NEET-UG 2019 Question Paper Solutions

In steady state, the amount of heat flowing from one face to the other face in time dt is given by

H = kA(T₁ − T₂)dt/l

⇒ dH/dt = kA/L × ΔT (k = coefficient of thermal conductivity)

∴ k = (L/AΔT) × (dH/dt)

Unit of k = W m⁻¹ K⁻¹.

Given, x= A²B¹ᐟ²/ C¹ᐟ³D³

% error, Δx/x × 100= 2ΔA/A × 100 + 1/2·ΔB/B × 100 + 1/3·ΔC/C × 100 + 3ΔD/D × 100

= 2 × 1% + 1/2 × 2% + 1/3 × 3% + 3 × 4%

= 2% + 1% + 1% + 12% = 16%

Velocity of swimmer w.r.t. water, V_ SR = 20 m/s

Velocity of river, V_RG = 10 m/s

sin θ = V_RG / V_SW

⇒ sin θ = 10/20

⇒ sin θ = 1/2

∴ θ = 30° west

i.e., to cross the river along the shortest path, swimmer should make his strokes 30° west.

As the three forces form a closed vector triangle in the same order, i.e., F(vector) net = 0 or m dv(vector) /dt = 0 Velocity remains constant. v(vector) = Constant

Given: Mass of block, m = 10 kg Radius of cylindrical drum, r = 1 m; Coefficient of friction, between the block and

+the inner wall of the cylinder μ = 0.1;

Minimum angular velocity ω_min

For equilibrium of the block limiting friction,

f_L ≥ mg

⇒ μN ≥ mg

⇒ μrω² ≥ mg

Here, N = mω²r

or, m ≥ √(g/μr)

or, ω_min = √(g/μr)
ω_min = √(10/0.1× 1) = 10 rad/s

Work done by variable force

m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂

Also, 1/2m₁u₁² + 1/2m₂u₂²

= 1/2m₁v₁² + 1/2m₂v₂²

For elastic collision,

v₂ = 2m₁u₁/(m₁ + m₂)

as u₂ = 0; u₁= u

m₁ = 4m and m₂= 2m

so, v₂ = 4/3u

ΔKE/KE = 1/2 × 2m × (4/3u)²

= 1/2 × 2 × 16/9 = 8/9

Let T_A and T_B are the time periods of particles A and B respectively. According to question

T_A = T_B = T

if ω_A and ω_B are their

Angular speed, then

ω_A = 2π/T_A and ω_B = 2π/T_B

ω_A/ω_B = T_B/T_A =T/T = 1 : 1

According to the Work-energy theorem,

W = 1/2 I (ω_f² − ωᵢ²)

Given that

θ = 2 π revolution/ minute

∴ θ = 2π × 2π = 4π²rad

ωᵢ = 3 × 2π/60 rad/s

ω_f = 0 rad/s

Putting the values of ωi and ωf, we get

⇒ -τθ = 1/2 × 1/2 mr² (0² − ωᵢ²)

⇒ - τ = (1/2 × 1/2 × 2 × (4×10⁻²) × (3×2π/60)² )/ 4π²

⇒ τ = 2 × 10⁻⁶ Nm

Work done to stop the disc = change in total kinetic energy of disc
Final KE = 0
Initial KE = Translational K.E. + Rotational K.E.
= 1/2 mv² + 1/2 Iω²
= 1/2 mv² + 1/2 × mR²/2 × (v/R)²
= 1/2 mv² + 1/4 mv² = 3/4 mv²
= 3/4 × 100 × (20 × 10⁻²)²n = 3J
|ΔKE| = 3J

Mass to be raised = m
Potential energy at the surface of the earth
U_surface = −GMm/R
Potential energy at a height from the surface of the earth h = R
U_height = −GMm/2R
According to work-energy theorem, work done = change in PE
∴ W = U_height − U_surface
⇒ −GMm/2R − (−GMm/R)
⇒ GMm/2R = gR²m/2R = mgR/2 (∵ GM = gR²)

Here,

Kx₀ = Mg
where K = force constant
ΔE = 1/2 Kx₀²
= 1/2 Mg/x₀ × x₀²
= 1/2 Mgx₀
Stored elastic potential energy in extended wire,= 1/2 Mgl
[here x₀ = l]

Volume flow rate of liquid
Q = au = a√2gh
= 2 × 10⁻⁶ m² × √(2 × 10 × 2) m/s
= 2 × 2 × 3.14 × 10⁻⁶ m³/s
= 12.56 × 10⁻⁶ m³/s
= 12.6 × 10⁻⁶ m³/s

Pressure inside the soap bubble

Pressure inside the soap bubble

=Pₒ +4T/R

And pressure at a point below the surface of water = pgZₒ,

+Pₒ

[where Pₒ = atmospheric pressure]

By equating these pressure we get,

Pₒ +4T /R = Pₒ + ρgZₒ

Zₒ =4T/R x ρg

Zₒ == 4 x 2.5 x 10⁻²/ 10⁻³ x 1000 x 10 m

Zₒ =1cm

l′_Cu = l_Cu(1+α_Cu ΔT)

Δl_Cu=l_Cu α_CuΔT

l′_Al=l_Al(1+α_AlΔT)

Δl_Al=l_Al α_AlΔT

Since, change in length is independent of temperature ∴  α_Cu l_Cu=α_Al l_Al

⇒1.7×10⁻⁵×88cm = 2.2×10⁻⁵×1_Al

⇒l_Al = 1.7×88/2.2 = 68cm

Using first law of thermodynamics equation,

ΔQ = ΔU + ΔW 54 × 4.18

=ΔU + 1.013 × 10⁵(167.1 × 10⁻⁶ − 0) (∵ ΔW = PΔV)

⇒ ΔU = 208.7 J

In adiabatic process, there is no exchange of heat with the surroundings.

