43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

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Chapter 28

Biomolecules - all with Video Answers

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Section 1

Topic 1 : Carbohydrates and Lipids

Problem 1

Which one of the following statements is not true? [Main Sep. 06, 2020 (II)]
(a) Lactose contains $\alpha$-glycosidic linkage between $\mathrm{C}_{1}$ of galactose and $\mathrm{C}_{4}$ of glucose.
(b) Lactose is a reducing sugar and it gives Fehling's test.
(c) Lactose $\left(\mathrm{C}_{11} \mathrm{H}_{22} \mathrm{O}_{11}\right)$ is a disaccharide and it contains 8 hydroxyl groups.
(d) On acid hydrolysis, lactose gives one molecule of $\mathrm{D}(+)$-glucose and one molecule of D(+)-galactose

Narayan Hari

Narayan Hari

Numerade Educator

Problem 2

What are the functional groups present in the structure of maltose? [Main Sep. 04, 2020 (I)]
(a) One ketal and hemiketal
(b) Two acetals
(c) One acetal and one hemiacetal
(d) One acetal and one ketal

Narayan Hari

Numerade Educator

Problem 3

Consider the following reactions:
[Main Sep. 02, 2020 (I)]
(i) Glucose $+\mathrm{ROH} \stackrel{\text { dry } \mathrm{HCl}}{\longrightarrow}$ Acetal $\frac{x \text { eq. of }}{\left(\mathrm{CH}_{3} \mathrm{CO}\right)_{2} \mathrm{O}}$ acetyl derivative
(ii) Glucose $\stackrel{\mathrm{Ni} / \mathrm{H}_{2}}{\longrightarrow} \mathrm{A} \frac{y \text { eq. of }}{\left(\mathrm{CH}_{3} \mathrm{CO}\right)_{2} \mathrm{O}}$ acetyl derivative
(iii) Glucose $\frac{z \text { eq. of }}{\left(\mathrm{CH}_{3} \mathrm{CO}\right)_{2} \mathrm{O}}$ acetyl derivative ' $x^{\prime}, y^{\prime}$ and ' $z^{\prime}$ in these reactions are respectively.
(a) $5,4 \& 5$
(b) $4,6 \& 5$
(c) $4,5 \& 5$
(d) $5,6 \& 5$

Maryam Riaz

Numerade Educator

Problem 4

The correct observation in the following reactions is :
Sucrose $\frac{\text { Glycosidic bond }}{\underset{\text { Cleavage }}{\longrightarrow}} \mathrm{A}+\mathrm{B} \frac{\text { Scliwanol } \mathrm{H}}{\text { (Hydrolysis) }} \frac{\text { reagent }}{\longrightarrow} ?$
[Main Sep. 02, 2020 (II)]
(a) Formation of blue colour
(b) Gives no colour
(c) Formation of red colour
(d) Formation of violet colour

Narayan Hari

Numerade Educator

Problem 5

Which of the following statement is not true for glucose? [Main Jan. 08, 2020 (I)]
(a) Glucose exists in two crystalline forms $\square$ and $\square$
(b) Glucose gives Schiff's test for aldehyde
(c) Glucose reacts with hydroxylamine to form oxime The pentaacetate of glucose does not
(d) react with hydroxylamine to give oxime

Narayan Hari

Numerade Educator

Problem 6

Two monomers in maltose are:
(a) $\square-\mathrm{D}$-glucose and $\square-\mathrm{D}$-glucose
(b) $\square-$ D-glucose and $\square-$ D-galactose
(c) $\square-\mathrm{D}$-glucose and $\square-\mathrm{D}$-fructose
(d) $\square-$ D-glucose and $\square-$ D-glucose

Maryam Riaz

Numerade Educator

Problem 7

Which of the following statements is correct? [Main Jan. 07, 2020 (II)]
(a) Gluconic acid can form cyclic (acetal/hemiacetal) structure
(b) Gluconic acid is a dicarboxylic acid
(c) Gluconic acid is a partial oxidation product of glucose
(d) Gluconic acid is obtained by oxidation of glucose with $\mathrm{HNO}_{3}$

Narayan Hari

Numerade Educator

Problem 8

Which of the given statements is INCORRECT about glycogen?
(a) It is a straight chain polymer similar to amylose.
(b) Only a-linkages are present in the molecule.
(c) It is present in animal cells.
(d) It is present in some yeast and fungi.

