IISER IAT 2026 question paper

1. A.
   i, ii and iii
2. B.
   ii, iii and iv
3. C.
   i, ii and iv
4. D.
   i, iii and iv

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1. A.
   P - (iii); Q - (iv); R - (i); S - (ii)
2. B.
   P - (ii); Q - (i); R - (iv); S - (iii)
3. C.
   P - (iv); Q - (iii); R - (ii); S - (i)
4. D.
   P - (i); Q - (ii); R - (iii); S - (iv)

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1. A.
   Q is a predator of P
2. B.
   Q is a commensal of P
3. C.
   P and Q exhibit mutualism
4. D.
   P is a parasite of Q

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1. A.
   The cells with the recombinant plasmid can grow in the presence of both ampicillin and tetracycline
2. B.
   The cells with the non-recombinant plasmid can grow in the presence of ampicillin but not tetracycline
3. C.
   The cells with the non-recombinant plasmid can grow in the presence of tetracycline but not ampicillin
4. D.
   The cells with the recombinant plasmid can grow in the presence of ampicillin but not tetracycline

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1. A.
   Plot of velocity of reaction (V) against [S] with a dashed Vmax line at V = 16: V is 1 at [S] = 5, about 2 at [S] = 10, about 4 at [S] = 20, 9 at [S] = 40, 12 at [S] = 60, 15 at [S] = 80, and 16 at [S] = 100 and 150
2. B.
   Plot of velocity of reaction (V) against [S] with a dashed Vmax line at V = 16: V is 1 at [S] = 5, 2 at [S] = 10, 4 at [S] = 20, 8 at [S] = 40, 12 at [S] = 60, 15 at [S] = 80, and 16 at [S] = 100 and 150
3. C.
   Plot of velocity of reaction (V) against [S] with a dashed Vmax line at V = 16: V is 2.5 at [S] = 5, 5 at [S] = 10, 8 at [S] = 20, 12 at [S] = 40, about 15.5 at [S] = 60, and 16 from [S] = 80 to 150
4. D.
   Plot of velocity of reaction (V) against [S] with a dashed Vmax line at V = 16: V is 8 at [S] = 5, 12 at [S] = 10, 16 at [S] = 20, slightly above 16 at [S] = 40 and 60, and 16 at [S] = 80 to 150

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1. A.
   Both FSH and estrogen regulate gene expression via intracellular receptors
2. B.
   Both FSH and estrogen regulate cellular metabolism via membrane-bound receptors
3. C.
   FSH interacts with membrane-bound receptor and generates cyclic AMP, while estrogen interacts with intracellular receptor and regulates gene expression
4. D.
   FSH interacts with intracellular receptor and generates cyclic AMP, while estrogen interacts with membrane-bound receptor and regulates cellular metabolism

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1. A.
   Protists
2. B.
   Fungi
3. C.
   Plants
4. D.
   Animals

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1. A.
   5'-CACGACATTGCCGAAGTG-3'
2. B.
   5'-GTGAAGCCGTTACAGCAC-3'
3. C.
   5'-GTGCTGTAACGGCTTCAC-3'
4. D.
   5'-CACTTCGGCAATGTCGTG-3'

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1. A.
   Decrease of $\mathrm{Ca^{++}}$ in sarcoplasm, masking of active sites for myosin, 'Z' lines pulled inwards
2. B.
   Increase of $\mathrm{Ca^{++}}$ in sarcoplasm, unmasking of active sites for myosin, 'Z' lines pulled outwards
3. C.
   Increase of $\mathrm{Ca^{++}}$ in sarcoplasm, unmasking of active sites for myosin, 'Z' lines pulled inwards
4. D.
   Increase of $\mathrm{Ca^{++}}$ in sarcoplasm, masking of active sites for myosin, 'Z' lines pulled inwards

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1. A.
   Anti-Rh antibody to the Rh-negative mother after delivery of the first Rh-positive child
2. B.
   Anti-Rh antibody to the Rh-positive mother after delivery of the first Rh-negative child
3. C.
   Anti-Rh antibody to the Rh-negative mother after delivery of the first Rh-negative child
4. D.
   Anti-Rh antibody to the Rh-positive mother after delivery of the first Rh-positive child

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1. A.
   iii and iv
2. B.
   i and iii
3. C.
   i and ii
4. D.
   ii and iv

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1. A.
   Father: AB; Mother: A
2. B.
   Father: AB; Mother: O
3. C.
   Father: A; Mother: O
4. D.
   Father: O; Mother: B