U=F/2 nRT

As, U α T

∴ Increase in Temperature would lead to the increase in kinetic energy of gas.

At t = 0, y = 3, which is maximum displacement so equation will be cosine function.

ω = 2π/T = 2π/4 = π/2 rad/s (∵ T = 4 s)

y = a cos ωt ⇒ y = 3 cos (π/2)t

Displacement of the particle in one complete vibration is zero, so, average velocity in one complete vibration will be zero. Displacement/Time interval = y_f - yᵢ /T = 0

Given equation

y = A₀ + A sin ωt + B cos ωt

Now assume (y − A₀) = y'

y − A₀ = A sin ωt + B sin ωt

Y = A sin ωt + B cos ωt

= √(A² + B²) sin (ωt + Φ)

which is S.H.M.

where sin and cos Φ = B/√(A² + B²) so, resultant amplitude = √(A² + B²)

Electric field due to line charge (1)

E₁(vector) = λ/2πɛ₀R  îN/C

Electric field due to line charge (2)

E₂(vector) = λ/2πɛ₀R  îN/C

∴ Enet(vector) = E₁(vector) + E₂(vector)

= λ/2πɛ₀R î + λ/2πɛ₀R î

= λ/πɛ₀R î N/C

Charge Q will be distributed over the surface of hollow metal sphere. For r < R (inside the hollow sphere) [At a point inside the hollow sphere]

When all bulbs are glowing

R_eq = R/3 + R/3 = 2R/3

Power (P₁) = E²/R_eq = 3E²/2R ..........(i)

When two from section A and one from section B are glowing, then

R_eq = R/2 + R = 3R/2

Power (P_f) = 2E²/3R ..........(ii)

Dividing equation (i) by (ii) we get

P₁/P_f = (3E² × 3R)/(2R × 2E²) = 9 : 4

Resistance for ideal voltmeter = ∞

Resistance for ideal ammeter = 0

For 1st circuit

V₁ = i₁ × 10= 10/10 × 10 = 10 volt

For IInd circuit

V₂ = i₂ ×10= 10/10 × 10 = 10 volt V₁ = V₂ and, i₁ = i₂ = 10V/10Ω = 1 A

Radius of the path r = mv/qB = p/qB

For H⁺ ion, r_H = P_H/eB

For α particle,

r_α = pα/2eB

r_H/r_α =p/ eB/p/ (2eB)

[as given p_H = p_α = p]

⇒ r_H/r_α = 2/1

As we know that the angle of dip is the angle between earth’s resultant magnetic field from horizontal. At equator, dip is zero. At Northern hemisphere, dip is positive. At Southern hemisphere, dip is negative. (image pending)

Given:

Magnetic field B = 5 × 10⁻⁵ T

Number of turns in coil N = 800

Area of coil A = 0.05 m²
Time taken to rotate = Δt = 0.1 s
Initial angle θ₁ = 0°
Final angle θ₂ = 90°
Change in magnetic flux ΔΦ
= NBA cos 90° − BA cos 0°

=- NBA
= 800 × 5 × 10⁻⁵ × 0.05
= −2 × 10⁻² Weber
θ = - ΔΦ/Δt =- (−2 × 10⁻³)Wb/0.1 = 0.02 V

λ_Red > λ_Green > λ_Blue > λ_Violet

Red has the longest wavelength.

For total internal reflection when i = i_c, then

refracted ray grazes with the surface. That means the angle of refraction r = 90°.

Equivalent focal length in air

1/F₁ = 1/f + 1/f

⇒ F₁ = f/2 ...................................(i)

where glycerin is filled inside, it behaves like a concave lens of focal length (−f)

1/F₂ = 1/f + 1/(−f) + 1/f ⇒ F₂ = f ......................................(ii)

Dividing (i) by (ii), we get

F₁/F₂ = 1/2

Rainbow will be observed only when the sun is at the back side of observer.

For double slit experiment angular fringe width θ₀ = β/D Angular fringe width (in water) θ_w = β/μD = θ₀/μ = 0.2°/(4/3) = 0.15°

de-Broglie wavelength of electron

λ = 12.27/√V Å = 12.27 × 10⁻¹⁰ /√10000 = 12.27 × 10⁻¹² m

According to Bohr's model of H-atom, the relation between kinetic energy, potential energy and total energy

K.E. = |TE|= |P.E.|/2

so, K.E. = −(T.E.)

∴ K.E. = 3.4 eV

and P.E. = −(2T.E)

⇒ P.E. = −6.8 eV

α-particle is nucleus of helium He⁺⁺ which has two protons and two neutrons.

In p-type semiconductor, trivalent impurities are added to intrinsic semiconductor, which creates holes which are majority charge carriers.

From the given logic circuit, LED will glow, when voltage across LED is high.

Boolean expression Y = A̅.B̅

i.e. circuit represents NAND gate.

Given, weight of the body, w = 200 N

As we know,

w=mg, where m is the mass of the body and g (≈10 m/s²) is acceleration due to gravity of the body at the surface of the earth.

