Question

Question 24 (1 point) Which of the following enzymes does not catalyze a reaction in which carbon dioxide (CO2) is released? O Alpha-ketoglutarate dehydrogenase Pyruvate dehydrogenase Malate dehydrogenase Isocitrate dehydrogenase Question 25 (1 point) The acute toxicity of cyanide to mammals is primarily caused by its ... O inhibition of cytochrome oxidase. O action as an uncoupler of oxidative phosphorylation. O inhibition of complex I of the electron transport chain. O inhibition of the citric acid cycle enzyme succinate dehydrogenase,

Answer 1

Question 24

Ans Malate dehydrogenase

because (MDH) is an enzyme that reversibly catalyzes the oxidation of malate to oxaloacetate using the reduction of NAD+ to NADH. This reaction is part of many metabolic pathways, including the citric acid cycle. It dose not catalyse reaction in which CO2 evolve.

Question 25

+ NAD + NADH + H Malate Dehydrogenase L-Malate Oxaloacetate

Ans Inhibition of cytochrome oxidase in the bloodstream, cyanide forms a stable complex with a form of cytochrome oxidase, an enzyme that promotes the transfer of electrons in the mitochondria of cells during the synthesis of ATP. Without proper cytochrome oxidase function, cells cannot utilize the oxygen present in the bloodstream, resulting in cytotoxic hypoxia or cellular asphyxiation. The lack of available oxygen causes a shift from aerobic to anaerobic metabolism, leading to the accumulation of lactate in the blood. The combined effect of the hypoxia and lactate acidosis is depression of the central nervous system that can result in respiratory arrest and death.