RespirationThe process in which organisms breakdown glucose.

The energy in the chemical bonds of glucose is eventually captured in ATP molecules for use by

an organism to do work

C6H12O6 + 6 O2 6CO2 + 6 H2O + ATP energy

Occurs in 3 major steps

glycolysis

Krebs cycle

Electron transport system (ETS)

Redox RxKey to transferring energy from one

molecule to another

Glucose ATP

As e- ‘fall’ from molecule to molecule (oxidation/reduction), energy is captured to form

ATP from ADP and phosphate group

Organisms use ATP as energy source to do work

glycolysis

Occurs in cytoplasm

10 step process

Prokaryotes and eukaryotes

anaerobic

Net 2 ATP (by substrate level phosphorylation)

2 NADH (nicotinamide adenine dinucleotide)

2 pyruvate (3C)

Glycolysis stepsglucose

(hexokinase) and ATP ADP

Glucose 6-phosphate

(phosphoglucoisomerase)

Fructose 6-phosphate

*(phosphofructokinase) and ATP ADP

Fructose 1,6-biphosphate

(aldolase) *Allosteric enzyme inhibited By ATP and citrate

Glycolysis stepsX 2 Glyceraldehyde phosphate

(triose phosphate dehydrigenase)+ 2 NADH + 2 H+

1,3-diphosphoglycerate (phosphoglycerokinase)

+ ATP

3-phosphoglycerate (phosphoglyceromutase)

2-phosphoglycerate

(endolase) + 2 H2O

Glycolysis stepsX 2 phosphoenolpyruvate

( pyruvate kinase)+ ATP

pyruvate

Final products of glycolysis = 2 pyruvate2 NADH2 ATP (net)

Pyruvate Krebs cycle if aerobicfermentation if anaerobic

NADH + H+ ETS

ATP do ‘work’

fermentationIn anaerobic conditions, pyruvate molecules are broken down in a process called fermentation

Alcohol fermentation (yeast, fungi, bacteria)

Products = ethanolCO2

NAD+ (recycled)

Krebs cycleIn aerobic conditions, pyruvate enters the Krebs cycle(runs X2 for each glucose)

In mitochondria

Eukaryotes only

Hans Krebs

Products = 2 ATP (by substrate level phosphorylation)NADHFADH2

Krebs cycle Pyruvate converted to acetyl CoA

Requires coenzyme AGives off CO2 and NADH

Acetyl CoA combines with oxaloacetic acid

Forms citric acid

Citric acid isocitrate -ketoglutaric acid Succinyl CoA succinate fumarate Malate Oxaloacetic acid (to start cycle over)

Krebs cycle stepsKrebs cycle products

Oxaloacetic acid regenerated to run cycle

2 ATP to do ‘work’

6 NADH + 6 H+ ETS

2 FADH2 ETS

6 CO2

ETSEnergy in e- from NADH and FADH2 travel‘down’ series of electron carriers in redox RxEnergy used to pump H+ from matrix to intermitochondrial space

H+ diffuse through ATP synthase to make ATP (chemiosmosis)Back into matrix

H+ + e- combine with O2 to form water

O2 final e- acceptor

Electron Transport Chain: The Movie

ETSO2 used to combine with 2H+ and 2e- to form H2O

NAD+ regenerated for Krebs cycle

FAD+ regenerated for Krebs cycle

32-34 ATP generated via chemiosmosis

Total ATP = 2 + 2 + 34 = 38

Cellular Respiration

versatilityFat catabolism

Glycerol glyceraldehyde phosphate

Fatty acids acetyl CoA via beta oxidation

Amino acids Krebs cycle after deaminated

Protein catabolism

Anabolic pathways

AA from Krebs

Glucose from pyruvate

Fatty acids from acetyl CoA