Question

Hydroxylamine lowers catalase activity by fitting within its active site. This suggest that

Select one:

a. Hydroxylamine is most likely the main substrate of catalase

b. Hydroxylamine is a competitive inhibitor of catalase

c. Hydroxylamine is an allosteric inhibitor of catalase

d. Hydroxylamine is an allosteric activator of catalase

e. Hydroxylamine has the ability to denature catalase

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Based on cellular respiration only, would you have to breathe if your cells did not have mitochondria?

Select one:

a. No

b. Yes

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At the beginning of the electron transport chain in mitochondria, NADH releases

Select one:

a. 1 electron and 1 proton

b. 2 electrons and 1 proton

c. 1 electron and 2 protons

d. 2 electrons and 2 protons

Answer 1

Hydroxylamine lowers catalase activity by fitting within its active site. This suggest that b. Hydroxylamine is a competitive inhibitor of catalase. Competitive inhibitors bind to the active site and prevent substrate binding reducing the activity of the enzyme. Since Hydroxylamine binds to the active site it cannot be an allosteric activator or inhibitor which can only bind to the allosteric site. Again, it is not the substate of catalase but hydrogen peroxide is the substrate of catalase. Denatuartion would completely remove any activity of the enzyme however here it is said that the activity is inhibited or reduced. Therefore, since Hydroxylamine reduces the activity of catalase by binding to the active site it is a competitive inhibitor.

Based on cellular respiration only, we would not have to breathe if our cells did not have mitochondria. So thw correct option is a. No.This is because only kreb cycle and ETC occurs in the presence of oxygen in the mitochondria. Glycolysis is majorly anerobic and without oxygen, cells can produce ATP by lactic acid fermentation as in yeast and muscle cells. Thus without mitochondria, there is no need for oxygen in cellular respiration.

At the beginning of the electron transport chain in mitochondria, NADH releases c. 1 electron and 2 protons. This is because NADH transports a total of 2 e- to CoQ and pumps a total of 4 H+ across the inner mitochondrial membrane. So the likely option that matches is 1 electron per 2 protons (H+).

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