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1. A.
   ACGGAACCATGCAGAGAGG
2. B.
   ACGGAACCAUGCAGAGAGG
3. C.
   ACGGAACCAUGCAGAGAGG paired with UGCCUUGGUACGUCUCUCC
4. D.
   ACGGAACCATGCAGAGAGG paired with TGCCTTGGTACGTCTCTCC

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1. A.
   Y-linked
2. B.
   X-linked recessive
3. C.
   Mitochondrial
4. D.
   X-linked dominant

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1. A.
   Anaphase I
2. B.
   Prophase I
3. C.
   Metaphase I
4. D.
   Telophase I

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1. A.
   $\mathrm{[Cr(H_2O)_4(OH)_2]}$
2. B.
   $\mathrm{[V(H_2O)_4I_2]^+}$
3. C.
   $\mathrm{[Co(NH_3)_4Cl_2]}$
4. D.
   $\mathrm{[Fe(NH_3)_4(CN)_2]^+}$

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1. A.
   14, 6
2. B.
   7, 3
3. C.
   6, 14
4. D.
   7, 6

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1. A.
   $\mathrm{F_2}$
2. B.
   $\mathrm{B_2}$
3. C.
   $\mathrm{N_2}$
4. D.
   $\mathrm{C_2}$

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1. A.
   $\mathrm{Mn_2(CO)_{10}}$: metal orbital $\rightarrow$ ligand orbital; $\mathrm{[MnO_4]^-}$: ligand orbital $\rightarrow$ metal orbital
2. B.
   $\mathrm{Mn_2(CO)_{10}}$: ligand orbital $\rightarrow$ metal orbital; $\mathrm{[MnO_4]^-}$: ligand orbital $\rightarrow$ metal orbital
3. C.
   $\mathrm{Mn_2(CO)_{10}}$: ligand orbital $\rightarrow$ metal orbital; $\mathrm{[MnO_4]^-}$: metal orbital $\rightarrow$ ligand orbital
4. D.
   $\mathrm{Mn_2(CO)_{10}}$: metal orbital $\rightarrow$ ligand orbital; $\mathrm{[MnO_4]^-}$: metal orbital $\rightarrow$ ligand orbital

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1. A.
   $\mathrm{C{=}S > C{=}Te}$ and $\mathrm{Cl{-}Cl > F{-}F}$
2. B.
   $\mathrm{C{=}Te > C{=}S}$ and $\mathrm{F{-}F > Cl{-}Cl}$
3. C.
   $\mathrm{C{=}S > C{=}Te}$ and $\mathrm{F{-}F > Cl{-}Cl}$
4. D.
   $\mathrm{C{=}Te > C{=}S}$ and $\mathrm{Cl{-}Cl > F{-}F}$

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1. A.
   The reaction rate does not change upon increasing the concentration of hydroxide ion.
2. B.
   The reaction rate decreases upon changing the solvent from ethyl alcohol to 1:1 mixture of ethyl alcohol and water.
3. C.
   The reaction rate is proportional to the concentration of tert-butylbromide.
4. D.
   The rate determining step is the dissociation of tert-butylbromide.

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1. A.
   2,4,5,6-tetramethyl-1,3-dioxane drawn with the 2-methyl on a wedge (2-H hashed), the 4-methyl hashed, the 5-methyl on a wedge (5-H hashed) and the 6-methyl hashed
2. B.
   2,4,5,6-tetramethyl-1,3-dioxane drawn with the 2-methyl on a wedge (2-H hashed), the 4-methyl on a wedge, the 5-methyl hashed (5-H on a wedge) and the 6-methyl hashed
3. C.
   2,4,5,6-tetramethyl-1,3-dioxane drawn with the 2-methyl on a wedge (2-H hashed), the 4-methyl hashed, the 5-methyl hashed (5-H on a wedge) and the 6-methyl hashed
4. D.
   2,4,5,6-tetramethyl-1,3-dioxane drawn with the 2-methyl on a wedge (2-H hashed), the 4-methyl on a wedge, the 5-methyl on a wedge (5-H hashed) and the 6-methyl on a wedge

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1. A.
   B is more polar than A; A has $\mathrm{R}_f = 0.75$.
2. B.
   B is less polar than A; B has $\mathrm{R}_f = 0.75$.
3. C.
   B is more polar than A; A has $\mathrm{R}_f = 0.25$.
4. D.
   A is more polar than B; B has $\mathrm{R}_f = 0.33$.

