NEET-UG 2019 Question Paper — Set 2 Solutions

n VSD = (n−1) MSD
1 VSD = (n−1)/n MSD
L.C. = 1 MSD − 1 VSD = 1 MSD − (n−1)/n MSD
= 1/n MSD = 1/n × 1/n = 1/n²

As t₁ = x/v₁ and t₂ = x/v₂
∴ v = (x + x)/(t₁ + t₂) = 2x/(x/v₁ + x/v₂) = 2v₁v₂/(v₁ + v₂)
∴ 2/v = 1/v₁ + 1/v₂

Since body does not move hence it is in equilibrium.
fᵣ = frictional force which is less than or equal to limiting friction.
Now N = mg
Hence 𝐅⃗ = 𝐍⃗ + 𝐟⃗ᵣ
|𝐅⃗| = √((mg)² + (μmg)²)
|𝐅⃗| ≤ mg √(1 + μ²)

Using work-energy theorem, ΔK = work = area under

F − x graph
From x = 0 to x = 8 m
1/2mv² = 100 + 30
∴ v = √520 = 23 m/s
From x = 0 to x = 12 m
1/2mv² = 100 + 30 − 47.5 + 20
∴ v = √410 = 20.6 m/s

𝐏⃗ᵢ = 𝐏⃗f
m𝐯⃗₁ = (m/6 𝐯⃗₁ + 5m/6 𝐯⃗₂)
𝐯⃗₁= ( 𝐯⃗₁ / 6 + 5/6 𝐯⃗₂
20î + 25ĵ − 12k̂ = (100î + 35ĵ + 8k̂)/6 + 5𝐯⃗₂ /6
𝐯⃗₂ = 20î + 115ĵ − 80k̂
∴ 𝐯⃗₂ = 4î + 23ĵ − 16k̂

Bullets collide at time t
x₁ + x₂ = 100 m
25t + 25t = 100
t = 2 s
y = ½gt² = ½ × 10 × 2² = 20 m
h = 200 − 20 = 180 m

From conservation of linear momentum.
0 = mvĵ₁ + mvî₁ + 3m𝐯⃗₁
𝐯⃗₁ = −v/3 (î + ĵ)
v₁ = √2/3(v)
K_f = 1/2mv² + 1/2mv² + 1/2(3m)(√2/3)² ( v)²
= mv² + mv²/3 = 4/3 mv²
ΔKE = K_f − K_i = 4/3 mv²

v² = u² + 2as
V₀² = 0 + 2rα(2πr)n ⇒ α = V₀²/4πnr²

Kinetic energy at the bottom
= 1/2mv₀² + 1/2Iω² = 3/4mv₀²
As I_(solid cylinder) = 1/2MR² and V = Rω
From work–energy theorem
3/4mv₀² = mgh = mgd sinθ

d= 3/4mv₀² / mgsinθ

⇒ d = 3/4 v₀² /gsinθ =3/4.16/ 10×1/2 = 2.4 m

As U = −GMm/r

∴ (P.E.)_A = −GMm/R, (P.E.)_B = −GMm/R + h
∴ ΔU = (P.E.)_B − (P.E.)_A
= −GMm/R + h + GMm/R = GMmh/(R) (R + h)

T² ∝ r³

T² ∝ (R_E+ h)³
T₁²/T₂² = (R_E + 6R_E)³/(R_E + 2.5R_E)³
T₁²/T₂² = 7³/(7/2)³
T₂ = 6√2 h

Fracture point and ultimate strength point is close for material X, hence X is brittle in nature and both points are far apart for material Y hence it is ductile.

