Multiple choice questions 16. Which of the following terms does NOT refer to all
ID: 175700 • Letter: M
Question
Multiple choice questions
16. Which of the following terms does NOT refer to allosteric regulation?
a. feedback inhibition
b. competitive inhibition
c. allosteric activation
d. reversible inhibition
e. enzyme shape
17. The substance on which an enzyme acts is called the
a. free energy.
b. cofactor.
c. substrate.
d. product.
e. ATP.
18. Which of the following statements concerning activation energy is FALSE?
a. Catalysts raise a reaction’s activation energy.
b. Activation energy is the energy required to break existing bonds.
c. Endergonic reactions have an energy of activation.
d. Exergonic reactions have an energy of activation.
e. Enzymes lower a reaction’s activation energy.
19. With increasing temperatures, the rate of an enzyme-catalyzed reaction
a. does not change.
b. increases and then levels off.
c. increases and then decreases rapidly.
d. decreases and then increases rapidly.
e. decreases and then levels off.
21. During chemiosmosis in the mitochondria, ATP is produced as
a. protons are pumped by ATP synthase into the mitochondrial matrix.
b. cytochrome is reduced.
c. oxygenthe final electron acceptoris reduced.
d. NADH is oxidized to NAD+.
e. none of the above
22. What is the immediate fate of the electrons in NADH during fermentation?
a. They are used to make CO2.
b. They are used to form H2O.
c. They are transferred to an organic molecule.
d. They are transferred to O2.
e. They are transferred to the electron transport chain.
23. Which of the following statements about lactic acid fermentation is NOT correct?
a. It produces two ATP molecules for every glucose molecule.
b. It is inefficient compared to aerobic respiration.
c. Oxygen is the final electron acceptor of this pathway.
d. It uses glucose as a substrate.
e. Glycolysis is the only energy-yielding step of this pathway.
24. Which of the following steps in the citric acid cycle directly produces a molecule of GTP?
a. citrate isocitrate
b. isocitrate -ketoglutarate
c. succinyl CoA succinate
d. malate oxaloacetate
e. succinate fumarate
25. In glycolysis, the activity of ________ is controlled through feedback inhibition by ________.
a. phosphofructokinase; ATP
b. phosphoglucoisomerase; AMP
c. pyruvate dehydrogenase; oxaloacetate
d. phosphofructokinase; AMP
e. phosphoglucoisomerase; glucose-6-phosphate
26. Red and blue light support the highest rates of photosynthesis because
a. these wavelengths activate the ATP synthase enzyme.
b. these are the only wavelengths that carotenoids cannot absorb.
c. these wavelengths have the highest energy in the visible spectrum.
d. chlorophyll absorbs these wavelengths more than other wavelengths.
e. these are the only wavelengths reaching Earth from the Sun.
27. Which of the following applies to cyclic electron transport but does NOT to apply to acyclic electron transport?
a. Protons are moved into the thylakoid lumen.
b. production of ATP, but not NADPH
c. production of both ATP and NADPH
d. photolysis
e. P680
28. Which of the following may happen AFTER an electron is induced by a photon?
a. The electron may accept another photon.
b. A neighbouring pigment molecule donates energy to the electron.
c. The electron returns to ground level while keeping its high energy.
d. The electron releases energy as heat as it moves back to ground level.
e. all of the above
29. Which of the following is common to both photosynthesis and aerobic respiration?
a. the Calvin cycle
b. glycolysis
c. CO2 and O2 as end products
d. thylakoids
e. chemiosmosis
30. Chlorophyll absorbs primarily ________ and ________ regions of the visible spectrum.
a. red; yellow
b. red; green
c. blue; yellow
d. green; yellow
e. blue; red
Explanation / Answer
16. Allosteric regulation is the regulation of enzyme by an effector molecule by binding to it oj the site ither than active site of it.
Option E is the correct answer.
All other are the processes whih in some or the other way regulates the activity of the enzyme this are related to allosteric regulation. But enzyme shape is not a process. Though it is relevant for allosteric regulation. But this term in particular does not refer to the allosteric regulation.
17. Option C ie the correct answer. As substrate are the molecules on which enzymes act. They differ from enzyme to enzyme. Fir example for amylase it's carbohydrate, for lipase it's fats.. etc.
18. Activation energy is the minimum energy which the reacting agents must possess for the reaction to occur.
Option A is the wrong statement as catalysts are the ones which decrease the activation energy to make reaction faster.
19. option C is the correct answer. As with increasing temperature activity increases. When it reaches upto optimum and temperature is further increased then enzyme gets denatured and thus activity decreases abruptly.
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