CBSE EXAMINATION PAPER-2016
NEET-ZOOLOGY
(Solved)
General Instructions :
Read the following instructions carefully and follow them :
- This question paper contains 180 questions. All questions are compulsory.
- This question paper is divided into 1 sections.
- Section A – questions number 1 to 180 are multiple choice questions
- There is no overall choice given in the question paper. However, an internal choice has been provided in few questions.
- Use of calculator is NOT allowed.
Section A
If the velocity of a particle is v = At + Bt², where A and B are constants, then the distance travelled by it between 1s and 2s is :
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If the magnitude of sum of two vectors is equal to the magnitude of difference of the two vectors, the angle between these vectors is :
|𝐀⃗ + 𝐁⃗| = |𝐀⃗ - 𝐁⃗|
Squaring on both sides
|𝐀⃗ + 𝐁⃗|² = |𝐀⃗ - 𝐁⃗|²
⇒ 𝐀⃗ .𝐀⃗ +2𝐀⃗ .𝐁⃗+𝐁⃗.𝐁⃗
= 𝐀⃗ .𝐀⃗ - 2𝐀⃗ .𝐁⃗+𝐁⃗.𝐁⃗
⇒ 4𝐀⃗ .𝐁⃗ = 0
⇒ 4AB cosθ =0 ⇒ cosθ = 0 ⇒ θ = 90°
A particle moves so that its position vector is given by 𝐫⃗ = cos ωtx̂ + sin ωtŷ. Where ω is a constant . Which of the following is true ?
Position vector
𝐫⃗ = cos ωt x̂ + sin ωt ŷ
Velocity vector, 𝐕⃗= - ωsin t x̂ + ωcos ωt ŷ acceleration vωector,
𝐚⃗ = -ω² cos ωt x̂ - ω² sin ωt ŷ = - ω²𝐫⃗
𝐫⃗ .𝐕⃗ 0 hence 𝐫⃗ ⊥𝐕⃗ and 𝐚⃗ is directed towards the origin.
A car is negotiating a curved road of radius R. The road is banked at an angle θ. The coefficient of friction between the tyres of the car and the road is μₛ. The maximum safe velocity on this road is:
On a banked road,
V²ₘₐₓ/Rg = (μₛ + tanθ/ 1-μₛ tanθ)
Maximum safe velocity of a car on the banked road
Vₘₐₓ = √Rg [μₛ + tanθ/ 1-μₛ tanθ]
What is the minimum velocity with which a body of mass m must enter a vertical loop of radius R so that it can complete the loop ?
√5gR is the minimum velocity which the body must possess at the bottom of the circle so as to go round the circle completely.
A particle of mass 10 g moves along a circle of radius 6.4 cm with a constant tangential acceleration. What is the magnitude of this acceleration if the kinetic energy of the particle becomes equal to 8×10⁻⁴ J by the end of the second revolution after the beginning of the motion?
Given : Mass of particle, M = 10g = 10/1000 kg
radius of circle R= 6.4 cm
Kinetic energy E of particle = 8×10⁻⁴ J
acceleration aₜ = ?
1/2 mv² = E ⇒ 1/2 (10/1000) v² = 8×10⁻⁴
⇒ v² = 16 ×10⁻ ²
⇒ v= 4×10⁻¹ = 0.4 m/s
Now using
v² = u² + 2aₜs (s=4πR)
(0.4) ² = 0² + 2aₜ (4× 22/7 ×6.4/100)
⇒ aₜ = (0.4)² × 7 × 100/ 8×22×6.4=0.1 m/s²
A body of mass 1 kg begins to move under the action of a time dependent force 𝐅⃗=(2tî+3t2ĵ) N, where î and ĵ are unit vectors along x and y axes. What power will be developed by the force at the time t ?
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A uniform circular disc of radius 50 cm at rest is free to turn about an axis which is perpendicular to its plane and passes through its centre. It is subjected to a torque which produces a constant angular acceleration of 2.0 rads⁻². Its net acceleration in ms⁻² at the end of 2.0 s is approximately:
Given, Radius of disc, R= 50 cm
Angular acceleration, a = 2.0 rads⁻²; time t= 2s
Particle at periphery (assume) will have both radial (one) and tangential acceleration
aₜ = Rα = 0.5 ×2 = 1 m/s²
Angular speed ω = ω₀ + αt
ω = 0 + 2 × 2 = 4 rad/sec
Centripetal acceleration a_c = ω²R = (4)² × 0.5 = 16 × 0.5 = 8m/s²
Linear acceleration, aₜ = α.R = 1 m/sec²
Net acceleration, a_total = √(aₜ² + a_c²) = √(1² + 8²) ≈ 8 m/s²
From a disc of radius R and mass M, a circular hole of diameter R, whose rim passes through the centre, is cut. What is the moment of inertia of the remaining part of the disc about a perpendicular axis passing through the centre?
Moment of inertia of complete disc about point ’O’.
I_total disc = MR²/2
Mass of removed disc
M_Removed = M/4 (mass ∝ area)
Moment of inertia of removed disc about point ’O’.
I_Removed (about same perpendicular axis)
= I_cm + mx²
= M/4.(R/2)²/2 + M/4 (R/2)² = 3MR²/32
Therefore the moment of inertia of the remaining part of the disc about a perpendicular axis passing through the centre,
I_Removed disc = I_Total -T _Removed
= MR²/2 - 3/32 MR²= 13/32 MR²
A disk and a sphere of same radius but different masses roll off on two inclined planes of same altitude and length. Which one of the two objects gets to the bottom of the plane first?
Time of descent ∝ K²/R²
Order of value of K²/R²
for disc; K²/R² = 1/2 = 0.5
for sphere; K²/R²= 2/5 = 0.4
(sphere) < (disc)
Sphere reaches first
At what height from the surface of earth the gravitational potential and the value of g are -5.4 ×10⁷ J kg ⁻¹ and 6.0ms⁻² respectively? Take the radius of earth as 6400 km:
As we know, gravitational potential (V) and acceleration due to gravity (g) with height
V= -GM/(R+h) = -5.4 ×10⁷ ...(1)
and g= GM/(R+h)² = 6 ...(2)
Dividing (1) by (2)
-GM/(R+h)/GM/(R+h)² = -5.4 ×10⁷/6
⇒ 5.4 × 10⁷/(R+h) = 6
⇒ (R+h) = 9000 km so, h= 2600 km
The ratio of escape velocity at earth (vₑ) to the escape velocity at a planet (vₚ) whose radius and mean density are twice as that of earth is:
As we know, escape velocity,
vₑ = √2GM/R = √2G/R·(4/3πR³ ρ)
vₑ ∝ R√ρ
vₑ/vₚ = Rₑ/Rₚ.√ρₑ/ρₚ
⇒ vₑ/vₚ = Rₑ/2Rₑ .√ρₑ/2ρₑ
Ratio vₑ/vₚ =1 : 2√2
Two non-mixing liquids of densities ρ and nρ (n>1) are put in a container. The height of each liquid is h. A solid cylinder of length L and density ρ1 is put in this container. The cylinder floats with its axis vertical and length pL (p<1) in the denser liquid. The density ρ1 is equal to:
As we know,
Pressure P= Vdg
Here, LA dg = (pL) A (nρ)g + (1-ρ) LA ρg
⇒ d = (1-p) ρ = [1+ (n-1) p] ρ
Coefficient of linear expansion of brass and steel rods are α₁ and α₂. Lengths of brass and steel rods are ℓ₁ and ℓ₂ respectively. If (ℓ₂−ℓ₁) is maintained same at all temperatures, which one of the following relations holds good?
