GATE Overflow for GATE BT - Recent activity in Analytical Techniques

Edited: GATE BT 2026 | Question: 47

Tue, 17 Mar 2026 07:30:15 +0000

The electron equivalent per liter (e-eq $\mathrm{L}^{-1}$ ) of acetate ion solution of concentration $10 \mathrm{~g} \mathrm{~L}^{-1}$ is $\_\_\_\_$ $\mathrm{e}^{-} \mathrm{eq} \mathrm{L}^{-1}$. (rounded off to one decimal place)

Edited: GATE BT 2026 | Question: 25

Tue, 17 Mar 2026 07:02:38 +0000

You have purified an enzyme using a series of chromatographic methods. It was observed that a $10 ~\mu \mathrm{g} \mathrm{~mL}^{-1}$ of this purified enzyme converted $10$ mM substrate per hour at $25^{\circ} \mathrm{C}$ and pH $7$. Its specific activity is $\_\_\_\_$ $\mathrm{IU} \mu_{\mathrm{g}}{ }^{-1}$. (rounded off to three decimal places)

Edited: GATE BT 2026 | Question: 9

Tue, 17 Mar 2026 06:45:35 +0000

Which one of the following proteins would elute third in gel filtration chromatography from a mixture of four proteins given below?

Insulin $(6 \text{ kDa})$
Myoglobin $(17 \text{ kDa})$
Thrombin $(37 \text{ kDa})$
Albumin $(66 \text{ kDa})$

Edited: GATE BT 2026 | Question: 4

Tue, 17 Mar 2026 06:42:15 +0000

Cancer cells display a high level of heterogeneity in the expression of TP$53$ protein. Which of the following techniques can be directly used to determine the intratumoral heterogeneity of TP$53$ expression in a given tumor sample, without resorting to additional cell separation techniques?

Immunoblotting
Flow cytometry
ELISA
Quantitative RT-PCR

Edited: GATE BT 2025 | Question: 54

Mon, 02 Jun 2025 14:31:44 +0000

An NMR spectrometer operating at proton resonance frequency $(v)$ of $1 \: \mathrm{GHz}$ will have a magnetic field strength of $\_\_\_\_$ Tesla (T).

The gyromagnetic ratio for proton, $\gamma=2.675 \times 10^{8} \mathrm{~T}^{-1} \mathrm{~s}^{-1}$
(Round off to one decimal place)

Edited: GATE BT 2025 | Question: 50

Mon, 02 Jun 2025 14:29:21 +0000

The percentage of light that would pass through a sample with an absorbance of $2$ would be $\_\_\_\_\_$ $\%$ .

(Round off to the nearest integer)

Edited: GATE BT 2025 | Question: 22

Mon, 02 Jun 2025 13:14:26 +0000

Within the Michaelis-Menten framework, the ratio of $v_{0} / V_{\max }$ when $[\mathrm{S}]=20 \times K_{\mathrm{m}}$ is $\_\_\_\_\_$

(Round off to two decimal places)

Edited: GATE BT 2025 | Question: 13

Sun, 01 Jun 2025 19:07:19 +0000

Which of the following separation processes is/are based on molecular size?

Size-exclusion chromatography
Ion exchange chromatography
Membrane ultrafiltration
Ultracentrifugation

Edited: GATE BT 2025 | Question: 55

Sun, 01 Jun 2025 18:56:03 +0000

For the coupled reactions given below
\[
\begin{array}{ll}
\text { Glucose 6-phosphate }+\mathrm{H}_{2} \mathrm{O} \rightarrow \text { Glucose }+\mathrm{Pi} & \text { (Reaction 1) } \\
\text { ATP }+ \text { Glucose } \rightarrow \mathrm{ADP}+\text { Glucose 6-phosphate } & \text { (Reaction 2) }
\end{array}
\]
the standard free energy change of ATP hydrolysis at $25^{\circ} \mathrm{C}$ is $\qquad$ $\mathrm{kJ} / \mathrm{mol}$.