Pressure at A = Pressure at B.
Pₐ + 0.15 × 10³ × g = Pₐ + 0.20 × d₀ × g
d₀ = 0.15 × 10³ / 0.20 = 0.75 × 10³ = 750 kg/m³

Terminal velocity V_T= (ρ-σ)g
V_T₁ = 2 × (1)²/9η (ρ₁ − 0.1ρ₂)g
V_T₁ = 2 × 1/ 9η (8ρ₂ − 0.1ρ₂)g
V_T₂ = 2 × (2)²/9η (ρ₂ − 0.1ρ₂)g
∴ VT₁/VT₂ = 7.9/[4(0.9)] = 79/36

We assume that at any instant thickness of ice is x.
And time taken to form additional thickness (dx) is dt.

mL = KA(26−0)dt/x
⇒ (Adx)ρL = KA(26)dt/ x

So, dx/dt= 26K/xρL

According to Newton’s law of cooling
(T₁ − T₂)/t = K [ (T₁ + T₂)/2 − T₀ ]
(80−70)/12 = K(75−25) ...(i)
(70−60)/ t′ = K(65−25) ...(ii)
⇒ t′ = 12 × 50/40 = 15 min

ΔQ = 2256 × 1 = 2256 J
ΔW = P[V_steam − V_water] [∵ dw = pdv]
= 1 × 105 [1671 − 1] × 106 = 167 J
As ΔQ = ΔU + ΔW
2256 = ΔU + 167
ΔU = 2089 J

For Hydrogen f = 5
For Helium f = 3
For gas X
f = 7.
γ = 1 + 2/f = 1 + 2/7=9/7

So, (7/5, 5/3, 9/7)

In one time period total distance travelled by the particle is 4A.

Tsinθ) = ma
Tcosθ = mg

tan θ=a/g

θ = tan⁻¹(a/g)

At surface of earth time taken in falling h distance.

t=√2h/g

and T= 2π√l/g

Given t=2T

t/T=2

For surface of other planet

g'=g/2

Time taken in falling h distance

t' = √2h/g'=√2t

and T'= 2π√l/g'= √2T

Here t'/T'= √2t/√2T=2

t'=2T

l₁ = 9.75 cm
l₂ = 31.25 cm
l₃ = 52.75 cm
e = end correction
λ/4 + e = 9.75 cm ...(i)
3λ/4+ e = 31.25 cm ...(ii)
3λ/4- λ/4= 31.25 − 9.75
λ/2 = 21.5
λ = 43 cm
v = λ × f
= 34400 × 100 × 10⁻²
∴ v = 344 ms⁻¹

Q₁ = σ4πR₁ ² = σ4πR²
Q₂ = σ4π(2R)² = σ16πR²
After redistribution
Q₁/Q₂ = R/2R ⇒ Q'₂ = 2Q′₁ ........(i)

Q₁ + Q₂ = 20σπR² ....................(ii)
From eq. (i) and (ii)
Q'₁= 20/3σπR² ⇒ σ'₁ = 5/3 σ
Q'₂= 40 σπR² ⇒ σ'₂ = 5/6 σ

Φtotal = q_enclosed/ε₀

Φtotal = 0/ε₀ = 0

Uᵢ = 1/2 CV²

On switching key at point c
q₀ − q/C = q/C
2q = q₀
q = (q₀/2)

U_f = 1/2(q₀/2)² × 1/C + 1/2(q₀/2)² × 1/C
U_f= 1/4CV²
loss = 50%

Current in first branch = 2/50 A
Current in second branch = 2/50 A
ΔV from A to P
ΔV₁ = 2- 2/50 × 20
ΔV from A to Q
ΔV₂ = 2- 2/50 × 30
Voltage difference = 0.4 V

For Balanced Bridge

P/Q = l₁/l₂

On interchanging galvanometer and battery positions, balance condition remains unchanged.

B=μ₀N·I/2πR
∴ B₁/B₂ = N₁R₂/N₂R₁ = 200/100 (20/40)  = 1
So, B₁/B₂ = 1
     

Net magnetic field at point ‘P’
Bₙₑₜ = 𝐁⃗₁ + 𝐁⃗₂
Hence, Bₙₑₜ = B₁ − B₂
i₁=i(θ/2π)⇒ B₁ = μ₀i₁/2R(2π−θ/2π)
i₂=i(2π−θ/2π) ⇒ B₂= μ₀i₂/2R(θ/2π)

Here θ = π/2
Bₙₑₜ = B₁ − B₂ = 0

H= B_Ecosδ

V=B_Esinδ

A current which changes its direction periodically is called alternating current.