Since, mass remains constant irrespective of the position of the body on the earth. However, g is not constant and its value at a depth d below the earth's surface is given as

g' = g(1 − d/R) ...........................(i)

where, R is the radius of the earth. Multiplying on both sides of Eq. (i), we get

mg' = mg(1 − d/R)

Thus, the weight of the body at half way down

(i.e. d = R/2) to the centre of the earth is

mg' = 200 × (1 − R/2/R) = 200 (1 − 1/2) = 200 × 1/2 = 100

∴ The body will weight 100 N half way down to the centre of the earth.

Among given devices fuse is used in electric circuit as a protective device. It helps in preventing excessive amount of current to flow in the circuit or from short circuiting. It has low melting point and low resistivity, so when excess amount of current flow in the circuit, it melts and break the circuit.

Given, C = 20 μF = 20 × 10⁻⁶ F dV/dt = 3 V/s

The displacement current in a circuit is given by

I_d = ε₀ dϕ/dt [from Maxwell's equation]

= ε₀ d/dt (EA) [∵ ϕ = EA]

= ε₀A d/dt (V/d) [∵ V = Ed]

= (ε₀A/d) dV/dt

As the capacitance, C = ε₀A/d

I_ d = C dV/dt

Substituting the given values, we get

I_d = 20 × 10⁻⁶ × 3 = 60 × 10⁻⁶ A = 60 μA

The motion of object shot in two cases can be depicted as below Using third equation of motion,

v² = u² − 2gh ............ (i)

As the object stops finally, so

v = 0

For inclined motion,

g = g sin θ and h = x

Substituting these values in Eq. (i), we get

u² = 2g sin θ x ⇒ x = u²/(2g sin θ)

For case (I), x₁ = u²/(2g sin 60°)

For case (II), x₂ = u²/(2g sin 30°)

x₁/x₂ = u²/(2g sin 60°) × 2g sin 30°/u²

= 1/2 × 2/√3 = 1/√3 or 1 : √3

N₂ + 3H₂ ⟶ 2NH₃

1 mol NH₃ = 3/2 mol H₂

20 mol NH₃ = 3/2 × 20 mol H₂ = 30 mol H₂

∴ 30 moles of H₂ are required.

Balmer series

5f 5 + 3 = 8
6p 6 + 1 = 7
5p 5 + 1 = 6
4d 4 + 2 = 6
∴ 5f > 6p > 5p > 4d

Consider the stability of electronic configuration after loss of one electron.

Consider the stability of electronic configuration after loss of one electron.

Only π bond is present in C₂ molecule.
σ1s² σ*1s² σ2s² σ*2s² π2px² π2py²

Compressibility factor,
Z = PV/nRT
Given: At 350 K and 15 bar,
molar volume of ideal gas
∴ Z < 1
Therefore, attractive forces are dominant and the gas can be compressed easily.

W = −P_ext (V₂ − V₁) (Irreversible isothermal expansion)
= −2(0.25 − 0.1)
= −2(0.15)=0.3 L Bar
= −0.3 × 100 J = −30 J

In 2H(g) → H₂(g), no. of moles decreases, therefore entropy decreases.

When a proton is removed from an acid, we obtain its conjugate base.
H₂O ⇌ H⁺ + OH⁻
HF ⇌ H⁺ + F⁻

Ca(OH)₂ ⇌ Ca²⁺ + 2OH⁻
(pH = 9, pOH = 14 − 9 = 5)
[OH⁻] = 10⁻⁵
[Ca²⁺] = 10⁻⁵/2
Kₛₚ = [Ca²⁺][OH⁻]₂
= (10⁻⁵/2) × (10⁻⁵)²
= 0.5 × 10⁻¹⁵

In a disproportionation reaction, one species undergoes both oxidation and reduction.

In this method Ca(OH)₂ is used.

Amphoteric hydroxide means it can react with both acid and base.
Be(OH)₂ + 2HCl → BeCl₂ + 2H₂O
Be(OH)₂ + 2NaOH → Na₂[Be(OH)₄]

Enzyme that utilise ATP in phosphate transfer require an alkaline earth metal (M) Mg as the cofactor.

PbF₄ is ionic in nature due to high electronegativity difference.

[SiCl₆]²⁻ does not exist because six large chloride ions cannot be accommodated around Si⁴⁺, due to its small size.

Alkynes can be reduced to cis-alkenes with they of Lindlar’s catalyst

Sulphur dioxide is not a greenhouse gas.

Oh void(C) : HCP(A)

No. of ions ⇒ 6 × 75/100 : 6

3/4 : 1

3 : 4 C₃A₄

Hydrogen bond of ethanol gets weakened by addition of acetone. Thus the mixture of ethanol and acetone shows positive deviation from Raoult's law.

The solutions which show a large negative deviation from Raoult's law form maximum boiling azeotrope. Nitric acid and water forms a maximum boiling azeotrope with a boiling point of 393.5 K.

E°_cell = (2.303RT/nF) log K
Given: E°_cell = 0.59 V, n = 1
0.59 = 0.059/1 log K
0.59/0.059 = log K
10 = log K
K = 10¹⁰

ΔG° = −nFE°
= −2 × 96500 × 0.24 = −46320 J/mol
= −46.32 kJ/mol

For a first order reaction,
t = (2.303/k) log ([A]₀/[A])
For 99% completion of the reaction,
t = (2.303/k) log (100/100 − 99)
= (2.303/k) log 10²
= 4.606/k

N₂(g) + 3H₂(g) ⇌ 2NH₃(g)
−d[N₂]/dt = −1/3 d[H₂]/dt = 1/2 d[NH₃]/dt

AgNO₃ + KI ⟶ AgI + KNO₃
Negatively

charged colloid
A solution of AgNO₃ and KI will form a negatively charged colloidal sol [AgI], only when KI is present in excess.
(i.e., KI behaves as a solvent).
Millimole of KI is maximum in option = (50 × 2 = 100)

Malachite is a green copper carbonate hydroxide mineral with chemical composition CuCO₃.Cu₄(OH)₂.