The equilibrium constants for Reaction 1 and Reaction 2 are 360 and 800, respectively; Gas constant $R=8.314 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}$.
(Round off to two decimal places)

Recategorized: GATE BT 2024 | Question: 1

Mon, 21 Apr 2025 15:50:35 +0000

In adsorption chromatography, the adsorption of uncharged solute molecules onto a silica-based stationary phase is by $\_\_\_\_\_\_\_$.

covalent bonds
electrostatic interactions
ionic bonds
van der Waals forces

Recategorized: GATE BT 2024 | Question: 31

Mon, 21 Apr 2025 15:49:25 +0000

Match the item in Column I with the corresponding technique in Column II.

\begin{array}{|c|c|c|}
\hline & \text{Column I} & \text{Column II} \\
\hline & \text{P. Blue laser} & 1. \text{Electron microscopy} \\
\hline & \text{Q. Tungsten filament} & 2. \text{Fluorescence activated cell sorting} \\
\hline & \text{R}. { }^{15} \mathrm{~N labelled protein} & 3. \text{Electrophoresis} \\
\hline & \text{S. Polyacrylamide} & 4. \text{Nuclear magnetic resonance spectroscopy} \\
\hline
\end{array}

$\text{P-2; Q-3; R-1; S-4}$
$\text{P-2; Q-1; R-4; S-3}$
$\text{P-3; Q-1; R-4; S-2}$
$\text{P-3; Q-1; R-4; S-2}$

Recategorized: GATE BT 2024 | Question: 34

Mon, 21 Apr 2025 15:48:58 +0000

Which of the following statements is/are correct about an uncompetitive inhibitor of an enzyme?

It binds to the substrate binding site of the enzyme only
It binds to the enzyme-substrate complex only
It reduces the $\mathrm{V}_{\max }$ of the enzyme
It binds to both free enzyme and enzyme-substrate complex

Recategorized: GATE BT 2023 | Question: 12

Mon, 21 Apr 2025 15:46:09 +0000

In ELISA, which of the following enzymes are conjugated to antibodies for detection of the analyte?

P. Alkaline phosphatase
Q. Trypsinase
R. Horseradish peroxidase
S. Amylase

$\mathrm{P}$ and $\mathrm{R}$
$\text{P}$ and $\text{Q}$
$\text{Q}$ and $\text{S}$
$\mathrm{R}$ and $\mathrm{S}$

Recategorized: GATE BT 2023 | Question: 18

Mon, 21 Apr 2025 15:45:55 +0000

Which one of the following methods CANNOT be used to determine the secondary structure content of a protein?

Circular dichroism spectroscopy
Fourier transform infrared spectroscopy
Mass spectrometry
X-ray crystallography

Recategorized: GATE BT 2023 | Question: 25

Mon, 21 Apr 2025 15:45:24 +0000

The distance between the two points of intersection of $x^{2}+y=7$ and $x+y=7$ (rounded off to two decimal places) is ___________.

Recategorized: GATE BT 2023 | Question: 37

Mon, 21 Apr 2025 15:44:44 +0000

Temperature of a reaction with an activation energy value of $15 \mathrm{kcal} \mathrm{mol}^{-1}$ is increased from $300 \mathrm{~K}$ to $310 \mathrm{~K}$. If the value of the ideal gas constant $(\mathrm{R})$ is $1.9872 \mathrm{cal} . \mathrm{mol}^{-1} \cdot \mathrm{K}^{-1}$, the ratio of the reaction rate constants $\left(k_{310} / k_{300}\right)$(rounded off to two decimal places) is _____________.

Recategorized: GATE BT 2023 | Question: 40

Mon, 21 Apr 2025 15:44:35 +0000

E. coli cultivated at $298 \mathrm{~K}$ uptakes an uncharged compound (A) by passive diffusion. The intracellular and extracellular concentrations of $\mathrm{A}$ are $0.001 \mathrm{M}$ and $0.1 \mathrm{M}$, respectively. If the value of the ideal gas constant $\mathrm{R}$ is $1.9872 \text { cal.mol }^{-1}$. $\mathrm{K}^{-1}$, the free-energy change (in $\mathrm{kcal.mol}^{-1}$) for this passive diffusion of $\mathrm{A}$ (rounded off to two decimal places) is ______________.

