287080
Which one of the following sets of monosaccharides forms sucrose?
1 \(\alpha\)-D-Galactopyranose and \(\alpha-\mathrm{D}\)-Glucopyranose
2 \(\alpha\)-D-Glucopyranose and \(\beta\)-D-Fructofuranose
3 \(\beta\)-D-Glucopyranose and \(\alpha-\mathrm{D}\) - Fructofuranose
4 \(\alpha\)-D-Glucopyranose and \(\beta\)-D-Fructopyranose
Explanation:
(b)
\(\alpha\)-D-Glucopyranose
\(\beta\)-D-Fructofuranose
Sucrose is a disaccharide of \(\alpha\)-D-Glucopyranose and \(\beta\)-D-Fructofuranose.
**NOTE**
The glycoside linkage is between C 1 of \(\alpha-\mathrm{D}\) glucose and C 2 of \(\beta\)-D-fructose.
NCERT | Page-417 / N-287| 2012
BIOMOLECULES (NEET PYQS)
287081
Which one of the following statements is not true regarding \((+)\) Lactose?
1 On hydrolysis ( + ) Lactose gives equal amount of \(\mathrm{D}(+)\) glucose and \(\mathrm{D}(+)\) galactose.
2 (+) Lactose is a \(\beta\)-glycoside formed by the union of a molecule of \(D(+)\) glucose and a molecule of \(\mathrm{D}(+)\) galactose.
3 (+) Lactose is a reducing sugar and does not exhibit mutarotation.
(c) All reducing sugar shows mutarotation.
**NOTE** Reducing sugars have hydroxyl group at the anomeric C1 position. In solution, a carbohydrate can open up to its aldehyde form. Hence, it can switch configuration between \(\alpha\)-and \(\beta\)-forms.
NCERT | Page-418 / N-288 | 2011
BIOMOLECULES (NEET PYQS)
287082
Which one of the following does not exhibit the phenomenon of mutarotation?
1 (+) - Sucrose
2 (+)-Lactose
3 (+) - Maltose
4 (-) - Fructose
Explanation:
(a) Sucrose does not have free - CHO or CO group, hence it does not undergo mutarotation.
NEET 2010
BIOMOLECULES (NEET PYQS)
287083
Fructose reduces Tollen's reagent due to
1 enolisation of fructose followed by conversion to aldehyde by base
2 asymmetric carbons
3 primary alcoholic group
4 secondary alcoholic group
Explanation:
(a) Fructose, a ketose as the substrate, under the alkaline medium of Tollen's reagent, a part of fructose is transformed into glucose and mannose, both aldoses. Then these aldoses give positive silver mirror test.
NEET Test Series from KOTA - 10 Papers In MS WORD
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BIOMOLECULES (NEET PYQS)
287080
Which one of the following sets of monosaccharides forms sucrose?
1 \(\alpha\)-D-Galactopyranose and \(\alpha-\mathrm{D}\)-Glucopyranose
2 \(\alpha\)-D-Glucopyranose and \(\beta\)-D-Fructofuranose
3 \(\beta\)-D-Glucopyranose and \(\alpha-\mathrm{D}\) - Fructofuranose
4 \(\alpha\)-D-Glucopyranose and \(\beta\)-D-Fructopyranose
Explanation:
(b)
\(\alpha\)-D-Glucopyranose
\(\beta\)-D-Fructofuranose
Sucrose is a disaccharide of \(\alpha\)-D-Glucopyranose and \(\beta\)-D-Fructofuranose.
**NOTE**
The glycoside linkage is between C 1 of \(\alpha-\mathrm{D}\) glucose and C 2 of \(\beta\)-D-fructose.
NCERT | Page-417 / N-287| 2012
BIOMOLECULES (NEET PYQS)
287081
Which one of the following statements is not true regarding \((+)\) Lactose?
1 On hydrolysis ( + ) Lactose gives equal amount of \(\mathrm{D}(+)\) glucose and \(\mathrm{D}(+)\) galactose.
2 (+) Lactose is a \(\beta\)-glycoside formed by the union of a molecule of \(D(+)\) glucose and a molecule of \(\mathrm{D}(+)\) galactose.
3 (+) Lactose is a reducing sugar and does not exhibit mutarotation.
(c) All reducing sugar shows mutarotation.
**NOTE** Reducing sugars have hydroxyl group at the anomeric C1 position. In solution, a carbohydrate can open up to its aldehyde form. Hence, it can switch configuration between \(\alpha\)-and \(\beta\)-forms.
NCERT | Page-418 / N-288 | 2011
BIOMOLECULES (NEET PYQS)
287082
Which one of the following does not exhibit the phenomenon of mutarotation?
1 (+) - Sucrose
2 (+)-Lactose
3 (+) - Maltose
4 (-) - Fructose
Explanation:
(a) Sucrose does not have free - CHO or CO group, hence it does not undergo mutarotation.
NEET 2010
BIOMOLECULES (NEET PYQS)
287083
Fructose reduces Tollen's reagent due to
1 enolisation of fructose followed by conversion to aldehyde by base
2 asymmetric carbons
3 primary alcoholic group
4 secondary alcoholic group
Explanation:
(a) Fructose, a ketose as the substrate, under the alkaline medium of Tollen's reagent, a part of fructose is transformed into glucose and mannose, both aldoses. Then these aldoses give positive silver mirror test.