On going down the group, bond dissociation enthalpy of the hydrides of oxygen family decreases. Therefore, thermal stability also decreases.

Option (d) is correct option.

PCl₅ is very reactive due to the presence of weak axial bonds. It is used in the synthesis of various compounds.

K₄[Fe(CN)₆]⁴⁻ ⇌ 4K⁺ + [Fe(CN)₆]⁴⁻
x = 6 − 4
x = +2
Fe: 4s² 3d⁶
Fe²⁺ : 3d⁶

Account for the inductive effect, solvation effect (H-bonding) and steric hindrance for basic character in aqueous solutions
(CH₃)₂NH > CH₃NH₂ > (CH₃)₃N

Alanine is non-essential amino acid.

nylon 2–nylon 6

penicillin G

Ideal solutions are those which obey Raoult's law over all concentration ranges at a given temperature, e.g., benzene–toluene,
n-hexane–heptane, etc.

For an ideal solution,

ΔV_mix = 0, ΔH_mix = 0

ΔG_mix = 0, ΔS_mix = 0

.

Single bond = 1σ
Double bond = 1σ + 1π
Triple bond = 1σ + 2π
The structure of pent-2-en-4-yne is
∴ The number of sigma (σ) bonds are 0 and pi (π) bonds are (d).

The given xenon compounds with its structures are as follows:

Hence, the correct match is
(A) → (ii), (B) → (iii), (C) → (iv), (D) → (i)

According to rules of binomial nomenclature, correctly written scientific name of mango is Mangifera indica Linn.
This system of nomenclature was given by Carl Linnaeus. The scientific name of mango is given as Mangifera indica Linn. Mangifera indicates the ‘genus’ while indica represents a particular species or specific epithet and Linn indicates the Biologist Linnaeus who first described the species of mango.

The keys are based on the set of contrasting characters in pair known as couplet.

Azotobacter is aerobic bacteria. and Cladophora is green alga.

Engelmann used a prism to split light into its spectral components, and then illuminated a green alga, Cladophora,

placed in a suspension of aerobic bacteria. The bacteria were used to detect the sites of oxygen evolution. He observed that aerobic bacteria accumulated mainly in

the region of blue and red light of the split spectrum thus giving the first action spectrum of photosynthesis.

Halophiles live in salty areas.
Thermoacidophile are present in hot springs. Methanogens are present in gut of several ruminants. Cyanobacteria can be present in freshwater/marine or terrestrial habitat.

Yeast is an unicellular sac fungi. It lacks filamentous structure or hyphae.

Infective constituent in viruses is either DNA or RNA, not protein. The simplest form consist of two basic components: nucleic acid (single- or double-stranded RNA or DNA) and a protein coat, the capsid, which functions as a shell to protect the viral genome from nucleases and which during infection attaches the virion to specific receptors exposed on the prospective host cell.

Prions are disease causing agents having abnormally folded proteins. Prions induce other healthy proteins to fold incorrectly, leaving particle of useless debris and holes that turn brains to sponge, resulting to death. This disease has an incubation period in cattle of up to eight years.

Fungus associated with roots of Pinus increases minerals and water absorption for the plant by increasing surface area and in return fungus gets food from plant. Therefore, mycorrhizal association is obligatory for Pinus seed germination.

Phloem, a complex tissue, is found in highly organised plants ('higher plants') and characterised by the possession of certain specialised cells, the sieve elements, and functions as the major plant tissue in rapid conduction of sugar over fairly long distances in the plant. In addition to sieve elements, it always contains parenchyma cells, usually of more than one type, and frequently includes sclerenchyma cells.
Phloem in gymnosperms lacks both sieve tube and companion cells.

Annelids exhibit bilateral symmetry with metameric

segmentation where external segments correspond to

Adult echinoderms are bilaterally symmetrical

Aschelminthes are pseudocoelomates and platyhelminthes

are acoelomates.

Organ system of organisation, bilateral symmetry true coelomates with segmented body are found in annelig

arthropoda and chordates.

In Mollusca, the body is unsegmented.

(A) Pila is a member of mollusc. The mouth contains a rasping organ for feeding called radula.

(B) Bombyx is an arthropod. In Bombyx excretion takes place through malpighian tubules.

(C) Pleurobrachia is a ctenophore. The body bears eight external rows of ciliated comb plates, which help locomotion.

(D) Taenia is a platyhelminth, In it specialised cells, called flame cells are present which help in osmoregulation

and excretion,

Intercalary Meristem.

The grass stem regenerates after initial growth due to intercalary meristem because this meristem helps in

regeneration of parts in grasses removed in grazing herbivores.

Xylem is a type of complex tissue. It translocates water, mineral salts, organic nitrogen and hormones.

Growth rings are formed by the seasonal activity of cambium. In plants of temperate regions, cambium is more active in spring (less lignin deposition in xylem) and

less active in autumn (more lignin deposition in xylem) seasons. In temperate regions climatic conditions are not

uniform throughout the year. However in tropics climatic conditions are uniform throughout the year.

