The correct answer is "knee j*rk reaction". The knee j*rk reaction is a type of reflex wherein nerve impulses from the muscle does not have to reach the brain for the appropriate motor response of the body. Reflexes are important as to shorten the response time especially in times when a long response time will harm the body.
Absence of oxygen means anaerobic respiration ; which has 2 different pathways.
First Pathway ; Alcoholic fermentation which takes place in yeast.
Pyruvate is decarboxylated into ethanal releasing co2 as waste product.
Ethanal is toxic , so its reduced by help of NADH to ethanol in presence of alcohol dehydrogenase enzyme , and Free NAD is released to continue glycolysis.
2) The second pathway is Lactic fermentation which takes place in mammalian muscles.
Pyruvate accepts hydrogen and is converted to lactate by the help of enzyme lactate dehydrogenase , again free NAD is released to continue glycolysis.
Hope I made it clear enough :)
Organism, organ system, Organ, Tissue, Cell
Biosphere, organisation, ecosystem, community, population
Population, organism, organ system, tissue, cell
Biosphere, ecosystem, community, population, organism