Title: BV2 / BV2 - 2 / Modul 5 / Fermentation

Q: When will pyruvate undergo fermentation?
A: In the absence of oxygen, pyruvate will undergo fermentation

Q: What is fermentation, briefly?
A: In our cells, pyruvate is reduced to lactic acid (lactate) by an enzyme termed lactate dehydrogenase

Q: What is fermentation?
A: Fermentation describes the process of metabolising pyruvate (pyruvic acid) under anaerobic conditions.

Q: Why is fermentation essential?
A: - During glycolysis the coenzyme NAD+ is reduced to NADH. Under anaerobic conditions fermentation guarantees recycling to NAD+ to not stall glycolysis or other hydrogenase activities
- Pyruvic acid is toxic, and its accumulation is associated with severe disease

Q: Which type of fermentation do our cells implement?
A: Lactic acid fermentation

Q: What happens during lactic acid fermentation?
A: The principal process is that pyruvate gains two electrons from NADH, forming lactate, which in turn can travel to the liver, where it is converted back to glucose via gluconeogenesis

Q: What is the overall reaction of lactate fermentation?
A: Pyruvate + NADH → Lactate + NAD +

Q: What happened with NAD+ in step 6 of glycolysis and what does that cause?
A: In step 6 of glycolysis, NAD+ was used to help transform GAP into 1,3-BPG. In this process, the NAD+ was used up and it was not regenerated in the remaining steps. This means that glycolysis, which depends on NAD+, will eventually stop and the cell will not be able to produce ATP

Q: What must happen for glycolysis to proceed after the NAD+ is used up?
A: In order for glycolysis to proceed, the NAD+ must be regenerated.

Q: What does the cell use to regenerate NAD+ molecules?
A: The cell regenerates the NAD+ by metabolising pyruvate molecules

Q: What will pyruvate produce under aerobic conditions?
A: Acetyl-CoA - Krebs and ETC

Q: What will pyruvate produce under anaerobic conditions?
A: - Lactate - humans
- Ethanol - bacteria

Q: What is the process that pyruvate undergoes under anaerobic conditions called?
A: Under
anaerobic conditions, the pyruvate will undergo a process called fermentation

Q: When is lactic acid fermentation used?
A: Many procaryotic and eucaryotic organisms undergo lactic acid fermentation. In fact, when the O2 supply runs low in our cells, they use this process to regenerate NAD+

Q: WHcích enzyme catalyses lactic acid fermentation?
A: This process is catalysed by lactate dehydrogenase

Q: What is the net equation for lactic acid fermentation?
A: Glucose + 2ADP + 2Pi -----> 2 lactate + 2ATP + 2H2O

Q: What does lactate dehydrogenase do in lactic acid fermentation?
A: The lactate dehydrogenase catalyses the transfer of the hydride group

Q: What is lactate?
A: Lactate is the conjugate group of lactic acid

Q: What happens in our muscle cells during exercise?
A: During strenuous exercise, our skeletal muscle cells may not receive an adequate supply of oxygen. Such cells will produce lactate, which will cause fatigue.