From question, ( ℓ₂ - ℓ₁) is maintained same at all temperatures hence change in length for both rods should be same i.e., Δ ℓ₁=Δ ℓ₂
As we know, coefficient of linear expansion,
𝛼 = Δℓ/ ℓ₀ΔT
ℓ₁𝛼₁ ΔT = ℓ₂𝛼₂ΔT
ℓ₁𝛼₁ =ℓ₂ 𝛼₂
A black body is at a temperature of 5760 K. The energy of radiation emitted by the body at wavelength 250 nm is U₁, at wavelength 500 nm is U₂, and that at 1000 nm is U₃. Wien’s constant, b = 2.88×10⁶ nmK. Which of the following is correct?
According to Wein’s displacement law, maximum amount of emitted radiation corresponding to λₘ = b/T
λₘ = 2.88 × 10⁶nmK/5760K = 500nm
From the graph U₁<U₂>U₃
A piece of ice falls from a height h so that it melts completely. Only one-quarter of the heat produced is absorbed by the ice and all energy of ice gets converted into heat during its fall. The value of h is: [Latent heat of ice is 3.4×10⁵ J/kg and g=10 N/kg]
According to question only one - quarter of the heat produced by falling piece of ice is absorbed in the melting of ice.
i.e., mgh/4 = mL
⇒ h = 4L/g = 4×3.4×10⁵/10 = 136 km.
A gas is compressed isothermally to half its initial volume. The same gas is compressed separately through an adiabatic process until its volume is again reduced to half. Then:
W_ext = negative of area with volume - axis W (adiabatic) > W (isothermal)
A refrigerator works between 4°C and 30°C. It is required to remove 600 calories of heat every second in order to keep the temperature of the refrigerated space constant. The power required is: (Take 1 cal = 4.2 joules)
Given : T₂ =4°C = 4+ 273 = 277 K
T₁ = 30°C = 30+273 = 303 K
β = Q₂/W = T₂/T₁-T₂
∴ β = 600×4.2/W = 277/303-277
⇒ W = 236.5 joule
Power P = W/t = 236.5/1 sec = 236.5 watt
The molecules of a given mass of gas have r.m.s. velocity of 200 m s⁻¹ at 27°C and 1.0 × 10⁵ Nm⁻² pressure. When the temperature and pressure of the gas are respectively, 127°C and 0.05 × 10⁵ Nm⁻², the r.m.s. velocity of its molecules in m s⁻¹ is:
Here v₁ = 200m/s;
temperature T₁ = 27°C = 27+273 = 300 k
temperature T₂ = 127°C = 127 + 273 = 400k, v₂ = ?
R.M.S.Velocity, v ∝√T
⇒ v₂/200 = √(400/300)
⇒ v₂ = 200×2/√3 m/s ⇒v₂ = 400/√3 m/s
An air column, closed at one end and open at the other, resonates with a tuning fork when the smallest length of the column is 50 cm. The next larger length of the column resonating with the same tuning fork is:
For a closed organ first minimum resonating length
L₁ = λ/4 = 50 cm
Next or second resonating length, L₂
⇒3λ/4 = 150cm
A uniform rope of length L and mass m₁ hangs vertically from a rigid support. A block of mass m₂ is attached to the free end of the rope. A transverse pulse of wavelength λ₁ is produced at the lower end of the rope. The wavelength of the pulse when it reaches the top of the rope is λ₂. The ratio λ₂/λ₁ is
From figure, tension T₁ = m₂g
T₂ = (m₁ + m₂)g (Rigid support)
As we know Velocity ∝ √T
so, λ ∝ √T
⇒ λ₁/λ₂ = √T₁/√T₂
⇒ λ₂/λ₁ = √(m₁+m₂/m₂)
A siren emitting a sound of frequency 800 Hz moves away from an observer towards a cliff at a speed of 15 m s⁻¹. Then, the frequency of sound that the observer hears in the echo reflected from the cliff is: (Take velocity of sound in air = 330 m s⁻¹)
According to Doppler’s effect in sound Apparent frequency,
n′ = (v/v-vₛ) n₀
= 330/330-15 (800) = 330×800/315 = 838 Hz
The frequency of sound observer hears in the echo reflected from the cliff is 838 Hz.
Two identical charged spheres suspended from a common point by two massless strings of lengths l, are initially at a distance d (d≪l) apart because of their mutual repulsion. The charges begin to leak from both the spheres at a constant rate. As a result, the spheres approach each other with a velocity v. Then v varies as a function of the distance x between the spheres, as:
From figure T cos θ = mg
T sin θ = kq²/x²
so, tan θ = Fₑ/mg ≈ θ
tan θ = kq²/x² mg
As θ is small tan θ ≈ sin θ = x/2𝑙
kq²/x² mg = x/2l
or x³ ∝ q² ...(i)
or x³ᐟ² ∝ q ...(ii)
Differentiating eq.(i) w.r.t. time
3x² dx/dt ∝ 2q.dq/dt but dq/dt is constant
so x² (v) ∝ q
Replace q from eq. (ii)
x²(v) ∝ x³ᐟ² or v ∝ x ⁻¹ᐟ²
A capacitor of 2μF is charged as shown in the diagram. When the switch S is turned to position 2, the percentage of its stored energy dissipated is :
When S and 1 are connected
The 2 μF capacitor gets charged. The potential difference across its plates will be V.
The potential energy stored in 2 μF capacitor
Uᵢ = 1/2 CV² = 1/2×2×V² = V²
When S and 2 are connected
The 8 μF capacitor also gets charged. During this charging process current flows in the wire and some amount of energy is dissipated as heat. The energy loss is
ΔU = 1/2 . C₁C₂/C₁C₂ (v₁-v₂)²
Here, C₁ = 2μF, C₂ = 8μF, V₁=V, V₂ =0
ΔU = 1/2 × 2×8/2+8 (V-0)² = 4/5V²
The percentage of the energy dissipated
= ΔU/Uᵢ × 100 = 4/5V² × 100 =80%
The charge flowing through a resistance R varies with time t as Q=at−bt² where a and b are positive constants. The total heat produced in R is:
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A potentiometer wire is 100 cm long and a constant potential difference is maintained across it. Two cells are connected in series first to support one another and then in opposite direction. The balance points are obtained at 50 cm and 10 cm from the positive end of the wire in the two cases. The ratio of e.m.f.s is:
When two cells are connected in series i.e., (E₁ + E₂) the balance point is at 50 cm. And when two cells are connected in opposite direction i.e., (E₁ - E₂) the balance point is at 10 cm. According to principle of potential
E₁+E₂/E₁−E₂=50/10
⇒2E₁/2E₂ = 50+10/50-10 ⇒ E₁/E₂ = 3/2
A long straight wire of radius a carries a steady current I. The current is uniformly distributed over its cross‑section. The ratio of the magnetic fields B and B′, at radial distances a/2 and 2a respectively, from the axis of the wire is:
For points inside the wire i.e., (r ≤ R)
Magnetic field B=μ₀Ir/2πR²
For points outside the wire (r ≥ R)
Magnetic field B/B′ = μ₀I/2πR
∴ B/B' = μ₀I(a/2)/ 2πa²/ μ₀I/2π(2a) = 1:1
A square loop ABCD carrying a current i, is placed near and coplanar with a long straight conductor XY carrying a current I. The net force on the loop will be:
The direction of current in conductor
XY and AB is same
F_AB = ilB (attractive)
F_AB = i(L). μ₀I/2π(L/2) (←) = μ₀iI/π (←)
F_BC opposite to F_AD
F_BC (↑) and F_AD(↓)
⇒ cancels each other
F_CD = ilB (repulsive)
F_CD = i(L) μ₀I/2π(3L/2) (→) = μ₀iI/3π
Therefore the net force on the loop
Fₙₑₜ = F_AB + F_BC + F_CD + F_AD
⇒ Fₙₑₜ = μ₀iI/π - μ₀iI/3π = 2μ₀iI/3π
The magnetic susceptibility is negative for:
Magnetic susceptibility χ for diamagnetic materials only is negative and low ∣χ∣=1; for paramagnetic substances low but positive ∣χ∣=1; and for ferromagnetic substances positive and high ∣χ∣=10².
