NURSING EXAM QUESTIONS
BIOCHEMISTRY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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biological activity.
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chiral activity.
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racemization.
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stereoisomerization.
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stereospecificity.
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Detailed explanation-1: -The enzyme fumarase catalyzes the reversible hydration of fumaric acid to l-malate, but it will not catalyze the hydration of maleic acid, the cis isomer of fumaric acid. This is an example of: A. biological activity.
Detailed explanation-2: -This enzyme belongs to the family of lyases, specifically the hydro-lyases, which cleave carbon-oxygen bonds. The systematic name of this enzyme class is (S)-malate hydro-lyase (fumarate-forming). Other names in common use include: fumarase.
Detailed explanation-3: -Answer and Explanation: The enzyme responsible for the conversion of fumarate to malate is fumarase, or fumarate hydratase. The enzyme catalyzes the reversible process of fumarate to malate via hydration/dehydration reactions.
Detailed explanation-4: -The key difference between maleic acid and fumaric acid is that maleic acid is the cis-isomer of butenedioic acid, whereas fumaric acid is the trans-isomer. Moreover, maleic acid forms weak intramolecular hydrogen bonds and has a much lower melting point than fumaric acid.
Detailed explanation-5: -Therefore, the correct answers are an option (a)-Fumaric acid shows intermolecular H-bonding and (d)-Maleic acid shows chelation or intermolecular H-bonding. Note: The maleic acid or the cis-form of butenedioic acid is less stable than the Fumaric acid or the trans form of butenedioic acid.