MCQ Collection
MDCAT Biology MCQs
Practice MDCAT Biology questions with answers and explanations.
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Correct Answer: B. Activity rises to an optimum and then may fall as the enzyme denatures
Explanation:
Warming increases molecular collisions up to an optimum.
Excess heat disrupts enzyme structure.
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Correct Answer: B. Cytoplasm
Explanation:
Glycolysis breaks glucose into pyruvate.
It occurs in the cytosol and does not directly require oxygen.
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Correct Answer: C. Activity rises to an optimum and then may fall as the enzyme denatures
Explanation:
Warming increases molecular collisions up to an optimum.
Excess heat disrupts enzyme structure.
Choose an option to check your answer.
Correct Answer: C. Cytoplasm
Explanation:
Glycolysis breaks glucose into pyruvate.
It occurs in the cytosol and does not directly require oxygen.
Choose an option to check your answer.
Correct Answer: D. Activity rises to an optimum and then may fall as the enzyme denatures
Explanation:
Warming increases molecular collisions up to an optimum.
Excess heat disrupts enzyme structure.
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Correct Answer: D. To transfer energy from organic molecules into ATP
Explanation:
Cellular respiration oxidizes fuel molecules.
Most ATP in aerobic cells is produced through oxidative phosphorylation.
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Correct Answer: A. Each enzyme has an optimal pH range
Explanation:
PH alters ionization of amino-acid side chains.
Extreme pH can reduce activity or denature enzymes.
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Correct Answer: B. Each enzyme has an optimal pH range
Explanation:
PH alters ionization of amino-acid side chains.
Extreme pH can reduce activity or denature enzymes.
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Correct Answer: C. Each enzyme has an optimal pH range
Explanation:
PH alters ionization of amino-acid side chains.
Extreme pH can reduce activity or denature enzymes.
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Correct Answer: D. An inhibitor competes with substrate for the active site
Explanation:
Competitive inhibitors resemble or obstruct the substrate.
Their effect can often be reduced by increasing substrate concentration.
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Correct Answer: A. An inhibitor competes with substrate for the active site
Explanation:
Competitive inhibitors resemble or obstruct the substrate.
Their effect can often be reduced by increasing substrate concentration.
Choose an option to check your answer.
Correct Answer: A. A lipid with a hydrophilic head and hydrophobic tails
Explanation:
Phospholipids spontaneously form bilayers in water.
They are the main structural molecules of cell membranes.