287080
Which one of the following sets of monosaccharides forms sucrose?
1 \(\alpha\)-D-Galactopyranose and \(\alpha-\mathrm{D}\)-Glucopyranose
2 \(\alpha\)-D-Glucopyranose and \(\beta\)-D-Fructofuranose
3 \(\beta\)-D-Glucopyranose and \(\alpha-\mathrm{D}\) - Fructofuranose
4 \(\alpha\)-D-Glucopyranose and \(\beta\)-D-Fructopyranose
Explanation:
(b)
\(\alpha\)-D-Glucopyranose
\(\beta\)-D-Fructofuranose
Sucrose is a disaccharide of \(\alpha\)-D-Glucopyranose and \(\beta\)-D-Fructofuranose.
**NOTE**
The glycoside linkage is between C 1 of \(\alpha-\mathrm{D}\) glucose and C 2 of \(\beta\)-D-fructose.
NCERT | Page-417 / N-287| 2012
BIOMOLECULES (NEET PYQS)
287081
Which one of the following statements is not true regarding \((+)\) Lactose?
1 On hydrolysis ( + ) Lactose gives equal amount of \(\mathrm{D}(+)\) glucose and \(\mathrm{D}(+)\) galactose.
2 (+) Lactose is a \(\beta\)-glycoside formed by the union of a molecule of \(D(+)\) glucose and a molecule of \(\mathrm{D}(+)\) galactose.
3 (+) Lactose is a reducing sugar and does not exhibit mutarotation.
(c) All reducing sugar shows mutarotation.
**NOTE** Reducing sugars have hydroxyl group at the anomeric C1 position. In solution, a carbohydrate can open up to its aldehyde form. Hence, it can switch configuration between \(\alpha\)-and \(\beta\)-forms.
NCERT | Page-418 / N-288 | 2011
BIOMOLECULES (NEET PYQS)
287082
Which one of the following does not exhibit the phenomenon of mutarotation?
1 (+) - Sucrose
2 (+)-Lactose
3 (+) - Maltose
4 (-) - Fructose
Explanation:
(a) Sucrose does not have free - CHO or CO group, hence it does not undergo mutarotation.
NEET 2010
BIOMOLECULES (NEET PYQS)
287083
Fructose reduces Tollen's reagent due to
1 enolisation of fructose followed by conversion to aldehyde by base
2 asymmetric carbons
3 primary alcoholic group
4 secondary alcoholic group
Explanation:
(a) Fructose, a ketose as the substrate, under the alkaline medium of Tollen's reagent, a part of fructose is transformed into glucose and mannose, both aldoses. Then these aldoses give positive silver mirror test.
287080
Which one of the following sets of monosaccharides forms sucrose?
1 \(\alpha\)-D-Galactopyranose and \(\alpha-\mathrm{D}\)-Glucopyranose
2 \(\alpha\)-D-Glucopyranose and \(\beta\)-D-Fructofuranose
3 \(\beta\)-D-Glucopyranose and \(\alpha-\mathrm{D}\) - Fructofuranose
4 \(\alpha\)-D-Glucopyranose and \(\beta\)-D-Fructopyranose
Explanation:
(b)
\(\alpha\)-D-Glucopyranose
\(\beta\)-D-Fructofuranose
Sucrose is a disaccharide of \(\alpha\)-D-Glucopyranose and \(\beta\)-D-Fructofuranose.
**NOTE**
The glycoside linkage is between C 1 of \(\alpha-\mathrm{D}\) glucose and C 2 of \(\beta\)-D-fructose.
NCERT | Page-417 / N-287| 2012
BIOMOLECULES (NEET PYQS)
287081
Which one of the following statements is not true regarding \((+)\) Lactose?
1 On hydrolysis ( + ) Lactose gives equal amount of \(\mathrm{D}(+)\) glucose and \(\mathrm{D}(+)\) galactose.
2 (+) Lactose is a \(\beta\)-glycoside formed by the union of a molecule of \(D(+)\) glucose and a molecule of \(\mathrm{D}(+)\) galactose.
3 (+) Lactose is a reducing sugar and does not exhibit mutarotation.
(c) All reducing sugar shows mutarotation.
**NOTE** Reducing sugars have hydroxyl group at the anomeric C1 position. In solution, a carbohydrate can open up to its aldehyde form. Hence, it can switch configuration between \(\alpha\)-and \(\beta\)-forms.
NCERT | Page-418 / N-288 | 2011
BIOMOLECULES (NEET PYQS)
287082
Which one of the following does not exhibit the phenomenon of mutarotation?
1 (+) - Sucrose
2 (+)-Lactose
3 (+) - Maltose
4 (-) - Fructose
Explanation:
(a) Sucrose does not have free - CHO or CO group, hence it does not undergo mutarotation.
NEET 2010
BIOMOLECULES (NEET PYQS)
287083
Fructose reduces Tollen's reagent due to
1 enolisation of fructose followed by conversion to aldehyde by base
2 asymmetric carbons
3 primary alcoholic group
4 secondary alcoholic group
Explanation:
(a) Fructose, a ketose as the substrate, under the alkaline medium of Tollen's reagent, a part of fructose is transformed into glucose and mannose, both aldoses. Then these aldoses give positive silver mirror test.
