Biochemistry-I MCQs | BIO202 MCQs | Set 7
Biochemistry-I MCQs | BIO202 MCQs | Set 7
MCQs (Multiple Choice Questions)
1) Choose a suger out of the following that is non reactive to Seliwanoff reagent?
a) Sucrose
b) Fructose
c) Inulin
d) Ribose
Correct Answer:
The correct answer is 'd'.
Explanation:
Seliwanoff's reagent is used to distinguish between ketose and aldose sugars. Ketose sugars react with Seliwanoff's reagent to produce a cherry-red color, while aldose sugars do not react.
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2) Choose a keto triose:
a) Glyceraldehyde
b) Dihydroxyacetone
c) Erythrose
d) Arabinose
Correct Answer:
The correct answer is 'b'.
Explanation:
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3) A pentose sugar present in the heart muscle is:
b) Xylulose
c) Lyxose
d) Aldose
Correct Answer:
The correct answer is 'c'.
Explanation:
Lyxose is a pentose sugar that can be found in various tissues, including the heart muscle. It is an aldose, which means it is a sugar with an aldehyde functional group.
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4) d-Glucose and I-Glucose are:
a) Stereo isomers
b) Anomers
c) Keto-Aldose
d) Optical isomers
Correct Answer:
The correct answer is 'd'.
Explanation:
d-Glucose and l-Glucose are optical isomers, also known as enantiomers. They have the same chemical formula but differ in their three-dimensional spatial arrangement, making them non-superimposable mirror images of each other. Stereoisomers are a broader category that includes enantiomers, diastereomers, and others. Anomers refer to specific types of stereoisomers related to the cyclic structure of sugars.
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5) All the following tests are positive for Lactose except ________.
a) Benedict
b) Barfoed
c) Molisch
d) Osazone
Correct Answer:
The correct answer is 'd'.
Explanation:
The osazone test is used to identify monosaccharides, such as glucose and fructose. Lactose is a disaccharide made up of glucose and galactose. Therefore, lactose will not give a positive osazone test.
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6) Glucose can have _____ isomers due to the presence of 4 asymmetric carbon atoms.
a) 4
b) 2
c) 12
d) 16
Correct Answer:
The correct answer is 'd'.
Explanation:
Glucose can have 16 stereoisomers due to the presence of 4 asymmetric (chiral) carbon atoms. Each chiral carbon can have two possible configurations (R and S), and when you multiply the possibilities for all four chiral carbons, you get a total of `2^4` = 16 stereoisomers.
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7) Fructose and Ribulose are:
a) Epimers
b) Anomers
c) Ketoses
d) Ketose-Aldose isomers
Correct Answer:
The correct answer is 'c'.
Explanation:
Ketoses are monosaccharides that have a ketone functional group. Fructose and ribulose are both ketoses.
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8) The compounds having same structural formula but differing in configuration around one carbon atom are called:
a) Optical isomers
b) Anomers
c) Stereo isomers
d) Epimers
Correct Answer:
The correct answer is 'd'.
Explanation:
The compounds having the same structural formula but differing in configuration around one carbon atom are called epimers. Epimers are a type of stereoisomer and are characterized by their differences at a single chiral center. Anomers are a specific type of epimer related to the cyclic structure of sugars. Stereoisomers is a broader term that encompasses various types of isomers that differ in their spatial arrangement. Optical isomers (enantiomers) are a subtype of stereoisomers.
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9) What does the following equation represent?
`alpha`-D Glucose + 112o`\rightarrow`+52.5o`\rightarrow`+19o`\beta` - D glucose
a) Stereois omerism
b) Optical isomerism
c) Mutarotion
d) Epimerization
Correct Answer:
The correct answer is 'c'.
Explanation:
The equation represents mutarotation, which is a phenomenon in which the specific rotation (observed optical rotation) of an optically active compound changes over time when dissolved in a solvent. In this case, it's referring to the mutarotation of α-D-glucose to β-D-glucose, where the specific rotation values change as the glucose solution shifts between the α and β forms. Mutarotation is a characteristic of compounds that can exist in different anomeric forms (such as α and β) and is a type of optical isomerism.
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10) The carbohydrate of honey is
a) Fucose
b) Maltose
c) Lactose
d) Fructose
Correct Answer:
The correct answer is 'd'.
Explanation:
Fructose is a monosaccharide, which means that it is the simplest form of carbohydrate. It is a ketose sugar, which means that it has a ketone functional group. Fructose is one of the sweetest sugars, and it is responsible for the sweetness of honey.
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