Tight junctions provide a barrier which prevents leakage of fluid across epithelial cells.
Adherens junctions aid to cement adjacent cells to form a sheet.
Gap junctions provide cytoplasmic channels to facilitate communication between adjacent cells.
Synaptic junctions help in transmission of information through chemicals.

Cockroaches receive several images of an object with the help of ommatidia. This kind of vision possessed by cockroaches is known as mosaic vision which has more

sensitivity but less resolution.

The organism which have ribosomes of 70 S type are prokaryotes. Prokaryotes have double stranded DNA which is not enclosed in membrane.

The important function of Golgi apparatus is to process, package and transport the materials for secretion. Therefore secretory cells have Golgi apparatus in highest number.

Golgi apparatus is involved in the formation of glycoproteins and glycolipids.
Lysosomes are membrane enclosed organelle. It contains digestive enzymes, which digest excess or worn out organelles, food particles etc.
Vacuoles is a membrane enclosed fluid filled sac which traps waste and excretory products.
Ribosomes is a minute particle consisting of RNA and associated proteins. They bind mRNA and tRNA to synthesise polypeptides and proteins.

Concanavalin A is a secondary metabolite, e.g. lectin. Lectin is a mannose/glucose binding protein isolated from Jack beans (Canavalia ensiformis). They are not antibodies and do not originate in an immune system but bind specifically to carbohydrate-containing receptors on cell surfaces (as of red blood cells).

Purines, a heterocyclic compounds, such as adenine and guanine are found both in DNA and RNA.

GLUT1 and GLUT11 are glucose transport proteins which facilitate glucose transport into insulin sensitive cells. GLUT1 is insulin-independent and is widely distributed in different tissues. GLUTIV is insulin-dependent and is responsible for the majority of glucose transport into muscle and adipose cells in anabolic condition.

Coenzyme or metal ion that is tightly bound to enzyme protein is called prosthetic group. A complete catalytic active enzyme with its bound prosthetic group is called holoenzyme.
A protein that forms an active enzyme system by combination with a coenzyme and determines the specificity of this system for a substrate is called apoenzyme.

G₀ or resting phase is a non-growing state distinct from interphase. It is a period in the cell cycle in which cells exist in a quiescent state. It is viewed as either an extended G₁ phase, where the cell is neither dividing nor preparing to divide, or a distinct quiescent stage that occurs outside of the cell cycle.

Cell cycle is the complete series of events from one cell division to the next. The correct sequence of phases of cell cycle is:
G₁ → S → G₂ → M

Active transport is uphill transport. This transport takes place against the electrochemical potential gradient and requires additional input of energy that chiefly comes from hydrolysis of ATP. It is highly selective.

When a plant cell is placed in hypotonic solution water will flow into the cell as water moves from high water potential to low water potential.

Inactive transport, materials are transported across a membrane with the help of mobile carrier protein and ATP.

In passive transport, substances move along the concentration gradient, i.e., from its higher concentration to its lower concentration.

The direction of movement of sugar in phloem is bi-directional.
The Pressure Flow Hypothesis, also known as the Mass Flow Hypothesis, is the best-supported theory to explain the movement of sap through the phloem. It was proposed by Ernst Munch, a German plant physiologist in 1930. A high concentration of organic substances, particularly sugar, inside cells of the phloem at a source, such as a leaf, creates a diffusion gradient (osmotic gradient) that draws water into the cells from the adjacent xylem. This creates turgor pressure, also known as hydrostatic pressure, in the phloem. Movement of phloem sap occurs by bulk flow (mass flow) from sugar sources to sugar sinks. The movement is induced in is bidirectional, whereas, in xylem cells, it is unidirectional (upward). Because of this multidirectional flow, coupled with the fact sap cannot move with ease between adjacent sieve-tubes, it is not unusual for sap in adjacent sieve-tubes to be flowing in opposite directions.

Bulliform cells are large, bubble-shaped epidermal cells that occur in groups on the upper surface of the leaves of many grasses. These cells become flaccid due to water loss. Loss of turgor pressure in these cells causes leaves to "roll up" during water stress.

Thiobacillus denitrificans, a type of denitrifiers, converts nitrates in soil to free atmospheric nitrogen, thus depleting soil fertility and reducing agricultural productivity.

Thiobacillus denitrificans cause denitrification i.e., conversion of oxides of nitrogen to free N₂.

Hatch and Slack pathway is a cyclic pathway for CO₂ fixation. The primary CO₂ acceptor is a 3-carbon compound phosphoenol pyruvate (PEP) which is present in mesophyll cells.
PEP is converted to oxaloacetic acid (OAA), which is then further converted into a 4-carbon compound such as malic acid or aspartic acid, which is then transported to the bundle sheath cells. In the bundle sheath cells, it is again broken down into a 3-carbon compound with the release of CO₂. The CO₂ released enters the Calvin cycle in the bundle sheath cells, while the 3-carbon compound is transported back to the mesophyll cells. In the mesophyll cells, the 3-carbon compound is converted back to PEP, thus completing the cycle.

Glycolysis is the anaerobic enzymatic conversion of glucose to lactate or pyruvate, resulting in energy stored in the form of ATP, as occurs in muscle.
The two irreversible steps in Glycolysis are:
(i) Conversion of glucose to glucose 6-phosphate, catalysed by hexokinase. It is the first step of activation phase of glycolysis.
(ii) Conversion of fructose 6-phosphate to fructose 1,6 bisphosphate catalysed by phosphofructokinase-1.

Electron transport system is located in inner mitochondrial membrane, where it serves as the site of oxidative phosphorylation through the action of ATP Synthase.

