MODULE 9: Chapter 9.5 Flashcards
What are the three metabolic fates of pyruvate?
- Metabolized to CO2 and H2O under aerobic conditions
- Converted to lactate under anaerobic conditions
- Converted to CO2 and ethanol in some microorganisms
What is the net yield of ATP from the complete oxidation of 1 mole of glucose by aerobic metabolism?
32 moles of ATP
What enzyme converts pyruvate to lactate during anaerobic conditions?
Lactate dehydrogenase
Which microorganism is used in the dairy industry to produce yogurt and cheese by converting pyruvate to lactate?
Lactococcus lactis
What are the enzymes used by yeast to convert pyruvate to CO2 and ethanol?
Pyruvate decarboxylase and alcohol dehydrogenase
What critical function does pyruvate metabolism serve in all three pathways?
To regenerate the oxidized form of the coenzyme NAD⁺
True or False: NAD⁺ is regenerated in the cytoplasm during lactate and ethanol production.
True
What happens to NAD⁺ regeneration when pyruvate is fully oxidized in the mitochondria?
It requires a complex mitochondrial shuttle system
What genetic disease is caused by defects in the enzyme lactate dehydrogenase?
Lactate dehydrogenase deficiency
What is the consequence of lactate dehydrogenase deficiency during intense exercise?
Inability to produce sufficient ATP for muscle contraction
What does the lactate dehydrogenase reaction couple?
The reduction of pyruvate to lactate with the oxidation of NADH to produce NAD⁺
What is the primary carbohydrate source used in beer production?
Cereal grains such as barley
What is the purpose of mashing in beer production?
To release metabolic enzymes from crushed germinated barley
Fill in the blank: The metabolic enzymes activated during mashing degrade carbohydrates and proteins to generate _______.
metabolites for the glycolytic pathway
What occurs after the wort is boiled in the beer production process?
A live yeast culture is added under aerobic conditions
What is the process called when yeast ferments sugars under anaerobic conditions to produce ethanol and CO2?
Alcoholic fermentation
What happens during the second fermentation step used by microbreweries?
A small amount of sugar and fresh yeast is introduced to carbonate the filtered beer
How common is lactate dehydrogenase deficiency in the population?
It is a recessive genetic disease and heterozygous carriers are common
What situation may reveal a defect in lactate dehydrogenase for carriers of mutations?
Attempting intense anaerobic exercise