Using Faraday’s law
e= Bl²ω/2 = 1/2 × 0.1 × (1/2)² × 10 = 1/8 = 0.125 V

I₁ = V/Z
I₁ = 12/√R² + (XL−XC)² = 0.2 A
In second case, the capacitor would provide infinite resistance but current is present in circuit, it means resistor and inductor can be present in the circuit.
Since current with AC source and DC source are different, inductor must be present with its resistance.

When lens is cut in two half then power of one part will be same. i.e., P, as focal length remains same.

1/f = (μ-1)(1/R₁-1/R₂)

1/25=(1.5-1)(1/R+1/2R) 1/25 = 0.5(3/2R)

2R = 37.5 cm R = 18.75 cm

Path difference for destructive interference in YDSE
⇒ ΔXₙ = (2n−1) / 2 (λ) n = 1, 2, 3.....
ΔX₅ₜₕ = 9λ/2

Given

Wavelength, λ = 600 nm = 600 × 10⁻⁹ m
and diameter of objective, d = 2 m

Limit of resolution of telescope,
θ = 1.22λ/d = (1.22 × 600 × 10⁻⁹)/2

= 3.66 × 10⁻⁷ rad

As λ = h/p = h/√2mK
∴ λ ∝ 1/√m (Kinetic energies are same)
λₚ/λ_∝ = √m_∝/mₚ
∴ λₚ/ λ_α = 2/1

As E = 12400/ λ
λ = 12400/4 = 3100 Å

∴ λ = 310 nm

r ∝= 1/m
R = 0.51/207 ∴ 2.56 × 10⁻¹³ m
E ∝ m

∴ (E)_μ= 13.6 × 207 =−2.8 keV

t₁/₂ = ln2/ λ = 0.693/ λ

λ = 0.693/2.2 × 10⁻⁹ = 3.15 × 10⁻¹⁰
R = λN
N = R/λ = 10¹⁰/3.15 × 10⁻¹⁰ = 3.17 × 10¹⁹

λ = 12400/E_g Å = 12400/1.9 = 6526 Å ≈ 654 nm

λ = 12400/E_g Å = 12400/1.9 = 6526 Å ≈ 654 nm

We assume that at any instant thickness of ice is x. And time taken to form additional thickness (dx) is dt.
mL = KA(26−0)dt/x
⇒ (Adx)ρL = KA(26)dt/x
So, dx/dt = 26K/xρL

The speed of any electromagnetic wave (EM) like light in any medium of permeability μ and permittivity, ε is given by

v = 1/√(μ ε)
Also, μ = μ₀μᵣ and ε = ε₀εᵣ
where, μ₀ and ε₀ are permeability and permittivity in free

space and μᵣ and εᵣ are relative permeability and relative
permittivity of medium respectively.
Here, μᵣ= 1.0
εᵣ = 1.44
∴ v = 1/√(μᵣεᵣμ₀ε₀) = ε/√μᵣεᵣ
= 3 × 10⁸/√1 × 1.44

= 2.5 × 10⁸ ms⁻¹

Let h be the height through which the coin is dropped. Then, according to the equation of motion, it is given as

h = ut +1/2 gt² ⇒ t = √2h/g [∵ u = 0]
⇒ t ∝ 1/√g
As the elevator is moving uniformly i.e., its velocity is constant, so the acceleration is zero.
∴ Relative acceleration of the lift when it is either moving upward or downward is equal to as.
g′ = g ± a = g ± 0 = g
Hence, the time for the coin to reach the floor will remain same i.e., t₁ = t₂.

nλ = 2πr

λ = 2π/n (r)

rₙ = a₀n²

r₂ = 52.9 × (2)² pm

∴ λ = 2π/2 × 52.9 × 4

λ = 211.6π pm

Total number of nodes = (n − 1)
3 = n - 1 ⇒ n = 4
Number of angular nodes = 3 ⇒ f subshell

Na₂O → Basic oxide
Al₂O₃ → Amphoteric oxide
N₂O → Neutral
Cl₂O₇ → Acidic oxide
∵ Elements of group 1 and 2 form basic oxides while groups 13 and 14 elements form amphoteric oxides. Elements of group 16 and 17 form acidic oxides. Acidic character of oxides increases from left to right in the periodic table.