Recategorized: GATE BT 2023 | Question: 46

Mon, 21 Apr 2025 15:44:18 +0000

If $1000 \mathrm{bp}$ of a double-helical DNA weighs $1 \times 10^{-18} \mathrm{gm}$ and distance between two $\mathrm{bp}$ is $0.34 \mathrm{~nm}$, the total amount of DNA (in mg, rounded off to one decimal place) required to stretch from Earth to Moon (assuming the distance between Earth and Moon to be $3,74,000 \mathrm{~km}$ ) is ______________.

Recategorized: GATE BT 2023 | Question: 47

Mon, 21 Apr 2025 15:44:15 +0000

A protein has three identical sites arranged at the vertices of an equilateral triangle. If one site is filled with a dye (donor), the measured quantum yield $\left(\phi_{D}\right)$ is $0.5$. Filling one site with a donor dye and a second site with an acceptor dye results in $\phi_{D}$ of $0.25$. The measured $\phi_{D}$ of one site filled with donor and the other two sites filled with acceptor dye (rounded off to three decimal places) is _____________.

Recategorized: GATE BT 2023 | Question: 55

Mon, 21 Apr 2025 15:43:52 +0000

A dNTP master-mix is prepared by combining $40 \mu L$ of each $20 \mathrm{mM}$ dNTP stock (dATP, dCTP, dGTP and dTTP). $4 \mu L$ of this dNTP master-mix is added to a PCR mix and the final volume is adjusted to $50 \mu L$. The concentration (in $\mu M$ ) of total dNTPs in the $\text{PCR}$ mix is _____________.

Recategorized: GATE BT 2022 | Question: 5

Mon, 21 Apr 2025 15:43:36 +0000

The binding free energy of a ligand to its receptor protein is $-11.5 \; \text{kJ mol}^{-1}$ at $300 \; \text{K.}$ What is the value of the equilibrium binding constant?

Use $\text{R = 8.314 J mol}^{-1} \text{K}^{-1}.$

$0.01$
$1.0$
$4.6$
$100.5$

Recategorized: GATE BT 2022 | Question: 30

Mon, 21 Apr 2025 15:42:44 +0000

Match the stationary phase (Column I) with its corresponding chromatography technique (Column II).

$$\begin{array} {lll} \textbf{Column I} & & \textbf{Column II} \\ \text{P. Protein A} & & \text{1. Size exclusion chromatography} \\ \text{Q. Sephadex} & & \text{2. IOn-exchnage chromatography} \\ \text{R. Phenylsepharose} & & \text{3. Affinity chromatography} \\ \text{S. Diethylaminoethyl cellulose} & & \text{4. Hydrophobic interaction chromatography} \end{array}$$

$\text{P-1, Q-4, R-2, S-3}$
$\text{P-3, Q-1, R-4, S-2}$
$\text{P-3, Q-4, R-2, S-1}$
$\text{P-4, Q-1, R-3, S-2}$

Recategorized: GATE BT 2022 | Question: 35

Mon, 21 Apr 2025 15:42:01 +0000

Which of the following spectroscopic technique(s) can be used to identify all the functional groups of an antibiotic contaminant in food?

Infrared
Circular dichroism
Nuclear magnetic resonance
UV-Visible

$\text{P}$ only
$\text{P}$ and $\text{R}$ only
$\text{P, Q}$ and $\text{R}$ only
$\text{P, Q, R}$ and $\text{S}$

Recategorized: GATE BT 2021 | Question: 38

Mon, 21 Apr 2025 15:39:29 +0000

Which of the following nucleus/nuclei is/are $\text{NMR}$ active?