Maryam Riaz

Numerade Educator

Problem 9

Amylopectin is composed of :
(a) $\square-\mathrm{D}$-glucose, $\mathrm{C}_{1}-\mathrm{C}_{4}$ and $\mathrm{C}_{1}-\mathrm{C}_{6}$ linkages
(b) $\beta$-D-glucose, $\mathrm{C}_{1}-\mathrm{C}_{4}$ and $\mathrm{C}_{2}-\mathrm{C}_{6}$ linkages
(c) $\beta$-D-glucose, $\mathrm{C}_{1}-\mathrm{C}_{4}$ and $\mathrm{C}_{1}-\mathrm{C}_{6}$ linkages
(d) $\square$-D-glucose, $\mathrm{C}_{1}-\mathrm{C}_{4}$ and $\mathrm{C}_{2}-\mathrm{C}_{6}$ linkages

Maryam Riaz

Numerade Educator

Problem 10

Number of stereo centers present in linear and cyclic structures of glucose are respectively:
[Main April 10, 2019 (II)]
(a) $5 \& 4$
(b) $4 \& 4$
(c) $5 \& 5$
(d) $4 \& 5$

Maryam Riaz

Numerade Educator

Problem 11

Which of the following statements is not true about sucrose? [Main April 9, 2019 (I)]
(a) It is a non reducing sugar
(b) The glycosidic linkage is present between $\mathrm{C}_{1}$ of $\alpha$-glucose and $\mathrm{C}$ of $\beta-$ fructose
(c) It is also named as invert sugar
(d) On hydrolysis, it produces glucose and fructose

Maryam Riaz

Numerade Educator

Problem 12

Glucose on prolonged heating with HI gives :
(a) $n$-Hexane
(b) 1 - Hexene
(c) Hexanoic acid
(d) 6-iodohexanal

Narayan Hari

Numerade Educator

Problem 13

Among the following, the incorrect statement is:
[Main Online April 16, 2018]
(a) Cellulose and amylose have 1,4 -glycosidic linkage
(b) Lactose contains $\beta$-D-galactose and $\beta$-D-glucose
(c) Maltose and lactose have 1,4 -glycosidic linkage
(d) Sucrose and amylose have 1,2 -glycosidic linkage

Narayan Hari

Numerade Educator

Problem 14

Which of the following compounds will behave as a reducing sugar in an aqueous KOH solution?

Nidhi Singhi

Numerade Educator

Problem 15

The incorrect statement among the following is :
[Main Online April 9, 2017]
(a) $\alpha$-D-glucose and $\beta$-D-glucose are anomers.
(b) $\alpha$-D-glucose and $\beta$-D-glucose are enantiomers.
(c) Cellulose is a straight chain polysaccharide made up of only $\beta$-Dglucose units.
(d) The penta acetate of glucose does not react with hydroxyl amine.

Maryam Riaz

Numerade Educator

Problem 16

Accumulation of which of the following molecules in the muscles occurs as a result of vigorous exercise?
(a) Glycogen
(b) Glucose
(c) Pyruvic acid
(d) L-lactic acid

Narayan Hari

Numerade Educator

Problem 17

Complete hydrolysis of starch gives :
(a) glucose only [Main Online April 10, 2015]
(b) galactose and fructose in equimolar amounts
(c) glucose and galactose in equimolar amounts
(d) glucose and fructose in equimolar amounts

Narayan Hari

Numerade Educator

Problem 18

Which of the following will not show mutarotation? [Main Online April 12, 2014]
(a) Maltose
(b) Lactose
(c) Glucose
(d) Sucrose

Narayan Hari

Numerade Educator

Problem 19

Synthesis of each molecule of glucose in photosynthesis involves :
[Main 2013]
(a) 18 molecules of ATP
(b) 10 molecules of ATP
(c) 8 molecules of ATP
(d) 6 molecules of ATP

Narayan Hari

Numerade Educator

Problem 20

Which of the following statement is not correct? [Main Online April 25, 2013]
(a) Amylopectin is a branched polymer of $\alpha$-glucose.
(b) Cellulose is a linear polymer of $\beta$-glucose
(c) Glycogen is the food reserve of plants
(d) All proteins are polymers of $\alpha$-amino acids.

Narayan Hari

Numerade Educator

Problem 21

Natural glucose is termed D-glucose because :
[Main Online April 23, 2013]
(a) $-\mathrm{OH}$ on the second carbon is on the right side in Fischer projection
(b) $-\mathrm{OH}$ on the sixth carbon is on the right side in Fischer projection.
(c) $-\mathrm{OH}$ on the fifth carbon is on the right side in Fischer projection.
(d) It is dextrorotatory.

Narayan Hari

Numerade Educator

Problem 22

The following carbohydrate is
(a) a ketohexose
(c) an $\alpha$-furanose
(d) an $\alpha$-pyranose

Nidhi Singhi

Numerade Educator

Problem 23

The correct statement about the following disaccharide is
[2010]
(a) Ring $(\mathbf{A})$ is pyranose with $\alpha$-glycosidic link
(b) Ring (A) is furanose with $\alpha$-glycosidic link
(c) Ring $(\mathbf{B})$ is furanose with $\alpha$-glycosidic link
(d) Ring $(\mathbf{B})$ is pyranose with $\beta$ - glycosidic link

Nidhi Singhi

Numerade Educator

Problem 24

Cellulose upon acetylation with excess acetic anhydride/H $_{2} \mathrm{SO}_{4}$ (catalytic) gives cellulose triacetate whose structure is

Nidhi Singhi

Numerade Educator

Problem 25

The two forms of D-glucopyranose obtained from the solution of D-glucose are called [2005S]
(a) Isomers
(b) Anomers
(c) Epimers
(d) Enantiomers