Dipole moment of a molecule is the vector sum of dipoles of bonds. Based on molecular geometry of molecules,

Molecular orbital configuration of O₂ is given as :
O₂ (16e⁻): σ1s² σ*1s² σ2s² σ*2s² σ2p² _z
π2pₓ² = π2p²ᵧ = π*2pₓ¹ = π*2p¹ᵧ
So, in O₂ molecule, there are two (2) unpaired electrons, so it is a "paramagnetic" substance in nature.

According to ideal gas equation,
PV = nRT
V = W/M (RT/P)
V = (1.8/18) × (0.083 × 647)/1 = 5.37 L

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

W = −Pₑₓₜ(V_f− Vᵢ) = −10⁵(10⁻² − 10⁻³) = −900 J

Since graph A to C represents adiabatic reversible expansion, so work is done on the expense of internal energy, therefore, there is decrease in internal energy. So temperature decreases.
i.e., T_C < T_A

Since graph A to C represents adiabatic reversible expansion, so work is done on the expense of internal energy, therefore, there is decrease in internal energy. So temperature decreases.
i.e., T_C < T_A

[OH⁻] = 0.01 M = 10⁻² M
pOH = −log[OH⁻] = −log(10⁻²) = 2
pH = 14 − pOH = 12

HCl cannot accept H⁺ therefore cannot act as Bronsted base.

Due to common ion effect of NaF, solubility of CaF₂ is further suppressed. Therefore, the concentration of F⁻ will be mainly due to NaF.
Kₛₚ = [Ca²⁺][F⁻]₂
Kₛₚ = (s)(0.1 + 2s)² 0.1 + 2s ≈ 0.1,
s = Kₛₚ /(0.1)² = 5.3 × 10⁻¹¹/ (0.1)² = 5.3 × 10⁻⁹ mol L⁻¹

+6 is the most appropriate oxidation state of Cr in CrO₆.

Lesser the reduction potential, greater is the reducing power.
Reducing power: K > Al > Cr > Ag

The actual structure of CuSO₄·5H₂O is [Cu(H₂O)₄]SO₄·H₂O, So, only one water molecule is associated with the molecule via hydrogen bond.

Only LiCl forms a dihydrate; other metal chlorides do not form hydrates.

Crude sodium chloride which is obtained by crystallisation of brine contains Na₂SO₄, CaSO₄, CaCl₂ and MgCl₂ are present as impurities in crude.

Silicones are used in cosmetic surgery.

Stability of carbocation ∝ No. of α-H.
Among the given carbocations,
is the most stable carbocation (5 α-H).

Chlorination of neopentane with Cl₂ in presence of diffused sunlight gives only one mono-chloro compound.

Liquefied CO₂ (carbon dioxide) with a suitable detergent is used in dry cleaning.

Ni₀.₉₈O = (Ni²⁺)ₓ(Ni³⁺)₀.₉₈₋ₓ(O²⁻ )₁

Net charge = 0
[x ×(2) + [(0.98 − x) × 3] + [−2 × 1] = 0
x = 0.94
Fraction of nickel existing as

Ni²⁺ = 0.94 / 0.98 = 0.959 ≈ 0.96

Let volume of solution = 1 L
Moles of NaOH = 2
Mass of NaOH solution = volume × density
= 1000 × 1.28 = 1280 g
Mass of H₂O = (1280 − 2 × 40) = 1200 g = 1.2 kg
Molality(m) = Moles of NaOH / Mass of solvent (kg) = 2 / 1.2 = 1.67 m

In case of positive deviation from ideal behaviour A-B interactions are weaker than A–A and B–B interactions.