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1. A.
   X = $\mathrm{\mathit{o}\text{-}C_6H_4(COOD)(CH_2ONa)}$; P = 2-benzofuran-1(3H)-one (phthalide)
2. B.
   X = $\mathrm{\mathit{o}\text{-}C_6H_4(COONa)(CHDOH)}$; P = 3-deuterio-1,3-dihydro-2-benzofuran-1-ol
3. C.
   X = $\mathrm{\mathit{o}\text{-}C_6H_4(COOH)(CHDONa)}$; P = 3-deuterio-1,3-dihydro-2-benzofuran-1-ol
4. D.
   X = $\mathrm{\mathit{o}\text{-}C_6H_4(COONa)(CHDOH)}$; P = 3-deuterio-2-benzofuran-1(3H)-one (3-deuteriophthalide)

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1. A.
   S < P < Q < R
2. B.
   P < R < Q < S
3. C.
   P < Q < R < S
4. D.
   S < P < R < Q

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1. A.
   0.10 M
2. B.
   0.33 M
3. C.
   0.50 M
4. D.
   0.17 M

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1. A.
   (i), (ii), and (iii) only
2. B.
   (i) and (iii) only
3. C.
   (i) only
4. D.
   (ii) and (iv) only

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1. A.
   1:1
2. B.
   1:2
3. C.
   6:1
4. D.
   3:2

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1. A.
   $p_{\text{total}} > (p^0_{\mathbf{X}} + p^0_{\mathbf{Y}})/2$
2. B.
   $p_{\text{total}} < (p^0_{\mathbf{X}} + p^0_{\mathbf{Y}})/2$
3. C.
   $p_{\text{total}} = p^0_{\mathbf{X}} + p^0_{\mathbf{Y}}$
4. D.
   $p_{\text{total}} = (p^0_{\mathbf{X}} + p^0_{\mathbf{Y}})/2$

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1. A.
   680 K
2. B.
   720 K
3. C.
   640 K
4. D.
   760 K

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1. A.
   $0$
2. B.
   $-1$
3. C.
   $2$
4. D.
   $1$

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1. A.
   $A$ is finite but $B$ is infinite.
2. B.
   $A$ is infinite but $B$ is finite.
3. C.
   $A$ is finite and $B$ is also finite.
4. D.
   $A$ is infinite and $B$ is also infinite.

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1. A.
   $\overrightarrow{AB}$, $\overrightarrow{BC}$ and $\overrightarrow{CA}$ are mutually perpendicular.
2. B.
   $\overrightarrow{AB} \times \overrightarrow{BC} = \hat{i} + \hat{j} + \hat{k}$.
3. C.
   $\overrightarrow{AB} + 3\overrightarrow{BC}$ is perpendicular to $\overrightarrow{AC}$.
4. D.
   $A$, $B$ and $C$ are collinear.

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1. A.
   $30^\circ$
2. B.
   $45^\circ$
3. C.
   $90^\circ$
4. D.
   $60^\circ$

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1. A.
   $r^{r-l}(r-1)(r-2)\cdots(r-l+1)$
2. B.
   $r^{r-l+1}(r-1)(r-2)\cdots(r-l+1)$
3. C.
   $r^r$
4. D.
   $r(r-1)(r-2)\cdots(r-l+1)$

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1. A.
   $\mathcal{R}$ is reflexive and symmetric but not transitive.
2. B.
   $\mathcal{R}$ is not a relation.
3. C.
   $\mathcal{R}$ is symmetric and transitive but not reflexive.
4. D.
   $\mathcal{R}$ is reflexive and transitive but not symmetric.

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1. A.
   $2$
2. B.
   $1$
3. C.
   $-1$
4. D.
   $0$

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1. A.
   The mean deviation about the mean does not change.
2. B.
   The mean deviation about the median is increased by 2.
3. C.
   The mean deviation about the mean is increased by 2.
4. D.
   The variance is increased by 2.

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1. A.
   $f(x) > 0$, for all $x \in \left(0, \frac{\pi}{48}\right)$.
2. B.
   $f\left(\frac{\pi}{12}\right) = 0$
3. C.
   $f\left(x + \frac{\pi}{2}\right) + f(x) = 0$, for all $x \in \mathbb{R}$.
4. D.
   $f$ is increasing on $\left(\frac{3\pi}{2}, 2\pi\right)$.