Respiratory quotient may be defined as a ratio indicating the relation of the volume of carbon dioxide given off in respiration to that of the oxygen consumed.
Respiratory Quotient

Auxin shows apical dominance. Removal of auxin by removal of shoot tips prevents the apical dominance and promotes the growth of lateral buds which is a useful in tea leaves production.

Gibberellins (GAs) regulate various developmental processes, including stem elongation, germination, dormancy, flowering, flower development and leaf and fruit senescence. When gibberellin is sprayed on sugarcane crop, the length of the stem increases.

A pineapple plant flowers only once, and produces one pineapple. Then it dies. But before it dies it also reproduces by offsprings.
Auxin and ethylene can be applied to artificially induce flowering in pineapple to increase yield throughout the year. Auxin applied to pineapple is converted into ethylene, not stimulating ethylene formation, and that ethylene, not auxin, causes pineapples to flower. Ethylene initiates flowering and synchronising fruit-set in pineapples.

During flowering, photoperiodic stimulus is perceived by leaves of plants.

Rennin is a milk digesting proteolytic enzyme related to pepsin that is synthesised by chief cells in the stomach of some animals.
Enterokinase, produced by cells of duodenum, is involved in it. It converts trypsinogen (a zymogen) into its active form trypsin, resulting in the subsequent activation of pancreatic digestive enzymes.
Fructose shows facilitated transport.
Oxyntic cells secrete HCl and intrinsic factors that are essential for absorption of vitamin B₁₂.

Goblet cells secrete mucus. It is secreted along entire digestive tract where it lubricates food and lining, coats lining and protects it from mechanical digestion, from acid and digestive enzymes.

Crypts of Lieberkuhn are tubular glands that lie between the finger-like projections of the inner surface of the small intestine. Glisson's capsule is a layer of connective tissue present in liver. Islets of langerhans constitute the endocrine portion of pancreas and are responsible for the production and release of hormones that regulate glucose levels. Brunner's glands are found in submucosa of duodenum and protect the intestinal walls from gastric juices.

Expiratory capacity is the total volume of air that a person can expire after a normal inspiration. This includes tidal volume and expiratory reserve volume.
Expiratory capacity = TV + ERV
Tidal volume of an athlete = 500 mL
Expiratory reserve volume of an athlete = 1000 mL
Expiratory capacity = TV + ERV
= 500 + 1000
= 1500 mL

Asthma (an allergic condition) is a difficulty in breathing causing wheezing due to inflammation of bronchi and bronchioles. It can be due to increasing air borne allergens and pollutants. Many people in urban areas are suffering from this respiratory disorder.

SA node acts as pace-maker because it is autoexcitable tissue have the ability to generate impulses at highest rate (frequency).

The delay in transmission of impulse from SAN to the ventricles provided by AVN prevents simultaneous contraction of ventricles and auricles. This allows atria to empty completely before ventricles start contracting.

Electrocardiogram is a diagnostic tool, used to assess electrical and muscular functions of the heart. It consists of waveforms which represent electrical events during one heartbeat. These waveforms are labelled P, Q, R, S, T and U.
P wave indicates atrial depolarisation i.e. that the atria are contracting, pumping blood into the ventricles.
The QRS complex represents ventricular depolarisation and contraction.
T wave is upwards waveform representing ventricular repolarisation. The normal T wave is slightly asymmetrical with a steeper downward slope. Reduction in the size of T wave represents insufficient supply of oxygen, i.e. coronary ischemia. Coronary ischemia is an intermediate condition in coronary artery disease during which the heart tissue is slowly or suddenly starved of oxygen and other nutrients.

Cardiac output is the product of the heart rate (HR), or the number of heart beats per minute (bpm), and the stroke volume (SV), which is the volume of blood pumped from the ventricle per beat; thus,
Cardiac output = Stroke volume × Heart rate
As per the given info,
Cardiac output = 5L or 5000 mL
Blood volume in ventricles at the end of diastole = 100 mL
Blood volume in ventricles at the end of systole = 50 mL
Stroke volume = 100 − 50
= 50 mL
So,
5000 = 50 mL × Heart rate
Heart rate = 100 beats per minute.

Loop of Henle along with vasa recta plays an important role in the concentration of urine. The proximity between loop of Henle and vasa recta as well as counter current in them help in maintaining an increasing osmolarity towards the inner medullary interstitium. This mechanism helps to maintain a concentration gradient in medullary interstitium so human urine is nearly four times concentrated than initial filtrate formed. The urine concentrating mechanism plays a fundamental role in regulating water and sodium excretion.

Statements (iii) and (iv) are correct.
Dialysis is a procedure that is a substitute for many of the normal functions of the kidney.
(a) It remove waste, salt and extra water to prevent them from building up in the body.
(b) It keep a safe level of certain chemicals in your blood, such as potassium, sodium and bicarbonate helping to control blood pressure.
(c) The will be reduced absorption of calcium ions from gastrointestinal tract.
(d) RBC production will be reduced, due to reduced erythropoietin hormone.

There are 12 pairs of ribs in human body. First seven pairs are attached to the sternum ventrally with the help of hyaline cartilage, also called as true ribs. These are called vertebrosternal ribs. The next three pairs (8th, 9th and 10th) do not articulate directly with the sternum, also called vertebrochondral (false) ribs. The last two pairs (11th and 12th) are the free floating ribs because they are not connected ventrally.