Mole fraction of water vapour = 0.02
∴ Mole fraction of dry air = 1 − 0.02 = 0.98
Total pressure = 1.2 atm
Acc. to Dalton's law of partial pressure,

P_Dryair = P_Totalx_dry air = 1.2 × 0.98 = 1.176 atm

According to Kohlrausch's law

λ°ₘ(AB)=λ°ₘ(A⁺) + λ°ₘ(B-)

So, λ°ₘ(CH₃COOH) = λ°ₘ(CH₃COO )+λ°ₘ(H⁺)

So λ°ₘ(CH₃COOH)
= λ°ₘ(CH₃COOK) + 1/2λ°ₘ(H₂SO₄) − 1/2λ°ₘ(K₂SO₄)

= z + x/2 - y/2 = z + (x-y/2)

For a first-order reaction,
Half-life period, t₁/₂ = 0.693 / k = 0.693 / (2.303 × 10⁻³)s⁻¹ = 300.91 s
So, 40 g requires 2 half-lives to reduce to 10 g.
∴ Time taken = 2 × 300.91

= 601.82 ≈ 602 s

From Arrhenius equation,
log(k₄₀₀/k₂₀₀) = Eₐ / (2.303R)[T₂ − T₁ / T₁ T₂ ]
Since, given that Eₐ = 0,
∴ log(k₄₀₀/k₂₀₀) = 0

⇒ k₄₀₀/k₂₀₀ = 1

So, k₂₀₀=k₄₀₀

so rate constant at 400, k = 1.6 × 10⁶ s⁻¹

According to Freundlich adsorption isotherm,
x/m = kp¹ᐟⁿ ; where (n > 1)
So, x/m = kp⁰·³ as 1/n = 0.3
So, x/m = kp⁰·³ is correct

Gangue is the commercially worthless material contaminating the ore.

Hypophosphorous acid is a good reducing agent as it contains two P–H bonds.

4AgNO₃ + 2H₂O + H₃PO₂ → 4Ag + 4HNO₃ + H₃PO₄

Oleum is H₂S₂O₇.

(i) V₂O₅: Used in the oxidation of SO₂ in the manufacture of H₂SO₄ by contact process.
(ii) TiCl₄ + Al(CH₃)₃: Used in the polymerisation of ethylene.
(iii) PdCl₂: Used in the oxidation of ethyne to ethanal.
(iv) Nickel complexes: Used in the polymerisation of alkynes.

Δₜ = 4/9 Δ₀
Δₜ = 4/9× 18000 cm⁻¹ = 8000 cm⁻¹

Aryl halides do not give substitution reactions due to partial double bond character between carbon and halogen.

PCC s a mild oxidizing agent which oxidises primary alcohol to aldehyde.

Hinsberg's reagent is used to distinguish 1°, 2° and 3° amine. Primary amines react with Hinsberg's reagent to give precipitate, which is soluble in alkali while secondary amines give a product which is insoluble in alkali. Tertiary amines do not react with Hinsberg's reagent.

During denaturation, primary structure of proteins remains intact while secondary and tertiary structures are destroyed.

Polyacrylonitrile is used as a substitute for wool in making commercial fibre as Orlon or acrilan.

Sucralose is trichloro derivative of sucrose. It is stable at cooking temperature. It does not provide calories.

Selectable marker is a gene introduced into a cell, especially a bacterium or to cells in culture that confers a suitable property for artificial selection.
Selectable markers help in identification and elimination of non-transformants whilst permitting selective growth of transformants.

The Western Ghats are a chain of hills that run along the western edge of peninsular India. These regions have moist deciduous forest and rain forest. The region might host huge diversity as well as high levels of endemism. Nearly 77% of the amphibians and 62% of the reptile species found nowhere else.
Endemic species are those species that are confined to a particular region only and not found anywhere else.

Ozone is an irritating, pale blue gas that is explosive and toxic, even at low concentrations. It is mainly found in two regions of the Earth's atmosphere. About 90% of ozone resides in a layer (called stratosphere) that begins between 6 and 10 miles (10 and 17 kilometres) above the Earth's surface and extends up to about 30 miles (50 kilometres).
The ozone found in this region is commonly known as the ozone layer. The remaining ozone is in the lower region of the atmosphere, which is commonly called the troposphere. Ozone found in stratosphere are good ozone and protects us by absorbing solar ultraviolet radiation, which otherwise could cause severe damage to living organisms on the Earth's surface. Whereas ozone found in troposphere is a bad ozone and considered as a pollutant.

Bioprospecting refers to exploring molecular, genetic and species level diversity for process of discovery and commercialisation of new products of economic importance.

