Biomolecules · JEE Main previous year questions

The incorrect statement from the following with respect to carbohydrates is :

1. A.All monosaccharides are reducing sugars.
2. B.The monosaccharide units obtained from hydrolysis of oligosaccharides are always the same.
3. C.Starch and cellulose are typical examples of polysaccharides, which are very high molecular weight compounds of more than ten monosaccharide units.
4. D.Open chain and cyclic structures co-exist at equilibrium that are responsible for certain properties as in the case of $\mathrm{D}-(+)-\mathrm{glucose}$.

Which of the following amino acid will give violet coloured complex with neutral ferric chloride solution ?

1. A.Threonine
2. B.Serine
3. C.Tyrosine
4. D.Cysteine

Match the LIST-I with LIST-II $$\begin{array}{llll}\text{List-I}& & \text{List-II}& \\ \text{Deficiency Disease}& & \text{Vitamin}& \\ \text{A.}& \text{Scurvy}& \text{I.}& \text{Pyridoxine}\\ \text{B.}& \text{Convulsions}& \text{II.}& \text{Vitamin A}\\ \text{C.}& \text{Cheilosis}& \text{III.}& \text{Ascorbic Acid}\\ \text{D.}& \text{Xerophthalmia}& \text{IV.}& \text{Riboflavin}\end{array}$$ Choose the correct answer from the options given below:

1. A.A-I, B-III, C-II, D-IV
2. B.A-I, B-III, C-IV, D-II
3. C.A-III, B-I, C-IV, D-II
4. D.A-III, B-I, C-II, D-IV

Sucrose hydrolyses in acidic medium into glucose and fructose by first order rate law with $t_{1/2}=3\mathrm{hour}$. The percentage of sucrose remaining after $6\mathrm{hours}$ is ____. (Nearest integer) (Given : $\log 2=0.3010$ and $\log 3=0.4771$)

Identify the correct statements. A. Glucose exists in two anomeric forms. B. Anomers of glucose differ in configuration at C–1 in cyclic hemiacetal structure. C. Melting point of $\alpha$ - anomer of glucose is greater than $\beta$ - anomer. D. Specific rotation of $\alpha$ - anomer is $+19^{\circ }$ while for $\beta$ - anomer is $+112^{\circ }$ E. $\alpha$ and $\beta$ - anomers of glucose are prepared by crystallization of saturated glucose solution at $303\text{ K}$ and $371\text{ K}$ respectively. Choose the correct answer from the options given below:

1. A.A and B Only
2. B.B and C Only
3. C.A, B and D Only
4. D.A, B and E Only

Identify the $\underline{\text{incorrect}}$ statement about tertiary structure of proteins.

1. A.They can be fibrous or globular in structure.
2. B.The main forces that stabilize the structure are hydrogen bonding, disulphide links, van der Waals and electrostatic forces of attraction.
3. C.The structure remains intact when exposed to $\mathrm{pH}$ changes.
4. D.A linear polypeptide chain will convert to a secondary structure and then further folding of the secondary structure will convert to tertiary structure.

1. A.Both Statement I and Statement II are true
2. B.Both Statement I and Statement II are false
3. C.Statement I is true but Statement II is false
4. D.Statement I is false but Statement II is true

1. A.Both Statement I and Statement II are true
2. B.Both Statement I and Statement II are false
3. C.Statement I is true but Statement II is false
4. D.Statement I is false but Statement II is true

Match the LIST-I with LIST-II $$\begin{array}{llll}& \text{List-I}& & \text{List-II}\\ & \text{Name of amino acid}& & \text{One letter symbol/type}\\ \text{A.}& \text{Arginine}& \text{I.}& \text{D/Non-essential}\\ \text{B.}& \text{Aspartic acid}& \text{II.}& \text{R/Essential}\\ \text{C.}& \text{Lysine}& \text{III.}& \text{E/Non-essential}\\ \text{D.}& \text{Glutamic acid}& \text{IV.}& \text{K/Essential}\end{array}$$ Choose the correct answer from the options given below:

1. A.A-II, B-I, C-IV, D-III
2. B.A-IV, B-III, C-II, D-I
3. C.A-III, B-IV, C-I, D-II
4. D.A-II, B-IV, C-I, D-III

Identify the correct pair having amino acid (A) and the hormone (B) that is iodinated derivative of the amino acid (A). (T and Y represent one letter code for amino acids) Amino acid (A) Hormone (B)

1. A.T Insulin
2. B.T Thyroxine
3. C.Y Thyroxine
4. D.Y Insulin

1. A.(Y) Serine (Sequence) Thr-Ser-Asp-Ala-Gly
2. B.(Y) Serine (Sequence) Ser-Asp-Thr-Ala-Gly
3. C.(Y) Threonine (Sequence) Ser-Thr-Asp-Gly-Ala
4. D.(Y) Threonine (Sequence) Thr-Ser-Asp-Gly-Ala

Consider the following aqueous solutions. I. 2.2 g Glucose in 125 mL of solution. II. 1.9 g Calcium chloride in 250 mL of solution. III. 9.0 g Urea in 500 mL of solution. IV. 20.5 g Aluminium sulphate in 750 mL of solution. The correct increasing order of boiling point of these solutions will be : [Given : Molar mass in ${\text{g mol}}^{-1}$ : $\text{H}=1,\text{C}=12,\text{N}=14,\text{O}=16,\text{Cl}=35.5,\text{Ca}=40,\text{Al}=27$ and $\text{S}=32$]

