hill.com/sites/0072507470/student_view0/cha pter25/animation__how_the_krebs_cycle_wor...

Post on 20-Jan-2016

235 views 0 download

Transcript of hill.com/sites/0072507470/student_view0/cha pter25/animation__how_the_krebs_cycle_wor...

C6H12O6 (s) + 6 O2 (g) → 6 CO2 (g) + 6 H2O (l) ΔG = -2880 kJ per mole of C6H12O6

Step coenzyme yield ATP yield Source of ATP

Glycolysis preparatory phase -2

Phosphorylation of glucose and fructose 6-phosphate uses two ATP from the cytoplasm.

Glycolysis pay-off phase

4 Substrate-level phosphorylation

2 NADH 4–6

Oxidative phosphorylation – Each NADH produces net 2 ATP due to NADH transport over the mitochondrial membrane

Oxidative decarboxylation of pyruvate

2 NADH 6 Oxidative phosphorylation

Krebs cycle

2 Substrate-level phosphorylation

6 NADH 18 Oxidative phosphorylation

2 FADH2 4 Oxidative phosphorylation

Total yield 36–38 ATP

From the complete oxidation of one glucose molecule to carbon dioxide and oxidation of all the reduced coenzymes.

Why are Krebs and ETC considered aerobic?

What would happen if O2 levels are low?

Anaerobic respiration = fermentation

Some Lactobacillus species are used for the production of yogurt, cheese, sauerkraut, pickles, beer, wine, cider, kimchi, chocolate, and other fermented foods, as well as animal feeds, such as silage. Sourdough bread is made using a "starter culture," which is a symbiotic culture of yeast and lactic acid bacteria growing in a water and flour medium. Lactobacilli, especially L. casei and L. brevis, are some of the most common beer spoilage organisms. The species operate by lowering the pH of the fermenting substance by creating the lactic acid, neutralising it to the desired extent.

By fermentation the yeast species Saccharomyces cerevisiae converts carbohydrates to carbon dioxide and alcohols - for thousands of years the carbon dioxide has been used in baking and the alcohol in alcoholic beverages.[5] It is also extremely important as a model organism in modern cell biology research, and is one of the most thoroughly researched eukaryotic microorganisms. Researchers have used it to gather information about the biology of the eukaryotic cell and ultimately human biology.[

Staph aureus Listeria monocytogenes Obligate anaerobes

Clostridium diffcile Clostridium tetani

Facultative anaerobes