A long solenoid has 1000 turns. When a current of 4A flows through it, the magnetic flux linked with each turn of the solenoid is 4×10 ⁻³ Wb. The self inductance of the solenoid is:
Here, number of turns n = 1000; current through the solenoid i = 4A; flux linked with each turn = 4 × 10 ⁻³ Wb
⇒ Total flux linked=1000(4×10 ⁻³) = 4 Wb
Φₜₒₜₐₗ = 4 ⇒ Li = 4
⇒ L = 1 H
A small signal voltage V(t)=V₀sinωt is applied across an ideal capacitor C:
As we know, power P = Vᵣₘₛ⋅Iᵣₘₛ⋅cosϕ As cosϕ=0
(∵ ϕ = 90∘)
∴ Power consumed = 0 (in one complete cycle)
An inductor 20 mH, a capacitor 50 μF and a resistor 40Ω are connected in series across a source of emf V=10sin340t. The power loss in A.C. circuit is:
Out of the following options which one can be used to produce a propagating electromagnetic wave?
To generate electromagnetic waves we need accelerating charge particle.
Match the corresponding entries of column‑1 with column‑2 (Where m is the magnification produced by the mirror):
Magnitude m=+ve ⇒ virtual image
m=−ve ⇒ real image
Magnitude of magnification:
∣m∣>1 ⇒ magnified image
∣m∣<1 ⇒ diminished image
The angle of incidence for a ray of light at a refracting surface of a prism is 45°. The angle of prism is 60°. If the ray suffers minimum deviation through the prism, the angle of minimum deviation and refractive index of the material of the prism respectively, are:
Given: Angle of incidence i = 45°
Angle of prism, A = 60°
Angle of minimum deviation:
δₘ = 2i − A = 30°
Refractive index of material of prism:
μ = sin (A+δₘ/2) / sin (A/2)
= sin 45°/sin 30° = 1/√2 · (2/1) = √2
An astronomical telescope has objective and eyepiece of focal lengths 40 cm and 4 cm respectively. To view an object 200 cm away from the objective, the lenses must be separated by a distance:
Given: Focal length of objective, f₀ = 40 cm
Focal length of eye‑piece, fₑ = 4 cm
Image distance, v₀ = 200 cm
Using lens formula for objective lens:
1/v₀ - 1/u₀ = 1/f₀ ⇒ 1/v₀ = 1/f₀+1/u₀
⇒ 1/v₀ = 1/40 + 1/-200 = +5-1/200
⇒ v₀ = 50cm
Tube length 𝑙 = v₀ + fₑ = 50+4 = 54cm.
The intensity at the maximum in a Young's double slit experiment is I₀. Distance between two slits is d = 5λ, where λ is the wavelength of light used in the experiment. What will be the intensity in front of one of the slits on the screen placed at a distance D = 10d?
Let P is a point in front of one slit at which intensity is to be calculated. From figure path difference = S₂P-S₁P
= √(D²+d²) - D = D(1+1/2.d²/D²)-D
= D[1+d²/2D²-1] = d²/2D
Δx = d²/2×10d = d/20 = 5λ/20 = λ/4
Phase difference,
ΔΦ = 2π/λ × λ/4 = π/2
So, resultant, intensity at the desired point ’p’ is
I = I₀cos²Φ/2= I₀cos²π/4=I₀/2
In a diffraction pattern due to a single slit of width 'a', the first minimum is observed at an angle 30° when light of wavelength 5000 Å is incident on the slit. The first secondary maximum is observed at an angle of:
For the first minima,
θ=ηλ/a ⇒ sin30°=λ/a=1/2
First secondary maxima will be at
sinθ=3λ/2a=3/2(1/2)⇒ θ=sin⁻¹ (3/4)
An electron of mass m and a photon have same energy E. The ratio of de-Broglie wavelengths associated with them is:
For electron De-Broglie wavelength,
λₑ = h/√2mE
For photon E = pc
⇒De-Bronglie wavelength, λₚₕ = hc/E
λₑ/λₚₕ = h/√2mE × E/hc = (E/2m)¹ᐟ² 1/c
When a metallic surface is illuminated with radiation of wavelength λ, the stopping potential is V. If the same surface is illuminated with radiation of wavelength 2λ, the stopping potential is V/4. The threshold wavelength for the metallic surface is:
According to Einstein’s photoelectric effect,
eV= hc/λ-hc/λ₀ ...(i)
eV/4 = hc/2λ-hc/λ₀ ...(ii)
Dividing equation (i) by (ii) by
⇒ 4 = 1/λ-1/λ₀ / 1/2λ-1/λ₀ on solving we get,
λ₀ =3λ
When an α-particle of mass 'm' moving with velocity 'v' bombards on a heavy nucleus of charge 'Ze', its distance of closest approach from the nucleus depends on m as:
At closest distance of approach, the kinetic energy of the particle will convert completely into electrostatic potential energy.
Kinetic energy K.E. = 1/2 mv²
Potential energy P.E. = KQq/r
1/2 mv² = KQq/r
⇒ r ∝ 1/m
Given the value of Rydberg constant is 10⁷ m ⁻¹, the wave number of the last line of the Balmer series in hydrogen spectrum will be:
According to Bohr's theory, the wave number of the last line of the Balmer series in hydrogen spectrum, For hydrogen atom Z=1
1/λ = RZ² (1/n₂² - 1/n₁²)
=10⁷ × 1² (1/2² -1/∞²)
⇒wave number 1/λ = 0.25 × 10⁷ m⁻¹
Consider the junction diode as ideal. The value of current flowing through AB is:
Since Diode is in forward bias, so the value of current flowing through AB
i = Δv/R = 4-(-6)/1×10³ = 10⁻²A
A npn transistor is connected in common emitter configuration in a given amplifier. A load resistance of 800Ω is connected in the collector circuit and the voltage drop across it is 0.8V. If the current amplification factor is 0.96 and the input resistance of the circuit is 192Ω, the voltage gain and the power gain of the amplifier will respectively be:
Given: amplification factor α = 0.96
Load resistance, R_L = 800 Ω
Input resistance, Rᵢ = 192 Ω
So, β = α/1-α = 0.96/0.04 ⇒ β = 24
Voltage gain for common emitter configuration
Aᵥ = β.R_L/Rᵢ = 24×800/192 = 100
Power gain for common emitter configuration
Pᵥ = βAᵥ = 24 × 100 = 2400
Voltage gain for common base configuration
Aᵥ = α, R_L/Rₚ = 0.96×800/192=4
Power gain for common base configuration
Pᵥ = Aᵥα = 4×0.96 = 3.84
To get output 1 for the following circuit, the correct choice for the input is:
The Boolen expression for the given combination is output Y=(A+B).C
Two electrons occupying the same orbital are distinguished by
Two electrons occupying the same orbital should have opposite spins i.e. they differ in spin quantum number.