$^1H$
$^{13}C$
$^{16}O$
$^{32}S$

Recategorized: GATE BT 2021 | Question: 53

Mon, 21 Apr 2025 15:38:56 +0000

A $\text{DNA}$ solution of $50 \: \mu g \: mL^{-1}$ concentration gives an absorbance of $1.0$ at $260 \textit{ nm}$. An aliquot of $20 \: \mu L$ from a $50 \: \mu L$ purified plasmid solution is diluted with distilled water to a total volume of $1000 \: \mu L$. The diluted plasmid solution gives an absorbance of $0.550$ at $260 \textit{ nm}$. The concentration of the purified plasmid in $\mu g \: \mu L^{-1}$ (rounded off to two decimal places) is ________.

Recategorized: GATE2020: 21

Mon, 21 Apr 2025 15:38:29 +0000

The number of molecules of a nucleotide of molecular weight $300\:g$/mol present in $10$ picomoles is ____________ $\times10^{12}$ (round off to $2$ decimal places).

Recategorized: GATE2020: 53

Mon, 21 Apr 2025 15:37:33 +0000

The concentrations of $ATP$, $ADP$ and inorganic phosphate in a cell are $2.59, \:0.73$ and $2.72 \:mM$, respectively. Under these conditions, free energy change for the synthesis of $ATP$ at $37^{\circ}C$ is $kJ$/mol (round off to $2$ decimal places).

Given: free energy change for $ATP$ hydrolysis under standard conditions is $-30.5$ $kJ$/mol and $R=8.315$ $kJ/mol.K$

Recategorized: GATE2020: 8

Mon, 21 Apr 2025 15:36:32 +0000

Two monomeric His-tagged proteins of identical molecular weight are present in a solution. pIs of these two proteins are $5.6$ and $6.8$. Which one of the following techniques can be used to separate them?

Denaturing polyacrylamide gel electrophoresis
Size-exclusion chromatography
Ion-exchange chromatography
Nickel affinity chromatography

Recategorized: GATE2020: 20

Mon, 21 Apr 2025 15:36:26 +0000

Solvents $A$ and $B$ are completely immiscible. Solute $S$ is soluble in both these solvents. $100\: g$ of $S$ was added to a container which has $2\: kg$ each of $A$ and $B$. The solute is $1.5$ times more soluble in solvent $A$ than in solvent $B$. The mixture was agitated thoroughly and allowed to reach equilibrium. Assuming that the solute has completely dissolved, the amount of solute in solvent $A$ phase is _____________ $g$.

Recategorized: GATE2019: 25

Mon, 21 Apr 2025 15:36:15 +0000

Protein concentration of a crude enzyme preparation was $10\:mg\:mL^{-1}$. $10\:\mu L$ of this sample gave an activity of $5\:\mu mol\:min^{-1}$ under standard assay conditions. The specific activity of this crude enzyme preparation is ____________ units $mg^{-1}$.

Recategorized: GATE2019: 33

Mon, 21 Apr 2025 15:36:03 +0000

The hexapeptide $P$ has an isoelectric point $(pI)$ of $6.9$. Hexapeptide $Q$ is a variant of $P$ that contains valine instead of glutamate at position $3$. The two peptides are analyzed by polyacrylamide gel electrophoresis at pH $8.0$. Which one of the following statements is CORRECT?

$P$ will migrate faster than $Q$ towards the anode
$P$ will migrate faster than $Q$ towards the cathode
Both $P$ and $Q$ will migrate together
$Q$ will migrate faster than $P$ towards the anode

Recategorized: GATE2019: 32

Mon, 21 Apr 2025 15:35:54 +0000

$Group\; I$ lists spectroscopic methods and $Group\; II$ lists biomolecular applications of these methods. Match the methods in $Group\; I$ with the applications in $Group\; II$.

$$\begin{array}&&\textbf{Group I} & \textbf{Group II} \\ &\text{P. Infrared} & \text{1. Identification of functional groups}\\
&\text{Q. Circular Dichroism} & \text{2. Determonation of secondary structure} \\
&\text{R. Nuclear Magnetic Resonance} & \text{3. Estimation of molecular weight} \\
&\text{} & \text{4. Determination of $3-D$ structure} \\ \end{array}$$

