Biomolecules · JEE Main previous year questions

If $250\mathrm{c}{\mathrm{m}}^3$ of an aqueous solution containing $0.73\mathrm{g}$ of a protein A is isotonic with one litre of another aqueous solution containing $1.65\mathrm{g}$ of a protein B, at $298\mathrm{K}$, the ratio of the molecular masses of A and B is ____ $\times 10^{-2}$ (to the nearest integer).

An open beaker of water in equilibrium with water vapour is in a sealed container. When a few grams of glucose are added to the beaker of water, the rate at which water molecules :

1. A.leaves the solution increases
2. B.leaves the vapour increases
3. C.leaves the vapour decreases
4. D.leaves the solution decreases

Consider the following reactions: (i) $\text{Glucose}+\mathrm{ROH}\stackrel{\text{dry }\mathrm{HCl}}{\to }\text{Acetal}\stackrel{\text{x eq. of }(\mathrm{C}{\mathrm{H}}_3\mathrm{CO}{)}_2\mathrm{O}}{\to }\text{acetyl derivative}$ (ii) $\text{Glucose}\stackrel{Ni/{\mathrm{H}}_2}{\to }\mathrm{A}\stackrel{\text{y eq. of }(\mathrm{C}{\mathrm{H}}_3\mathrm{CO}{)}_2\mathrm{O}}{\to }\text{acetyl derivative}$ (iii) $\text{Glucose}\stackrel{\text{z eq. of }(\mathrm{C}{\mathrm{H}}_3\mathrm{CO}{)}_2\mathrm{O}}{\to }\text{acetyl derivative}$ 'x', 'y' and 'z' in these reactions are respectively.

1. A.5, 6 & 5
2. B.4, 5 & 5
3. C.4, 6 & 5
4. D.5, 4 & 5

The internal energy change (in J) When $90\mathrm{g}$ of water undergoes complete evaporation at $100^{\circ }\mathrm{C}$ is ____. (Given : $\Delta {\mathrm{H}}_{\mathrm{vap}}$ for water at $373\mathrm{K}=41kJ/mol$, $\mathrm{R}=8.314\mathrm{J}{\mathrm{K}}^{-1}\mathrm{mo}{\mathrm{l}}^{-1}$)

Which of the following statement is not true for glucose?

1. A.Glucose gives Schiff's test for aldehyde
2. B.Glucose reacts with hydroxylamine to form oxime
3. C.The pentaacetate of glucose does not react with hydroxylamine to give oxime
4. D.Glucose exists in two crystalline forms $\alpha$ and $\beta$

Two monomers in maltose are :

1. A.$\alpha$-D-glucose and $\alpha$-D-galactose
2. B.$\alpha$-D-glucose and $\alpha$-D-Fructose
3. C.$\alpha$-D-glucose and $\alpha$-D-glucose
4. D.$\alpha$-D-glucose and $\beta$-D-glucose

Among the reactions (a) - (d), the reaction(s) that does/do not occur in the blast furnace during the extraction of iron is/are : (a) $\mathrm{CaO}+\mathrm{Si}{\mathrm{O}}_2\to \mathrm{CaSi}{\mathrm{O}}_3$ (b) $3F{\mathrm{e}}_2{\mathrm{O}}_3+\mathrm{CO}\to 2F{\mathrm{e}}_3{\mathrm{O}}_4+\mathrm{C}{\mathrm{O}}_2$ (c) $\mathrm{FeO}+\mathrm{Si}{\mathrm{O}}_2\to \mathrm{FeSi}{\mathrm{O}}_3$ (d) $\mathrm{FeO}\to \mathrm{Fe}+\frac{1}{2}{\mathrm{O}}_2$

1. A.(a) and (d)
2. B.(c) and (d)
3. C.(a)
4. D.(d)

At constant volume, 4 mol of an ideal gas when heated from 300 K to 500K changes its internal energy by 5000 J. The molar heat capacity at constant volume is _______.

Glucose and Galactose are having identical configuration in all the positions except position

1. A.C–5
2. B.C–3
3. C.C–2
4. D.C–4

Which of the following statements is not true about RNA?

1. A.It controls the synthesis of protein
2. B.It is present in the nucleus of the cell
3. C.It usually does not replicate
4. D.It has always double stranded $\alpha$-helix structure

An ideal gas is allowed to expand from 1 L to 10 L against a constant external pressure of 1 bar. The work done in kJ is :

1. A.+10.0
2. B.–0.9
3. C.– 2.0
4. D.– 9.0

Which of the given statements is INCORRECT about glycogen?

1. A.It is a straight chain polymer similar to amylose
2. B.It is present in animal cells
3. C.It is present in some yeast and fungi
4. D.Only $\alpha$-linkages are present in the molecule

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

Number of stereo centers present in linear and cyclic structures of glucose are respectively :

1. A.4 & 4
2. B.4 & 5
3. C.5 & 4
4. D.5 & 5

Which of the following statements is not true about sucrose?

1. A.The glycosidic linkage is present between ${\mathrm{C}}_1$ of $\alpha$-glucose and ${\mathrm{C}}_1$ of $\beta$-fructose
2. B.It is also named as invert sugar
3. C.It is a non reducing sugar
4. D.On hydrolysis, it produces glucose and fructose

During compression of a spring the work done is 10kJ and 2kJ escaped to the surroundings as heat. The change in internal energy, $\Delta \mathrm{U}(\mathrm{inkJ})$ is :

1. A.- 12
2. B.8
3. C.- 8
4. D.12

Fructose and glucose can be distinguished by :

1. A.Barfoed's test
2. B.Fehling's test
3. C.Seliwanoff's test
4. D.Benedict's test

Among the following compounds most basic amino acid is -

1. A.Lysine
2. B.Asparagine
3. C.Histidine
4. D.Serine

The correct statement (s) among I to III with respect to potassium ions that are abundant within the cell fluid is /are I. They activate many enzymes II. They participate in the oxidation of glucose to produce ATP III. Along with sodium ions they are responsible for the transmission of nerve signals

1. A.III only
2. B.I and II only
3. C.I and III only
4. D.I, II and III only

The increasing order of pka of the following amino acids in aqueous solution is : Gly, Asp, Lys, Arg

1. A.Asp < Gly < Arg < Lys
2. B.Gly < Asp < Arg < Lys
3. C.Asp < Gly < Lys < Arg
4. D.Arg < Lys < Gly < Asp

Glucose on prolonged heating with HI gives

1. A.6-iodohexanal
2. B.n-Hexane
3. C.1-Hexene
4. D.Hexanoic acid

Among the following, the essential amino acid is :

1. A.Alanine
2. B.Valine
3. C.Aspartic acid
4. D.Serine

$18\mathrm{g}$ glucose (${\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6$) is added to $178.2\mathrm{g}$ water. The vapor pressure of water (in torr) for this aqueous solution is :

1. A.$76.0$
2. B.$752.4$
3. C.$759.0$
4. D.$7.6$

Which of the vitamins given below is water soluble?

1. A.Vitamin D
2. B.Vitamin E
3. C.Vitamin K
4. D.Vitamin C