In which of the following options the order of arrangement does not agree with the variation of property indicated against it?
The correct order is B < C < O < N
Generally ionisation energy increases across a period. But here first I.E. of O is less than the first I.E. of N. This is due to the half‑filled 2p orbital in N (1s², 2s², 2p³) which is more stable than the 2p orbital in O (1s², 2s², 2p⁴).
Consider the molecules CH₄, NH₃ and H₂O. Which of the given statements is false?
Predict the correct order of electron repulsion among the following:
According to VSEPR theory order of repulsion in between lp – lp, lp – bp and bp – bp is as under lp – lp > lp – bp > bp – bp
Equal moles of hydrogen and oxygen gases are placed in a container with a pin‑hole through which both can escape. What fraction of the oxygen escapes in the time required for one‑half of the hydrogen to escape?
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The correct thermodynamic conditions for the spontaneous reaction at all temperatures is
ΔG=ΔH–T⋅ΔS
For a spontaneous reaction ΔG= –ve (always)
which is possible only if
ΔH < 0 and ΔS > 0
∴ spontaneous at all temperatures.
Consider the following liquid‑vapour equilibrium.
Liquid ⇌ Vapour
Which of the following relations is correct?
Clausius–Clapeyron's equation
dlnP/dT=ΔHᵥ/RT²
MY and NY₃, two nearly insoluble salts, have the same Ksp values of 6.2 × 10⁻¹³ at room temperature. Which statement would be true in regard to MY and NY₃?
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Consider the nitration of benzene using mixed conc of H₂SO₄ and HNO₃. If a large amount of KHSO₄ is added to the mixture, the rate of nitration will be
The presence of large amount of KHSO₄ will decrease ionisation of H2SO₄, resulting in lesser ionisation of nitric acid and lesser formation of nitronium ion [NO⁺₂]. Hence the rate of nitration will be slower.
Which of the following statements about hydrogen is incorrect?
Among the three isotopes of hydrogen, Protium (¹₁H) is most common. It is an energetic reducing agent. It reduces oxides, chlorides and sulphides of certain metals and produces free metals at ordinary temperature.
CuO + 2H → Cu + H₂O
Which of the following statements is false?
Calcium regulates muscle contraction, including beating of heart muscle, so that it can contract and pump out blood to all our body.
The pair of electron in the given carbanion, CH₃C ≡ C⁻, is present in which of the following orbitals?
CH₃—C ≡ C⁻⊖
No. of σ bp = 1
lp = 1
2 & hybridisation is sp
The correct statement regarding the comparison of staggered and eclipsed conformation of ethane, is
In staggered conformation any two hydrogen atoms on adjacent carbon atoms are as far apart as possible, thereby minimising repulsion between the electron clouds of σ‑bonds of two non‑bonded H‑atoms (torsional strain).
In the reaction
X and Y are
.
Which of the following statement about the composition of the vapour over an ideal 1 : 1 molar mixture of benzene and toluene is correct? Assume that the temperature is constant at 25°C. (Given: Vapour pressure data at 25°C, benzene = 12.8 kPa, toluene = 3.85 kPa)
Let us consider that A is benzene and B is toluene 1:1 molar mixture of A and B
x_A = 1/2 and x_B = 1/2
Total Pressure of solution (P) P⁰_A x_A + P⁰_B x_B
P= 12.8 × 1/2 + 3.85×1/2 = 8.325 kPa
y_A = P⁰_A x_A/P = (12.8× 1/2)/ 8.325 = 0.768
y_B = 1-y_A = 1-0.768=0.232
so, the vapour will contain higher percentage of benzene
At 100°C the vapour pressure of a solution of 6.5 g of a solute in 100 g water is 732 mm. If Kb = 0.52, the boiling point of this solution will be
(P°-Pₛ/P°) = n/N = W₁/M₁ × M₂/W₂
Where, W₁ = wt of solute
W₂ = wt of solvent
M₁ = Mass of solute
M₂ = Mass of solvent
at 100°C, P°=760 mm
760-732/760= 6.5×18/M₁×100
M₁ = 31.75g mol⁻¹
ΔT_b m×K_b = (W₁×1000/M₁ ×W₂) ×K_b
ΔT_b = (0.52×6.5×1000/31.75×100)=1.06 °C
boiling point of solution
= 100 °C + 1.06 °C = 101 °C
The pressure of H₂ required to make the potential of H₂‑electrode zero in pure water at 298 K is:
2H⁺ (aq) + 2e⁻ → H₂(g)
E = E° - 0.0591/2 log P_H₂/ [H⁺]²
0 = 0- 0.0295 log P_H₂/ (10⁻⁷)²
P_H₂/(10⁻⁷)² = 1
P_H₂ = 10⁻¹⁴atm
The rate of a first‑order reaction is 0.04 mol l⁻¹ s⁻¹ at 10 seconds and 0.03 mol l⁻¹ s⁻¹ at 20 seconds after initiation of the reaction. The half‑life period of the reaction is
For a first order reaction
K= 2.303/(t₂-t₁) log (a-x₁/a-x₂)
K= 2.303 / (20-10) log (0.04/0.03)
K = 2.303 × 0.1249/10
0.6932/t₁/₂ = 2.303×0.1249/10
t₁/₂ = 0.6932 ×10 / 2.303×0.1249=24.1 sec
The addition of a catalyst during a chemical reaction alters which of the following quantities?
A catalyst provides an alternative route for the reaction with a lower activation energy.
Which one of the following characteristics is associated with adsorption?
Adsorption is spontaneous process, therefore change in the free energy (ΔG) for the process is negative. According to Gibbs Helmholtz equation,
ΔG=ΔH−TΔS
ΔS is negative because adhering of gas molecules to the surface lowers the randomness. ∴ ΔG can be –ve only when ΔH is –ve.
Fog is colloidal solution of
Fog is a colloidal system having dispersed phase as liquid and dispersion medium as gas.
Which is the correct statement for the given acids?
Phosphinic acid as shown in structure below has one P–OH bond, thus, it is monobasic or monoprotic.
The product obtained as a result of a reaction of nitrogen with CaC₂ is
CaC₂ + N₂ → CaCN₂ + C
Among the following, the correct order of acidity is
Acidic strength increases as the oxidation number of central atom increases.
Which one of the following orders is correct for the bond dissociation enthalpy of halogen molecules?