Muscular dystrophy is an inheritable disease that gradually cause the muscles to weaken, leading to an increasing level of disability.
Tetany, Myasthenia gravis and Botulism are not inheritable diseases.

Rods and cones are two types of photoreceptor in human retina. Cones are very sensitive to operate in day light. They are capable of colour vision and responsible for high spatial acuity. Rods are very sensitive in dim light and do not mediate colour vision and have a low spatial acuity.

Insulin is a pancreatic hormone, secreted from alpha cells of islets of Langerhans. Its deficiency leads to diabetes mellitus (characterised by high blood sugar levels over a prolonged period).
Thyroxine is an iodine containing hormone, secreted by the thyroid gland. It plays an important role in regulating the body's metabolic rate, heart and digestive function, muscle control, brain development and bone maintenance. Hyper secretion or hyposecretion of thyroxine can be associated with enlargement of thyroid gland called goitre.
Deficiency of corticoids (cortisol and aldosterone) secreted from adrenal gland (cortex region) leads to Addison's disease. Cortisol regulates the body's reaction to stressful situations. Aldosterone helps with sodium and potassium balance. The adrenal cortex also produces sex hormones (androgens).
Acromegaly is an abnormal growth of the hands, feet, and face, caused by overproduction of growth hormone by the pituitary gland.

The phenomenon in which female gamete develops into embryo without getting fused with male gamete (fertilisation) is called parthenogenesis.
Autogamy is a form of self-fertilisation in which fission of the cell nucleus occurs without division of the cell, the two pronuclei so formed reuniting to form the synkaryon.
Parthenocarpy is the production of fruit without fertilisation.
Syngamy is a nucleus formed by the fusion of the two pre-existing nuclei.

In flowering plants, out of the two male gametes discharged in synergids, one fuses with the egg and other fuses with the secondary nucleus present in the central cell.
Egg (n) + 1st male gamete (n) → Zygote (2n)
Secondary nucleus (2n) + 2nd male gamete (n) → Endosperm nucleus (3n)
(central cell nuclei)

Post-fertilisation is a series of events that take place after fertilisation. Following are the post-fertilisation changes in flowering plants.
• Ovule → Seed
• Ovary → Fruit
• Zygote → Embryo
• Central cell → Endosperm

In some seeds like black pepper and beet, the remnants of nucellus are persistent, this persistent nucellus is called perisperm. It is present in the seeds in the form of a layer of nutritive tissue.

Extrusion of second polar body from egg nucleus occurs after entry of sperm into the secondary oocyte but before fertilisation. The entry of sperm into the ovum is accomplished by sperm mediated division of the secondary oocyte. Entry of sperm causes breakdown of metaphase promoting factor (MPF) and turns on anaphase promoting complex (APC).

The correct sequence for transport of sperm cells in male reproductive system is:
Seminiferous tubules → Rete testis → Vasa efferentia → Epididymis → Vas deferens → Ejaculatory duct → Urethra → Urethral meatus

In lactational amenorrhea pills and emergency contraceptives methods, there is the involvement of Lactational amenorrhea (absence of menstruation) is based on the fact that ovulation and intense lactation following parturition. Prolactin is the major hormone responsible for milk production and is present in sufficient quantities in almost all women to allow the establishment of normal lactation.
Emergency contraception methods include emergency contraception pills (ECP), intrauterine device, e.g. LNG-20 (Levonorgestrel) and ulipristal acetate.
CuT and barrier method do not involve any hormonal role.

Progesterone and LNG-20 are hormone releasing IUDs (Intra Uterine Devices). These are the devices which are used in birth control by making uterus unsuitable for implantation and the cervix hostile to sperms.

Genital herpes is caused by two types of viruses—herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2). At present there is no cure for type-II-herpes simplex virus. Other non curable STIs are hepatitis-B and HIV.

Genes for flower colour in snapdragon shows incomplete dominance which is an exception of Mendel's law.

first principle (i.e. Law of dominance), whereas Law of segregation is universally applicable. Incomplete dominance is a process when a dominant allele, or form of a gene, does not completely mask the effects of a recessive allele, and the organism's resulting physical appearance shows a blending of both alleles.

1 map unit represent 1% cross over. Map unit is used to measure genetic distance. This genetic distance is based on average number of cross over frequency.

In birds female heterogamety is found thus sex of progeny depends on the types of egg rather than the type of sperms of birds (fowls).

There will be no change in reading frame of m-RNA by deletion of GGU from 7th, 8th and 9th position.

Expressed Sequence Tags (ESTs) are DNA sequences (genes) that are expressed as mRNA for protein synthesis. These are used in Human Genome Project.

Lac operon consist of one regulatory genes (i gene) and three structural genes (z, y and a).
• i gene codes for Repressor.
• z gene codes for Beta-galactosidase.
• y gene codes for Permease.
• a gene codes for Transacetylase.

Adaptive radiation occurs when a single or small group of ancestral species rapidly diversifies into a large number of descendant species. Therefore, when a
population of a species invades a new area with many type of vacant habitats, they face different environmental
pressures and eventually adapt exhibiting adaptive radiation.

In Australia, marsupials and placental mammals have evolved to share many similar characteristics. This type of evolution may be referred to as convergent evolution.

Stabilising selection is a type of natural selection in which the population mean stabilises on a particular non- extreme trait value. This is thought to be the most common mechanism of action for natural selection because most traits do not appear to change drastically over time. The result of stabilising is the over-representation in a specific trait. For example, human birth weight, the number of eggs a bird lays, and the density of cactus spines.