$P-4, Q-3, R-1$
$P-2, Q-1, R-3$
$P-1, Q-2, R-4$
$P-3, Q-2, R-4$

Recategorized: GATE2019: 46

Mon, 21 Apr 2025 15:35:15 +0000

The difference in concentrations of an uncharged solute between two compartments is $1.6$-fold. The energy required for active transport of the solute across the membrane separating the two compartments is _________ $cal\:mol^{-1}$ (rounded off to the nearest integer). $(R =1.987\:cal\:mol^{-1}\:K^{-1},\:T=37 \;^{\circ}C)$

Recategorized: GATE2019: 45

Mon, 21 Apr 2025 15:35:12 +0000

A UV-visible spectrophotometer has a minimum detectable absorbance of $0.02$. The minimum concentration of a protein sample that can be measured reliably in this instrument with a cuvette of $1cm$ path length is _________$\mu M$ . The molar extinction coefficient of the protein is $10,000\;L\:mol^{-1}\:cm^{-1}$.

Recategorized: GATE BT 2017 | Question: 5

Mon, 21 Apr 2025 15:33:15 +0000

In a thin layer chromatography experiment using a silica gel plate, a compound showed migration of $12.5$ cm and the solvent front showed migration of $18$ cm. The $R_f$ value for the compound is ______

Recategorized: GATE BT 2017 | Question: 9

Mon, 21 Apr 2025 15:32:51 +0000

Which one of the following techniques can be used to determine the structure of a $15$ kDa globular protein at atomic resolution?

Raman spectroscopy
IR spectroscopy
UV spectroscopy
NMR spectroscopy

Recategorized: GATE BT 2017 | Question: 26

Mon, 21 Apr 2025 15:32:15 +0000

Which one of the following graphs represents the kinetics of protein precipitation by addition of ammonium sulphate? On the $Y$-axis, [Protein] represents the concentration of free protein in solution

Recategorized: GATE BT 2017 | Question: 34

Mon, 21 Apr 2025 15:31:57 +0000

The concentration (in micromolar) of NADH in a solution with $A_{340}=0.50$ is _________

Given data: Path length $=1$ cm; Molar extinction coefficient of NADH $\varepsilon_{340}= 6220 M^{-1}cm^{-1}$

Recategorized: GATE BT 2017 | Question: 30

Mon, 21 Apr 2025 15:31:48 +0000

The circular dichroism spectra of three proteins $P$, $Q$, and $R$ are given below:

Choose the correct combination.

$P: \alpha- \text{helix}, Q: \beta- \text{sheet}, \text{ and } R: \text{Random coil}$
$P: \beta- \text{sheet}, Q: \alpha- \text{helix}, \text{ and }R: \text{Random coil}$
$P: \beta- \text{helix}, Q: \alpha- \text{Random coil}, \text{ and }R: \text{sheet}$
$P: \beta- \text{Random coil}, Q: \alpha- \text{helix}, \text{ and }R: \text{sheet}$

Recategorized: GATE BT 2017 | Question: 35

Mon, 21 Apr 2025 15:31:26 +0000

The specific activity of an enzyme in a crude extract of $\textit{E.coli}$ is $9.5$ units/mg of protein. The specific activity increased to $68$ units/mg of protein upon ion-exchange chromatography. The fold purification is ________

Recategorized: GATE BT 2017 | Question: 50

Mon, 21 Apr 2025 15:30:50 +0000

The interaction energy $E$ between two spherical particles is plotted as a function of the distance $(r)$ between them. When $r<a$, where $a$ is a constant, the net force between the spherical particles is repulsive. When $r \geq a$, they attract via van der Waals attraction. Which one of the following plots correctly represents the interaction energy between the above two particles>

Recategorized: GATE2016-13

Mon, 21 Apr 2025 15:29:57 +0000

Which one of the following techniques relies on the spin angular momentum of a photon?

CD spectroscopy
Fluorescence spectroscopy
IR spectroscopy
Raman spectroscopy

Recategorized: GATE2016-35

Mon, 21 Apr 2025 15:29:17 +0000

The equilibrium potential of a biological membrane for $Na^+$ is $55$ mV at $37^\circ$ C. Concentration of $Na^+$ inside the cell is $20$ mM. Assuming the membrane is permeable to $Na^+$ only, the $Na^+$ concentration outside the membrane will be __________mM.