Bond dissociation enthalpy decreases as the bond distance increases from F₂ to I₂. This is due to increase in the size of the atom, on moving from F to I. F–F bond dissociation enthalpy is smaller than Cl–Cl and even smaller than Br–Br. This is because F atom is very small and hence the three lone pairs of electrons on each F atom repel the bond pair holding the F‑atoms in F₂ molecules. The increasing order of bond dissociation enthalpy is I₂ < F₂ < Br₂ < Cl₂
Match the compounds given in column I with the hybridisation and shape given in column II and mark the correct option.
Which one of the following statements is correct when SO₂ is passed through acidified K₂Cr₂O₇ solution?
K₂Cr₂O₇ + SO₂ + H₂SO₄
→ K₂SO₄ + Cr₂(SO₄)₃ + H₂O
green colour
When copper is heated with conc. HNO₃ it produces
Less active metals like Cu, Ag etc. react with conc. acid and form nitrate and nitrogen dioxide.
The electronic configurations of Eu (Atomic No. 63), Gd (Atomic No. 64) and Tb (Atomic No. 65) are
Eu (63) = [Xe] 4f⁷ 6s² Gd (64) = [Xe] 4f⁷ 5d¹ 6s² Tb (65) = [Xe] 4f⁹ 6s²
Which of the following has longest C–O bond length? (Free C–O bond length in CO is 1.128 Å)
[Fe(CO)₄]²⁻ Since metal atom is carrying maximum –ve charge therefore, it would show maximum synergic bonding as a resultant C—O bond length would be maximum.
For the following reactions :
Which of the following statements is correct?
.
Which of the following biphenyls is optically active?
-
(A) a
-
(B) d
-
(C) b
-
(D) c
In option (a), there is no chiral carbon.
In option (c), there exist a center of symmetry.
In option (d), there exist a plane of symmetry.
In option (d), both the rings are not in the same plane and the rotation is restricted around the single bond.
Which of the following reagents would distinguish cis‑cyclopentane‑1,2‑diol from the trans‑isomer?
.
The reaction
Can be classified as:-
This is an example of Williamson ether synthesis reaction in which sodium alkoxide reacts with alkyl halide and gives ether.
The correct statement regarding a carbonyl compound with a hydrogen atom on its alpha‑carbon, is:
Keto‑enol tautomerism is possible only in those aldehydes and ketones which have at least one α‑hydrogen atom, which can convert the ketonic group to the enolic group. e.g.
The product formed by the reaction of an aldehyde with a primary amine is
Schiff base is formed when 1° amine reacts with aldehydes.
The correct statement regarding the basicity of arylamines is
Arylamines are generally less basic than alkylamines due to following factors: (i) Due to resonance in aromatic amines. (ii) Lower stability of anilinium ion.
Which one given below is a non‑reducing sugar?
Sucrose is non‑reducing disaccharide as the two monosaccharide units are linked through their respective carbonyl groups.
In a protein molecule various amino acids are linked together by
Peptide bond
The correct statement regarding RNA and DNA, respectively is
Sugar in DNA is 2‑deoxyribose whereas sugar in RNA is ribose.
Natural rubber has
Natural rubber is found to be a polymer of cis‑isoprene i.e. it is cis‑polyisoprene
Which of the following is an analgesic?
Novalgin is most widely used as analgesic. Analgesics are pain relieving.
Match items of Column I with the items of Column II and assign the correct code:
Highly electropositive metals like Al, K, Na etc. are extracted by the electrolytic reduction.
• Zone refining method is used for obtaining metals of high purity e.g. Ge
• Froth flotation process is suitable for sulphide ores
• Cyanide process is used for the extraction of gold.
Lithium has a bcc structure. Its density is 530 kg m⁻³ and its atomic mass is 6.94 g mol⁻¹. Calculate the edge length of a unit cell of Lithium metal. (Nₐ = 6.02 × 10²³ mol⁻¹)
density (ρ) = Z×M/N_A × a³
For bcc structure
Z=2, ρ=530 kg⁻³ = 0.530g cm⁻³
a³ =4.348×10⁻²³ cm³
a= 3.52×10⁻⁸ cm
a= 352 pm
The ionic radii of A⁺ and B⁻ ions are 0.98 × 10⁻¹⁰ m and 1.81 × 10⁻¹⁰ m. The coordination number of each ion in AB is
Radii ratio= r₊/r₋ = 0.98×⁻¹⁰/ 1.81×10⁻¹⁰ = 0.54
Since, the radii ratio is between 0.414 to 0.732 so, coordination number is 6.
It is much easier for a small animal to run uphill than for a large animal, because
Basal metabolic rate is inversely proportional to body size. So, smaller animals have a higher metabolic rate. Hence production of energy is more.
Nomenclature is governed by certain universal rules. Which one of the following is contrary to the rules of nomenclature?
Binomial nomenclature is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages.
Chrysophytes, Euglenoids, Dinoflagellates and Slime moulds are included in the kingdom
All unicellular eukaryotic organism like diatoms, desmids (chrysophytes), euglenoids, dinoflagellates and slime mould are included in Protista.
One of the major components of cell wall of most fungi is
A cell wall is a rigid structural layer, which provides protection and structural support to the cells. The composition of cell wall varies from one species to another. In fungi, the cell wall is composed of strong covalent linkages of chitin, glucans and glycoproteins. Alternatively, in case of land plants, the cell wall is composed of cellulose and hemicellulose. Archean cell walls consists of peptidoglycans.
Which one of the following statements is wrong?
Eubacteria are the true bacteria.
Which of the following statements is wrong for viroids?
Viroids, the smallest known pathogens, are naked, circular, single‑stranded RNA molecules that do not encode protein but autonomously replicate when introduced into host plants. Viroids only infect plants; some cause economically important diseases of crop plants, while others appear to be benign.
In bryophytes and pteridophytes, transport of male gametes requires
Bryophytes neither have pollen nor flowers and rely on water to carry the male gametes (sperm) to the female gametes (eggs). The antherozoids (male gametes of pteridophytes) are armed with hair‑like or whip‑like cilia or flagellae and are able to swim through water; they do not travel great distances and are only released when free water is available.
Select the correct statement:
Sequoia sempervirens is one of the tallest trees.
Which of the following features is not present in the Phylum – Arthropoda?
All arthropods possess a stiff exoskeleton (external skeleton) composed primarily of chitin. Arthropod bodies are divided into segments. Parapodia are paired, lateral appendages extending from the body segments. Arthropod appendages may be either biramous (branched) or uniramous (unbranched). They possess jointed appendages.
Which of the following characteristic features always holds true for the corresponding group of animals?
Chondrichthyes always have cartilaginous endoskeleton. Most mammals are viviparous, giving birth to young. However, the five species of monotreme, the platypuses and the echidnas, lay eggs. Chondrichthyes have jawless animals (Agnatha) as well. Most reptiles have a 4 chambered heart. Crocodilians have 4 chambered heart. Turtles have 3 chambered heart but with an incomplete wall in the single ventricle, so their hearts are functionally 4 chambered.
Which one of the following characteristics is not shared by birds and mammals?
Giving birth to young that develop within the mother’s body rather than hatching from eggs. All mammals except the monotremes are viviparous.
Stems modified into flat green organs performing the functions of leaves are known as
Phylloclade refers to a portion of a flattened leaf‑like stem or branch with multiple nodes and internodes, and cladode for a single internode of a phylloclade. In some plants, the petioles are flattened and widened, to become phyllodes or phyllodia.