1. A.III < I < II < IV
2. B.II < III < IV < I
3. C.II < III < I < IV
4. D.I < II < III < IV

Given below are two statements : Statement I : Sublimation is used for the separation and purification of compounds with low melting point. Statement II : The boiling point of a liquid increases as the external pressure is reduced. In the light of the above statements, choose the correct answer from the options given below :

1. A.Both Statement I and Statement II are false
2. B.Statement I is true but Statement II is false
3. C.Both Statement I and Statement II are true
4. D.Statement I is false but Statement II is true

Both human DNA and RNA are chiral molecules. The chirality in DNA and RNA arises due to the presence of

1. A.L-sugar component
2. B.D-sugar component
3. C.Chiral phosphate unit
4. D.Base unit

Given below are two statements : Statement I : Sucrose is dextrorotatory. However, sucrose upon hydrolysis gives a solution having mixture of products. This solution shows laevorotation. Statement II : Hydrolysis of sucrose gives glucose and fructose. Since the laevorotation of glucose is more than the dextrorotation of fructose, the resulting solution becomes laevorotatory. In the light of the above statements, choose the correct answer from the options given below :

1. A.Both Statement I and Statement II are false
2. B.Both Statement I and Statement II are true
3. C.Statement I is true but Statement II is false
4. D.Statement I is false but Statement II is true

Identify the correct statements. A. Arginine and Tryptophan are essential amino acids. B. Histidine does not contain heterocyclic ring in its structure. C. Proline is a six membered cyclic ring amino acid. D. Glycine does not have chiral centre. E. Cysteine has characteristic feature of side chain as $\mathrm{MeS}-\mathrm{C}{\mathrm{H}}_2-\mathrm{C}{\mathrm{H}}_2-$. Choose the correct answer from the options given below :

1. A.C and D Only
2. B.A and D Only
3. C.C and E Only
4. D.B and E Only

The correct statements are : A. Activation energy for enzyme catalysed hydrolysis of sucrose is lower than that of acid catalysed hydrolysis. B. During denaturation, secondary and tertiary structures of a protein are destroyed but primary structure remains intact. C. Nucleotides are joined together by glycosidic linkage between ${\mathrm{C}}_1$ and ${\mathrm{C}}_4$ carbons of the pentose sugar. D. Quaternary structure of proteins represents overall folding of the polypeptide chain. Choose the correct answer from the options given below :

1. A.A, B and D Only
2. B.A, C and D Only
3. C.B and C Only
4. D.A and B Only

The total number of hydrogen bonds of a DNA-double Helix strand whose one strand has the following sequence of bases is ____. $5^{\prime }-\mathrm{G}-\mathrm{G}-\mathrm{C}-\mathrm{A}-\mathrm{A}-\mathrm{A}-\mathrm{T}-\mathrm{C}-\mathrm{G}-\mathrm{G}-\mathrm{C}-\mathrm{T}-\mathrm{A}-3^{\prime }$

1. A.alanine-alanine
2. B.valine-glycine
3. C.valine-leucine
4. D.alanine-glycine

1. A.
2. B.
3. C.
4. D.

Given below are two statements: Statement I : Wet cotton clothes made of cellulose based carbohydrate takes comparatively longer time to get dried than wet nylon polymer based clothes. Statement II : Intermolecular hydrogen bonding with water molecule is more in nylon-based clothes than in the case of cotton clothes. In the light of above statements, choose the correct answer from the options given below

1. A.Both Statement I and Statement II are false
2. B.Both Statement I and Statement II are true
3. C.Statement I is false but Statement II is true
4. D.Statement I is true but Statement II is false

Fat soluble vitamins are: A. Vitamin ${\mathrm{B}}_1$ B. Vitamin C C. Vitamin E D. Vitamin B 12 E. Vitamin K Choose the correct answer from the options given below:

1. A.B & C Only
2. B.C & D Only
3. C.C & E Only
4. D.A & B Only

A tetrapeptide, " $x$ " on complete hydrolysis produced glycine (Gly), alanine (Ala), valine (Val), leucine (Leu) in equimolar proportion each. The number of tetrapeptides (sequences) possible involving each of these amino acids is :

1. A.32
2. B.24
3. C.8
4. D.16

Identify the essential amino acids from below: (A) Valine (B) Proline (C) Lysine (D) Threonine (E) Tyrosine Choose the correct answer from the options given below:

1. A.(A), (C) and (D) only
2. B.(C), (D) and (E) only
3. C.(A), (C) and (E) only
4. D.(B), (C) and (E) only

Given below are two statements: Statement I : D-glucose pentaacetate reacts with 2,4 -dinitrophenylhydrazine Statement II : Starch, on heating with concentrated sulfuric acid at $100^{\circ }\mathrm{C}$ and $2-3\mathrm{atmosphere}$ pressure produces glucose. In the light of the above statements, choose the correct answer from the options given below

1. A.Statement I is true but Statement II is false
2. B.Both Statement I and Statement II are true
3. C.Statement I is false but Statement II is true
4. D.Both Statement I and Statement II are false