The given lab shows stabilising selection as most of the newborn having average weight between 3 to 3.3 kg survival and babies with less and more weight have low survival rate.

Agriculture came around 10,000 years back and human settlements started.

The Dryopithecus and Ramapithecus primates existing 15 mya. They are hairy and walked like gorillas and chimpanzees.

Homo habilis probably did not eat meat. They were the first to make stone tools.

Frequency of dominant allele (p) = 0.4
Frequency of recessive allele (q) = 1 − 0.4 = 0.6
Frequency of homozygous dominant individuals (AA)
= p² = (0.4)² = 0.16(AA)
Frequency of heterozygous individuals (Aa)
= 2pq = 2(0.4)(0.6) = 0.48(Aa)
Frequency of homozygous recessive individuals (aa)
= q² = (0.6)² = 0.36(aa)

The correct match of the hominids and their brain sizes are:
Homo habilis – 650 – 800 c.c.
Homo neanderthalensis – 1400 c.c.
Homo erectus – 900 c.c.
Homo sapiens – 1350 c.c.

According to Hugo de Vries, mutations are random and directionless.
Hugo de Vries believed that mutation caused speciation and hence called it saltation (single step large mutation).

Typhoid is a bacterial infection that can lead to a high fever, diarrhoea, and vomiting. It is caused by the bacteria Salmonella typhimurium (S. typhi).

Colostrum, as a thin yellowish milk, is the first secretion for a few days after childbirth. Colostrum serves as an immune system enhancer to the new born infants. It contains immune cells, high protein and protective antibody (such as IgA) content. IgA help protect the mucous membranes in the throat, lungs, and intestines of the infant.

Inbreeding depression, the reduction of fitness caused by inbreeding, is a universal phenomenon that depends
on past mutation, selection, and genetic drift. Inbreeding depression can be overcome by the following ways:
• Out breeding: The breeding of animals which are unrelated to each other and do not have come ancestors for 4-6 generations.
• Out crossing: Mating done with the animals of same breed but after 4-6 generations.
• Cross breeding: Superior male mated with superior female of another breed.
• Interspecific hybridisations: Male and female animal of two different related species.

Inbreeding exposes harmful recessive genes that are eliminated by selection. It also helps in accumulation of superior genes and elimination of less desirable genes. Therefore this is selection at each step & which increase the productivity of inbred population. Close and continued inbreeding usually reduces fertility and even productivity.

Saprophytes are organisms which live on dead organic matter and help in the decomposition. Parasite is an organisms that live in or on other living plants and animals and dependent on them for their food. Lichens represent a type of symbiotic association of algae and fungi, in which, both of them dependent on each other for their food and shelter.
Mycorrhiza is also a type of symbiotic association of fungi and plant roots, e.g., Cycas coralloid root.

Microbes are used in production of several household and industrial products –
• Lactobacillus – Production of curd
• Saccharomyces cerevisiae – Bread making
• Aspergillus niger – Citric acid production
• Acetobacter aceti – Acetic acid production

Statins are drugs that can lower blood cholesterol. It is obtained from a yeast (Fungi) called Monascus purpureus.
They work by blocking a substance, body needs to make cholesterol.

Biocontrol agents are those natural organisms like parasition, predation and other mechanisms which play a
important role in controlling the plant pests like nematode, weeds, insects, and mites and helps in maintaining and
balancing the plant species along with their natural enemies. Fungi Trichoderma, Baculoviruses (NPV) and
Bacillus thuringiensis are used as biocontrol agents. Rhizobium, Nostoc, Azospirillum and Oscillatoria as biostimulents, whereas TMV is a pathogen and aphids are pests that harm crops.
The most common species of fungi used in this type of biocontrol is Trichoderma harzianum.

Trichoderma is a very effective biological mean for plant disease management especially the soil born. It is a free-living fungus which is common in soil
and root ecosystems. It reduces growth, survival or infections caused by pathogens by different mechanisms like competition, antibiosis, mycoparasitism, hyphal interactions, and enzyme secretion.

To produce enzyme in large quantity, equipment requires use bioreactors. Large scale production involves use of bioreactors.

Note: In 1990, Anderson and Schwarz licensed patents for the rotating wall bioreactor technology and founded
Synthecon Inc. in Houston, Texas, to commercialize the device.

A restriction enzyme or restriction endonuclease is an enzyme that cleaves DNA into fragments at or near specific recognition sites within molecules known
as restriction sites. Restriction enzymes are one class of the broader endonuclease group of enzymes. Each
restriction endonuclease functions by inspecting the length of a DNA sequence. Once it finds its specific
recognition sequence, it will bind to the DNA and cut each of the two strands of the double helix at specific points in their sugar phosphate backbone. These enzymes predictably cut both strands because the sequences they recognize are palindromic. That is the recognition
sequences of identical bases on both DNA strands.

During the isolation of desired gene, chilled ethanol is used for the precipitation of DNA. Ethanol is used in DNA extraction to force the DNA to precipitate in a solution. In order to collect a DNA sample, cells are broken down through agitation, and then mixed with water, salt and ethanol to create an aqueous solution. Ethanol along
with salt work to prevent the DNA from dissolving into the water, instead causing it to precipitate out so it can be separated and extracted using a centrifuge.

Inside (d < R)
Magnetic field inside conductor
B = Kd ...... (i)
This is straight line passing through origin
At surface (d = R)
B= μ₀/ 2π.1/ d
Maximum at surface
Outside (d > R)
B= μ₀/ 2π .1/d
or B ∝ 1/d ∴ Hyperbolic

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