The standard petal of a papilionaceous corolla is also called
Papilionaceous flowers are flowers with the characteristic irregular and butterfly‑like corolla. A single, large upper petal is known as the banner or vexillum and the name has been derived from an ancient military standard.
Proximal end of the filament of stamen is attached to the
The proximal end is attached to the thalamus whereas the distal end bears anther.
The coconut water from tender coconut represents
Coconut water is the clear liquid inside young green coconuts (fruits of the coconut palm). In early development, it serves as a suspension for the endosperm of the coconut during the nuclear phase of development. As growth continues, the endosperm matures into its cellular phase and deposits into the rind of the coconut meat.
Cotyledon of maize grain is called
The cotyledons are known as seed leaves, they are attached to the embryonic axis. Dicotyledons typically have two cotyledons and monocotyledons have only one cotyledon. The single shield‑shaped cotyledon in grains known as scutellum.
Tricarpellary syncarpous gynoecium is found in flowers of
The Liliaceae are a huge variety, comprising about 280 genera and 4000 species of perennial herbs mostly. It includes starchy rhizomes, corms or bulbs, characterized by alternate leaves which are whorled. The flowers are often showy, mostly bisexual and actinomorphic. Also, they exhibit tricarpellary syncarpous gynoecium. Example of such a class is the Erythronium montanum, the alpine fawn lily.
Which type of tissue correctly matches with its location?
Wall of intestine is made of smooth muscle. Tendons consist of dense regular connective tissue fascicles encased in dense irregular connective tissue sheaths. Tip of nose consists of squamous epithelium. Lining of epithelium is made of columnar epithelium.
Which of the following features is not present in Periplaneta americana?
Periplanata americana shows spiral and determinate types of cleavage during embryonic development which is a feature of Protostomes.
Mitochondria and chloroplast are (A) semi‑autonomous organelles (B) formed by division of pre‑existing organelles and they contain DNA but lack protein synthesizing machinery
Which one of the following options is correct?
Mitochondria & chloroplast are semi‑autonomous cell organelle which are formed by division of pre‑existing organelle & contain DNA but they also contain protein synthesizing machinery, thus (a) is true & (b) is false.
Microtubules are the constituents of
Roles of the microtubule cytoskeleton include mechanical support, organization of the cytoplasm, transport, motility and chromosome segregation so they are present in cilia and flagella for cellular movement, centrioles for chromosomal movement and spindle fibres for structural organization as well as chromosomal movement during nuclear division.
Which one of the following cell organelles is enclosed by a single membrane?
Double Membrane bound Organelles: Mitochondria, Chloroplasts, Endoplasmic Reticulum, Golgi Body, and Nucleus. Single Membrane bound Organelles: Lysosomes, Peroxisomes, and Vacuoles. Organelles lacking any membrane: Ribosomes, Centrioles, Nucleolus.
The two polypeptides of human insulin are linked together by
Insulin is a hormone consisting of 2 polypeptide chains. Each chain is composed of a specific sequence of amino acid residues connected by peptide bonds. In humans, chain A has 21 amino acids, and chain B has 30. Post translational modifications result in the connection of these two chains by disulfide bridges.
The amino acid Tryptophan is the precursor for the synthesis of
Tryptophan is a precursor to neurotransmitters serotonin and melatonin. Thyroxine (3,5,3',5'-tetraiodothyronine) is produced by follicular cells of the thyroid gland. It is produced as the precursor thyroglobulin. Estrogen is biosynthesized from progesterone (in two steps from cholesterol, via intermediate pregnenolone). Cortisone is one of several end-products of a process called steroidogenesis. Cortisol is produced in the adrenal cortex of kidney.
Which one of the following statements is wrong?
Glycine (abbreviated as Gly or G) is the smallest of the 20 amino acids commonly found in proteins, and indeed is the smallest possible (having a hydrogen substituent as its side-chain). The formula is NH₂CH₂COOH. Its codons are GGU, GGC, GGA, GGG of the genetic code.
Spindle fibres attach on to
Attachment of microtubules to chromosomes is mediated by kinetochores, which actively monitor spindle formation and prevent premature anaphase onset during mitosis.
Which of the following is not a characteristic feature during mitosis in somatic cells?
Synapsis is the pairing of two homologous chromosomes that occurs during meiosis. It allows matching-up of homologous pairs prior to their segregation, and possible chromosomal crossover between them. Synapsis takes place during prophase I, of zygotene of meiosis.
In meiosis crossing over is initiated at
Meiosis is a process (discovered by German biologist, Oscar Hertwig) where a single cell divides twice to produce four cells containing half the original amount of genetic information. These cells are our sex cells – sperm in males, eggs in females. Crossing over is the process by which two chromosomes exchange some distal part of their DNA. This process occurs in the Pachytene stage of Prophase I of meiosis.
Water vapour comes out from the plant leaf through the stomatal opening. Through the same stomatal opening carbon dioxide diffuses into the plant during photosynthesis. Reason out the above statements using one of following options
In actively growing plants, water is continuously evaporating from the surface of leaf cells through stomatal opening exposed to air. This is called transpiration. Through the same stomatal opening carbon dioxide diffuses into the plant during photosynthesis simultaneously, as both are processes of simple diffusion occurring in order of diffusion pressure gradient or diffusion coefficient.
In which of the following, all three are macronutrients?
Nitrogen, phosphorus, potassium, calcium, sulfur, and magnesium are the macronutrients. The essential elements can be divided into macronutrients and micronutrients. Nutrients that plants require in larger amounts are called macronutrients. About half of the essential elements are considered macronutrients: carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur.
In a chloroplast the highest number of protons are found in
Proton concentration is higher in the lumen of thylakoid due to photolysis of water, H⁺ pumping and NADP reductase activity in stroma. During the light-dependent reaction, protons are pumped across the thylakoid membrane into the lumen making it acidic down to pH 4.
Water soluble pigments found in plant cell vacuoles are
Many leaves produce water-soluble vacuolar pigments, which are stored within cell vacuoles (microscopic water sacs within each cell). Two major classes of leaf vacuolar pigments are anthocyanins and betalains.
Emerson’s enhancement effect and Red drop have been instrumental in the discovery of
Emerson performed photosynthetic experiment. On Chlorella, he provided monochromatic light of more than 680 nm and observed decrease in rate of photosynthesis known as red drop. Later, he provides synchronised light of 680 nm and 700 nm and observed increase in rate of photosynthesis known as enhancement effect. This experiment led to discovery of two photosystems—PS-I and PS-II operating in photosynthesis.
A plant in your garden avoids photorespiratory losses, has improved water use efficiency, shows high rates of photosynthesis at high temperatures and has improved efficiency of nitrogen utilisation.
In which of the following physiological groups would you assign this plant?
C₄ plants are adapted to hot and dry climate and lack photorespiration due to Kranz anatomy and have greater productivity of biomass.
The Avena curvature is used for bioassay of
Auxin has been clearly demonstrated in the leaf sheath or coleoptile of oat plant (Avena sativa). This plant coleoptile has been used for the test of hormone Auxin (IAA) participating in the growth of the plant.
Which of the following guards the opening of hepatopancreatic duct into the duodenum?