(Faraday constant: $23062 \text{ cal} \cdot V^{-1}\cdot \text{mol}^{-1}$, Gas constant: $1.98 \text{ cal.mol}^{-1}.K^{-1}$)

Recategorized: GATE2016-43

Mon, 21 Apr 2025 15:29:02 +0000

The molar extinction coeffcients of Trp and Tyr at $280$ nm are $5690$ and $1280 \: M^{-1} \cdot cm^{-1}$, respectively. The polypeptide chain of yeast alcohol dehydrogenase ($37$ kDa) contains $5$ Trp and $14$ Tyr residues. The absorbance at $280$ nm of a $0.32 \text{ mg . mL}^{-1}$ solution of yeast alcohol dehydrogenase measured in a cuvette of $1$ cm pathlength will be _________

(Assume that the molar extinction coefficient values for Trp and Tyr apply to these amino acids inthe yeast alcohol dehydrogenase).

Recategorized: GATE2016-42

Mon, 21 Apr 2025 15:28:59 +0000

In an assay of the type II dehydroquinase of molecular mass $18$ kDa, it is found that the $V_{\text{max}}$ of the enzyme is $0.0134 \: \mu \text{ mol} \cdot \text{min}^{-1}$ when $1.8 \: \mu g$ enzyme is added to the assay mixture. If the $K_m$ for the substrate is $25 \: \mu M$, the $k_{\text{cat}}/K_m$ ratio will be _______ $\times 10^4 \: M^{-1} \cdot s^{-1}$

Recategorized: GATE2016-44

Mon, 21 Apr 2025 15:28:27 +0000

The activity of lactate dehydrogenase can be measured by monitoring the following reaction: $$\text{Pyruvate} + \text{NADH} \rightarrow \text{Lactate} + \text{NAD}^+$$ The molar extinction coefficient of NADH at $340$ nm is $6220 \: M^{-1} \cdot cm^{-1}. NAD^+$ does not absorb at this wavelength. In an assay, $25$ $\mu L$ of a sample of enzyme (containing $5 \: \mu g$ protein per mL) was added to a mixture of pyruvate and NADH to give a total volume of $3$ mL in a cuvette of $1$ cm pathlength. The rate of decrease in absorbance at $340$ nm was $0.14 \: \text{min}^{-1}$. The specific activity of the enzyme will be __________ $\mu \text{mol.min}^{-1}.mg^{-1}$

Recategorized: GATE2016-55

Mon, 21 Apr 2025 15:28:22 +0000

Consider the equation

$V=\dfrac{aS}{b+S+\dfrac{S^2}{c}}$

Given $a = 4$, $b = 1$ and $c = 9$, the positive value of $S$ at which $V$ is maximum, will be _________

Recategorized: GATE2016-51

Mon, 21 Apr 2025 15:28:16 +0000

A protein is to be purified using ion-exchange column chromatography. The relationship between HETP (Height Equivalent to Theoretical Plate) and the linear liquid velocity of mobile phase is given by:

$H = \dfrac{A}{u} + Bu + C$

Where $H$ is HETP (m) and $u$ is linear liquid velocity of mobile phase $(ms^{-1})$. The values of $A, B$ and $C$ are $3 \times 10^8 \: m^2 \cdot s^{-1}$, $3 \: s$ and $6 \times 10^{-5} m$, respectively. The number of theoretical plates based on minimum HETP for a column of $66$ cm length will be _________

Recategorized: GATE BT 2015 | Question: 19

Mon, 21 Apr 2025 15:27:42 +0000

A single subunit enzyme converts $420$ $\mu$moles of substrate to product in one minute. The activity of the enzyme is ________ $\times 10^{-6}$ Kalal.

Recategorized: GATE BT 2015 | Question: 31

Mon, 21 Apr 2025 15:27:22 +0000

Which one of the following graphs represents uncompetitive inhibition?