Lecture 9 Glycolysis and Fermentation

fermentation

• method of catabolism

• internal organic electron acceptor → regenerate NAD+

• lower energy yield → substrates only partially oxidized

• anaerobic process → can occur in presence of O2

respiration

• method of catabolism

• exogenous (external) electron acceptors such as nitrogen/oxygen

• complete oxidation of e- donors, more energy produced

• aerobic or anaerobic

substrate level phosphorylation

• coupling exergonic reactions directly to ATP synthesis

• enzymatic transfer of phosphorus to ADP

• simplest and evolutionarily oldest way to synthesize ATP

• ex glycolysis

electron transport chains

• way to preserve energy in the cell

  • generates proton motive force

  • oxidative phosphorylation (respiration)

glycolysis

• anaerobic process, O2 can be present

• highly regulated/controlled enzymatic process

• used by fermentative and respiratory organisms

• 2 ATP in, 4 ATP out, NET 2 ATP

fermentation products

• commonly alcohols or acids

• fermentations named after primary products produced from regeneration of NAD+

homofermentative

1 byproduct

heterofermentative

produce several diff molecules as byproducts

• ex lactic acid and ethanol

mixed-acid fermentations

products are multiple acids

• acetic, lactic, succinic, etc

• gut bacteria and E. coli do this

secondary fermentation

organisms obtain energy from fermentation products (wastes) produced by other bacteria

does fermentation make H+ gradient

No

• no PMF

• no ETC

fermentation is aerobic/anaerobic?

anaerobic process

• can be done in presence of oxygen

ATP is made by _____ in fermentation

Substrate level phosphorylation

• high energy bonds made by rearrangement of activated organic compounds