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1. A.
   $0$
2. B.
   infinitely many
3. C.
   $1$
4. D.
   $2$

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1. A.
   $A_m - A_{m-1} - \begin{bmatrix} 1 & 0 \\ 0 & 1 \end{bmatrix} = \begin{bmatrix} 0 & 0 \\ 0 & 0 \end{bmatrix}$
2. B.
   $A_1^m = A_1^{m-1} + A_1^{m-2}$
3. C.
   $A_1^m - A_1^{m-1} + \begin{bmatrix} 1 & 0 \\ 0 & 1 \end{bmatrix} = \begin{bmatrix} 0 & 0 \\ 0 & 0 \end{bmatrix}$
4. D.
   $\det(A_m) = -1$

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1. A.
   $99$
2. B.
   $255$
3. C.
   $93$
4. D.
   $120$

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1. A.
   $2$
2. B.
   $1$
3. C.
   $49$
4. D.
   $90$

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1. A.
   $\frac{33}{53}$
2. B.
   $\frac{99}{257}$
3. C.
   $\frac{3}{7}$
4. D.
   $\frac{35}{57}$

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1. A.
   $0$
2. B.
   $2$
3. C.
   $3$
4. D.
   $1$

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1. A.
   If $\ell$ increases, $T$ decreases.
2. B.
   If $\ell$ increases, $T$ increases.
3. C.
   The sphere never moves.
4. D.
   If $\ell$ increases, $T$ does not change.

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1. A.
   20 cm
2. B.
   25 cm
3. C.
   12 cm
4. D.
   30 cm

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1. A.
   $q$ is positive and $\hat{\mathbf{n}} = -\hat{\mathbf{z}}$
2. B.
   $q$ is positive and $\hat{\mathbf{n}} \cdot \hat{\mathbf{z}} = -\frac{1}{\sqrt{2}}$
3. C.
   $q$ is negative and $\hat{\mathbf{n}} = \hat{\mathbf{z}}$
4. D.
   $q$ is positive and $\hat{\mathbf{n}} = \hat{\mathbf{z}}$

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1. A.
   $\frac{m_1}{m_2}$
2. B.
   $\sqrt{\frac{m_1}{m_2}}$
3. C.
   $\frac{m_2}{m_1}$
4. D.
   $\sqrt{\frac{m_2}{m_1}}$

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1. A.
   $\left[\left(1 + \frac{\rho g d}{B}\right)^{2/3} - 1\right]$
2. B.
   $\left[\left(1 + \frac{\rho g d}{B}\right)^{1/3} - 1\right]$
3. C.
   $\left[1 - \left(1 - \frac{\rho g d}{B}\right)^{2/3}\right]$
4. D.
   $\left[1 - \left(1 - \frac{\rho g d}{B}\right)^{1/3}\right]$

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1. A.
   $\frac{T}{2}$
2. B.
   $T$
3. C.
   $\frac{T}{4}$
4. D.
   $2T$

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1. A.
   $\frac{1}{\sqrt{2}}(4t - 2t^2)$
2. B.
   $4t + 6t^2$
3. C.
   $\frac{1}{\sqrt{2}}(4t + 6t^2)$
4. D.
   $4t - 2t^2$

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1. A.
   $B_{in}$ increases, $U_{in}$ decreases.
2. B.
   $B_{in}$ increases, $U_{in}$ increases.
3. C.
   $B_{in}$ decreases, $U_{in}$ increases.
4. D.
   $B_{in}$ decreases, $U_{in}$ decreases.

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1. A.
   $[\alpha] = [M^0 L^7 T^{-2}]$, $[\beta] = [M^0 L^0 T^{-1}]$
2. B.
   $[\alpha] = [M^1 L^6 T^{-2}]$, $[\beta] = [M^0 L^0 T^{-3}]$
3. C.
   $[\alpha] = [M^0 L^7 T^{-2}]$, $[\beta] = [M^0 L^0 T^0]$
4. D.
   $[\alpha] = [M^0 L^6 T^{-1}]$, $[\beta] = [M^0 L^1 T^{-2}]$

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1. A.
   $1.8\frac{P}{c}$
2. B.
   $0.9\frac{P}{c}$
3. C.
   $1.6\frac{P}{c}$
4. D.
   $1.7\frac{P}{c}$

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1. A.
   $\frac{h}{mc}\left(1 - \sqrt{1 - \frac{2\phi_0}{mc^2}}\right)^{-1}$
2. B.
   $\frac{h}{mc}\left(1 - \sqrt{1 - \frac{\phi_0}{mc^2}}\right)^{-1}$
3. C.
   $\frac{h}{mc}\left(1 + \sqrt{1 - \frac{\phi_0}{mc^2}}\right)^{-1}$
4. D.
   $\frac{h}{mc}\left(1 + \sqrt{1 - \frac{2\phi_0}{mc^2}}\right)^{-1}$

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1. A.
   $8$
2. B.
   $2$
3. C.
   $\frac{1}{2}$
4. D.
   $\frac{1}{8}$

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