The sphincter of Oddi (or hepatopancreatic sphmcler)
is a muscular valve that controls the flow of digestive juices (bile and pancreatic juice) through the ampulla of Vater into the second part of the duodenum.
In the stomach, gastric acid is secreted by the
The main constituent of gastric acid is hydrochloric acid which is produced by parietal cells (also called oxyntic cells) in the gastric glands in the stomach.
Name the chronic respiratory disorder caused mainly by cigarette smoking
Emphysema results when the delicate linings of the air sacs in the lungs become damaged beyond repair. Most commonly, the toxins in cigarette smoke create the damage. Emphysema is called smoker’s disease.
Reduction in pH of blood will
Reduction of pH of blood will decrease the affinity of haemoglobin with oxygen which in turn causes acidosis.
Blood pressure in the pulmonary artery is
Arteries have higher blood pressure than veins because blood is forced inside them from heart and also their lumen is narrow.
In mammals, which blood vessel would normally carry largest amount of urea?
Hepatic Vein, because the liver produces urea and other waste materials and then pours it all in the right ventricle of the heart for oxygenation. The heart distributes the blood to various parts of the body from here. So the impure blood brought by the Hepatic Vein and other blood vessels get distributed through the aorta. This will automatically imply that the Renal Artery will contain lesser impure blood than the Hepatic Vein.
Lack of relaxation between successive stimuli in sustained muscle contraction is known as
Sustained contraction with no relaxation phase is called muscle tetanus.
Photosensitive compound in human eye is made up of
Retinal is also known as retinaldehyde. It was originally called retinene, and renamed afterwards it was discovered to be vitamin A aldehyde. Retinal is one of the many forms of vitamin A (the number of which varies from species to species). Retinal is a polyene chromophore, bound to proteins called opsins, and is the chemical basis of animal vision.
Which of the following pairs of hormones are not antagonistic (having opposite effects) to each other?
Calcitonin exerts its effects by interacting with target cells, primarily in bone and kidney. The actions of PTH and calcitonin are antagonistic on bone resorption but synergistic on decreasing the renal tubular reabsorption of phosphorus. Insulin and glucagon work synergistically to keep blood glucose concentrations normal. An elevated blood glucose concentration results in the secretion of insulin and glucose is transported into body cells. Aldosterone secretion may be inhibited by potassium depletion, inhibitors of the renin-angiotensin system, dopamine and atrial natriuretic factor. The latter appears to be an important physiological regulator of aldosterone secretion. ANF inhibits basal, ACTH, Angiotensin II and potassium-stimulated aldosterone production in vitro by a direct action on the adrenal gland. Inhibin is a hormone secreted by granulosa cells of the ovary which inhibit the secretion of FSH (Follicle Stimulating Hormone) whereas relaxin produced by ovary and placenta and the childbirth to softens the ligament in the pelvis and widens the cervix.
Changes in GnRH pulse frequency in females is controlled by circulating levels of
At the pituitary, GnRH stimulates the synthesis and secretion of the gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone (LH). These processes are controlled by the size and frequency of GnRH pulses, as well as by feedback from progesterone and estrogens. Low-frequency GnRH pulses are required for FSH release, whereas high-frequency GnRH pulses stimulate LH pulses in a one-to-one manner.
Identify the correct statement on ‘inhibin’
In both females and males, inhibin inhibits FSH production. In females, FSH stimulates the secretion of inhibin from the granulosa cells of the ovarian follicles in the ovaries. In turn, inhibin suppresses FSH. In males, androgens stimulate inhibin production. It is secreted from the Sertoli cells, located in the seminiferous tubules inside the testes.
Seed formation without fertilization in flowering plants involves the process of:
Apomixis is defined as the asexual formation of seed from the maternal tissues of the ovule, avoiding the process of meiosis and fertilisation, leading to the development of the embryo.
Which one of the following statements is not true?
Tapetum is important for the nutrition and development of pollen grains, as well as a source of precursors for the pollen coat.
Which of the following statements is not correct?
Pollen grains of different species are incomplete so they fail to germinate. If the pollen-stigma interaction is compatible, the pollen grain hydrates and germinate shortly following landing on the stigma.
Fertilization in humans is practically feasible only if
The word ampulla is derived from the Latin word ‘flask’. Being the second portion of the fallopian tube, it is the intermediate dilated portion which immediately overlays the ovary. This is the common site of human fertilization as both the ovum and sperm are simultaneously transported here.
Select the incorrect statement:
Ovulation is the process of the monthly release of the viable oocyte from the ovary between the time of menarche and menopause. During this time, there is a surge in the production of LH and FSH, termed as gonadotropins, thereby initiating estradiol and progesterone secretion from the ovary. Both the hormones are play an important in the menstrual cycle.
In context of Amniocentesis, which of the following statement is incorrect?
Amniocentesis (also referred to as amniotic fluid test or AFT) is a medical procedure used in prenatal diagnosis of chromosomal abnormalities and fetal infections, and also used for sex determination in which a small amount of amniotic fluid, which contains fetal tissues, is sampled from the amniotic sac. Cleft palate is a developmental abnormality which can only be detected by sonography.
Which of the following approaches does not give the defined action of contraceptive?
Vasectomy is a surgical procedure for male sterilization or permanent contraception. During the procedure, the male vas deferens are severed and then tied or sealed in a manner so as to prevent sperm from entering into the seminal stream (ejaculate) and thereby prevent fertilization.
A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the F₁ plants were selfed the resulting genotypes were in the ratio of
.
In a testcross involving F, dihybrid flies, more parental type offspring were produced than the recombinant type offspring.
This indicates
When two genes in a dihybrid cross are situated on the same chromosome, the proportion of parental gene combinations are much higher than the non-parental or recombinant type. This is also called incomplete linkage.
A cell at telophase stage is observed by a student in a plant brought from the field. He tells his teacher that this cell is not like other cells at telophase stage. There is no formation of cell plate and thus the cell is containing more number of chromosomes as compared to other dividing cells. This would result in
This phenomenon is known as polyploidy, wherein the cells contain more than two paired (homologous) sets of chromosomes. Polyploidy is often seen in the case of plants. The major cause of polyploidy is the non-disjunction of sister chromatids during meiotic recombination. This condition is actually useful in development of new crop varieties.
Which of the following most appropriately describes haemophilia?
Haemophilia A and haemophilia B are inherited in an X-linked recessive pattern. The genes associated with these conditions are located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, it is very rare for females to have haemophilia. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.
Pick out the correct statements:
(1) Haemophilia is a sex‑linked recessive disease
(2) Down’s syndrome is due to aneuploidy
(3) Phenylketonuria is an autosomal recessive gene disorder
(4) Sickle cell anaemia is a X‑linked recessive gene disorder
Sickle cell disease is inherited in an autosomal recessive pattern.
A complex of ribosomes attached to a single strand of RNA is known as
A polysome or polyribosome is a complex of an mRNA molecule and two or more ribosomes, which is formed during the active translation process. They were initially named as ergosomes in 1963. However, further research by Jonathan Warner and Alex Rich characterized polysomes.
Which one of the following is the starter codon?
The startcodon is the first codon of a messenger RNA (mRNA) transcript translated by a ribosome. The start codon always codes for methionine in eukaryotes and a modified Met (fMet) in prokaryotes. The most common start codon is AUG.
