to turn ADP into ATP

What is left at the end of glycolysis?

2 pyruvate formed after the oxidation of G3P, 2 NADH, and 2 net ATP (4 were formed, but 2 used

Pyruvate Conversion

The pyruvate from glycolysis is oxidized and becomes an acetyl group. The acetyl group binds to coenzyme A to form Acetyl CoA

What are the main steps of the krebs cycle

1.) Acetyl CoA is oxidized and the electrons are used to reduce NAD+ and FAD into NADH and FADH₂

2.) The carbon atoms from what was originally glucose are released

3.) Substrate level phosphorylation forms 2 ATP/molecule of glucose

How does the electron transport chain work?

Electron carriers are oxidized and the electrons move down the ETC through proton pumps. The movement of electrons powers the formation of an H+ gradient. This moves H+ ions into the matrix of the mitochondria, where they then move out through ATP Synthase

How does ATP Synthase work?

H+ ions move through the enzyme, which powers it so it can create ATP

What is oxygen’s role in the ETC?

Something has to accept the remaining parts of the ETC. Oxygen is reduced by the electrons that moved through the ETC, and it binds with the H+ ions to form water