Narayan Hari

Numerade Educator

Problem 26

The pair of compounds in which both the compounds give positive test with Tollen's reagent is [2004S]
(a) Glucose and Sucrose
(b) Fructose and Sucrose
(c) Acetophenone and Hexanal
(d) Glucose and Fructose

Narayan Hari

Numerade Educator

Problem 27

When the following aldohexose exists in its D-configuration, the total number of stereoisomers in its pyranose form is :
$\mathrm{CHO}-\mathrm{CH}_{2}-\mathrm{CHOH}-\mathrm{CHOH}-\mathrm{CHOH}-\mathrm{CH}_{2} \mathrm{OH}$

Nidhi Singhi

Numerade Educator

Problem 28

The number of chiral carbons present in sucrose is

Nidhi Singhi

Numerade Educator

Problem 29

Which of the following statement(s) is (are) true? [Adv. 2019]
(a) Oxidation of glucose with bromine water gives glutamic acid.
(b) Hydrolysis of sucrose gives dextrorotatory glucose and laevorotatory fructose.
(c) The two six-membered cyclic hemiacetal forms of $\mathrm{D}-(+)$ - glucose are called anomers.
(d) Monosaccharides cannot be hydrolysed to give poly-hydroxy aldehydes and ketones

Maryam Riaz

Numerade Educator

Problem 30

The Fischer presentation of D-glucose is given below. [Adv. 2018]
<smiles>OCC(O)C(O)C(O)CO</smiles> D-glucose The correct structure(s) of $\beta$-L-glucopyranose is (are)
(a)

Nidhi Singhi

Numerade Educator

Problem 31

For 'invert sugar', the correct statement(s) is(are) (Given: specific rotations of (+) -sucrose, (+)-maltose, L-(-)-glucose and L-(+) fructose in aqueous solution are+ $66^{\circ},+140^{\circ},-52^{\circ}$ and $+92^{\circ}$, respectively)
(a) 'invert sugar' is prepared by acid catalyzed hydrolysis of maltose
(b) 'invert sugar' is an equimolar mixture of D-(+)-glucose and D-(-)fructose
(c) specific rotation of 'invert sugar' is $-20^{\circ}$
(d) on reaction with $\mathrm{Br}_{2}$ water, 'invert sugar' forms saccharic acid as one of the products

Nidhi Singhi

Numerade Educator

Problem 32

The structure of $\mathrm{D}-(+)$-glucose is
The structure of $L-(-)$-glucose is
(a)
<smiles>O=CC(O)C(O)C(O)C(O)CO</smiles>
<smiles>O=CC(O)C(O)C(O)C(O)CO</smiles>
(c)
<smiles>O=CC(O)C(O)C(O)C(O)CO</smiles>

Maryam Riaz

Numerade Educator

Problem 33

The correct statement(s) about the following sugars $\mathbf{X}$ and $\mathbf{Y}$ is (are) [2009S]
$\mathbf{Y}$
(a) $\mathbf{X}$ is a reducing sugar and $\mathbf{Y}$ is a non-reducing sugar
(b) $\mathbf{X}$ is a non-reducing sugar and $\mathbf{Y}$ is a reducing sugar
(c) The glucosidic linkages in $\mathbf{X}$ and $\mathbf{Y}$ are $\alpha$ and $\beta$, respectively
(d) The glucosidic linkages in $\mathbf{X}$ and $\mathbf{Y}$ are $\beta$ and $\alpha$, respectively

Nidhi Singhi

Numerade Educator

Problem 34

Match the following, choosing one item from column $\mathbf{X}$ and the appropriate item from column $\mathrm{Y}$. [1983 - 2 Marks]
(i) Lucas test
(a) Phenol
(ii) Neutral $\mathrm{FeCl}_{3}$ test
(b) Glucose
(iii) Dye test
(c) Tertiary alcohol
(iv) Tollen's test
(d) Aniline

Nikhil Choudhary

Nikhil Choudhary

Numerade Educator

Problem 35

This question contains Statement-1 (Assertion) and Statement-2 (Reason) and has 4 choices (a), (b), (c) and (d) out of which ONLY ONE is correct. Statement-1 : Glucose gives a reddish-brown precipitate with Fehling's solution. because Statement-2 : Reaction of glucose with Fehling's solution give $\mathrm{CuO}$ and gluconic acid. [2007]
(a) Statement-1 is True, Statement- 2 is True; Statement-2 is a correct explanation for Statement-1
(b) Statement-1 is True, Statement- 2 is True; Statement-2 is not a correct explanation for Statement-1
(c) Statement-1 is True, Statement- 2 is False
(d) Statement- 1 is False, Statement- 2 is True.

Narayan Hari

Numerade Educator

Problem 36

Which of the following will reduce Tollen's reagent? Explain.

Nidhi Singhi

Numerade Educator

Problem 37

The Fisher projection of D-glucose is drawn below. [2004 - 2 Marks]
<smiles>OCC(O)C(O)C(O)CO</smiles>
(i) Draw the Fisher projection of $L$-glucose.
(ii) Give the reaction of L-glucose with Tollen's reagent

Nidhi Singhi

Numerade Educator