Which of the following is required as inducer(s) for the expression of Lac operon?
Lac operon is an inducible operon. Lactose is the substrate for the enzyme beta-galactosidase and it also regulates switching on and off of the operon. Hence, it is termed as inducer. Inducer functions by disabling repressors. The gene is expressed because an inducer binds to the repressor. The binding of the inducer to the repressor prevents the repressor from binding to the operator. RNA polymerase can then begin to transcribe structural genes.
Which of the following is not required for any of the techniques of DNA fingerprinting available at present ?
Zinc‑finger analysis is used for protein analysis. The zinc finger proteins are a super family of proteins involved in numerous activities of plant growth and development.
Which of the following structures is homologus to the wing of a bird?
Wings of a bird and flippers of a whale are modified forelimbs.
Following are the two statements regarding the origin of life
(A) The earliest organisms that appeared on the earth were non‑green and presumably anaerobes.
(B) The first autotrophic organisms were the chemoautotrophs that never released oxygen.
Of the above statements which one of the following options is correct?
Both statements are correct because primitive atmosphere was reducing and chlorophyll appeared later on. Chemoautotrophs were the first autotrophic organisms unable to perform photolysis of water and never released oxygen.
Analogous structures are a result of
Analogous structures are those that have the same function, but they are not derived from a common ancestor and have undergone different patterns of development i.e., Convergent evolution which is natural selection that favors the same type of structure in different ancestors.
In higher vertebrates, the immune system can distinguish self‑cells and non‑self. If this property is lost due to genetic abnormality and it attacks self‑cells, then it leads to
An autoimmune disease is a pathological state arising from an abnormal immune response of the body to substances and tissues that are normally present in the body.
Antivenom injection contains preformed antibodies while polio drops that are administered into the body contain
Oral Polio Vaccine consists of a mixture of attenuated (weakened) poliovirus strains of all three poliovirus types.
Which of the following statements is not true for cancer cells in relation to mutations?
Telomerase production is increased in cancer. Telomerase has been examined in hundreds of studies as a potentially sensitive biomarker for screening, early cancer detection, prognosis or in monitoring as an indication of residual disease.
The enzyme telomerase adds TTAGGG repeats onto mammalian telomeres, which prevents their shortening. The activation of telomerase in malignant cancers seems to be an important step in tumorigenesis, whereby the cell gains the ability of indefinite proliferation to become immortal.
A system of rotating crops with legume or grass pasture to improve soil structure and fertility is called
The growing of grass or legumes in rotation with grain or tilled crops as a soil conservation measure is called Ley farming.
Which part of the tobacco plant is infected by Meloidogyne incognita?
Meloidogyne incognita is a nematode (roundworm) in the family Heteroderidae. It is commonly called the “southern root‑knot nematode” or the “cotton root‑knot nematode”.
Which of the following is wrongly matched in the given table?
Clostridium butylicum is used for butyric acid production.
The primitive prokaryotes responsible for the production of biogas from the dung of ruminant animals, include the
Methanogens are microorganisms that produce methane as a metabolic byproduct in anoxic conditions. They are obligate anaerobic ancient and primitive bacteria. They are involved in methanogenesis.
Which of the following is not a feature of the plasmids?
Plasmid is an extra chromosomal, double‑stranded circular DNA.
The taq polymerase enzyme is obtained from
The Taq polymerase enzyme is obtained from Thermus aquaticus which lives in hot springs.
Which of the following is a restriction endonuclease?
A restriction enzyme or restriction endonuclease is an enzyme that cuts DNA at or near specific recognition nucleotide sequences known as restriction sites. Hind II among these is a type of restriction endonuclease.
Which part of the tobacco plant is infected by Meloidogyne incognita?
Meloidogyne incognita is a nematode (roundworm) in the family Heteroderidae. It is commonly called the “southern root‑knot nematode” or the “cotton root‑knot nematode”.
Gause’s principle of competitive exclusion states that:
Gause’s principle of competitive exclusion can be restated to say that no two species can occupy the same niche indefinitely when resources are limiting. Certainly species can and do coexist while competing for some of the same resources. Nevertheless, Gause’s theory predicts that when two species coexist on a long‑term basis, their niches must not be limited or their niches will always differ in one or more features; otherwise, one species will outcompete the other and the extinction of the second species will inevitably result, a process referred to as competitive exclusion.
When does the growth rate of a population following the logistic model equal zero? The logistic model is given as dN/dt=rN(1−N/K)
In logistic growth model population growth equation is described as dN/dt=rN[1−N/K]
N = population density at time t;
r = intrinsic rate of natural increase;
K = carrying capacity When N/K = 1; 1 − N/K = 0
Therefore, dN/dt=0
The term ecosystem was coined by
Sir Arthur George Tansley was an English botanist and a pioneer in the science of ecology who coined the term ecosystem.
Which of the following is a characteristic feature of cropland ecosystem?
Cropland ecosystem is the largest anthropogenic ecosystem characterized by less diversity and high productivity.
Which of the following would appear as the pioneer organisms on bare rocks?
Lichens produce small amounts of carbonic acids from their “roots” and these slowly dissolve the rock, releasing nutrients. Other nutrients are obtained from water‑borne or air‑borne particles of both organic and inorganic materials. The body of a lichen contains an alga; this is able to photosynthesize sugars, some of which are passed on to the fungal component of the lichen. In return, the alga gets a tiny but significant amount of shelter within the tissues of the lichen.
Which of the following is the most important cause of animals and plants being driven to extinction?
The primary cause of human‑induced extinction events is simply human overpopulation of planet Earth. The most important causal anthropogenic activities are habitat destruction and fragmentation.
Which is the National Aquatic Animal of India?
River Dolphin is the National Aquatic Animal of India. This mammal is also said to represent the purity of the holy Ganga as it can only survive in pure and fresh water. Platanista gangetica has a long pointed snout and also visible teeth in both the upper and lower jaws.
A river with an inflow of domestic sewage rich in organic waste may result in
Domestic sewage rich in organic waste leads to increase in Biological Oxygen Demand, which leads to decrease in D.O. (dissolved oxygen) which leads to death of fishes.
Joint Forest Management Concept was introduced in India during
Joint Forest Management originated in West Bengal accidentally at the Arabari Forest Range in West Midnapore, near Midnapore town in 1971. After the initial successes in West Bengal and Haryana, the JFM scheme received national importance in the legislation of 1988.
Depletion of which gas in the atmosphere can lead to an increased incidence of skin cancers
The ozone layer or ozone shield refers to a region of Earth’s stratosphere that absorbs most of the Sun’s ultraviolet (UV) radiation. It contains high concentrations of ozone (O₃) relative to other parts of the atmosphere.
Which of the following is not a stem modification?
Pitcher of Nepenthes is modified leaf. It helps to trap insects, in insectivorous plants.
A typical fat molecule is made up of:
A typical fat molecule is triglyceride formed by esterification of one glycerol and three fatty acid molecules. The three fatty acids can be of same type or different depending on the type of the fat molecules.
Asthma may be attributed to
Asthma is an allergic reaction characterised by spasm of bronchial muscles because of effect of histamine by mast cells.
Match the terms in Column-I with their description in Column-II and choose the correct option.
A - (ii) B-(iii) C-(iv) D(i)
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