Polyblend is fine powder of recycled plastic waste. It was produced by plastic manufacturers in order to recycle plastic waste. When blended with bitumen, Polyblend can be used to lay roads which have increased road life.

Female wasp and fig species is not an example of commensalism. It shows mutualism in which each organism benefits from the interaction in some way. while Orchid on trees and grazing cattle with cattle egret show commensalism. Commensalism is an association between two organisms in which one benefits and the other derives neither benefit nor harm.

Irrigation of agricultural field for a prolonged time without proper drainage leads to waterlogging in the soil. Waterlogging draws salt to the surface of the soil and causes salinity.

Methanogens are anaerobic unicellular organisms that release methane as a waste product of cellular metabolism.

Mutation is the process by which genetic variations are created through changes in the base sequence within genes resulting in the creation of a new character or trait not found in the parental type. It is possible to induce mutations artificially through use of chemicals or radiations (like gamma radiations), and selecting and using the plants that have the desirable character as a source in breeding, this process is called mutation breeding.
This procedure has helped mung bean production by providing resistance against yellow mosaic virus and powdery mildew (fungal disease).

Coca alkaloids or cocaine is obtained from Erythroxylum coca, native to South America.

Biofertilisers are organisms that enrich the nutrient quality of the soil. The main sources of biofertilisers are bacteria, fungi and cyanobacteria. Cyanobacteria like Anabaena, Nostoc etc. and Rhizobium (which form root nodules in leguminous plants) are able to fix atmospheric nitrogen into organic forms which is used by the plant as nutrients.
Rhizobium and Aspergillus are used in production of other compounds of human benefit.

● DNA fragments are negatively charged molecules. They are separated by forcing them to move towards positive electrode, i.e. anode.
● Increasing the concentration of a gel reduces the migration speed of DNA.
● DNA fragment can not visualised directly but can be visualised under UV light after staining with ethidium bromide.

Restriction enzymes belong to a larger class of enzymes called nucleases. Nucleases are of two different kinds: exonucleases (which remove nucleotides from the end of a DNA molecule) and endonucleases (which break internal phosphodiester bonds at palindromic sites that are highly specific).

DNA ligase helps in ligating/joining DNA fragments. Proteases is an enzyme which breaks down proteins and peptides

RNAi (RNA interference) is triggered by double stranded RNA in a wide variety of organisms including animals, plants and fungi. It involves silencing of a specific mRNA and therefore the expression of a gene by formation of a dsRNA molecule. The dsRNA is formed by binding of a complementary RNA (antisense RNA) molecule to original mRNA thereby preventing translation of the original mRNA.

Monosporic embryo sac (also known as Polygonum type embryo sac) is the most common type of embryo sac in flowering plants which develops after one meiosis and three sequential mitosis in megaspore mother cell.
In most angiosperms, the megaspore mother cell divides by meiosis to form four haploid megaspores arranged in a linear fashion. The three haploid megaspores nearest towards the micropyle degenerate, while one remains functional which develops into the female gametophyte.

Genetic code is the sequence of nucleotides in deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) that determines the amino acid sequence of proteins. Genetic code is universal, unambiguous, non-overlapping and degenerate in nature.

Alfred Hershey and Martha Chase studied bacteriophages, or viruses that attack bacteria. In 1952, they conducted a series of experiments to prove that DNA is the genetic material. They labelled the protein of bacteriophages with radioactive sulphur and their DNA with radioactive phosphorus. The bacteriophages were allowed to infect bacteria. The protein coat is left behind while viral DNA enters a bacterium.

During transcription in eukaryotes, RNA polymerase II transcribes 5.8S, 18S and 28S rRNA.
Eukaryotic transcription is carried out in the nucleus of the cell and proceeds in three sequential stages: initiation, elongation, and termination. Eukaryotes require transcription factors to first bind to the promoter region and then help recruit the appropriate polymerase.

Klinefelter's syndrome is a chromosomal condition in boys and men that can affect physical and intellectual development. It is caused due to presence of an additional copy of X-chromosome resulting into 44 + XXY type chromosome complement. Adult with this syndrome may have primary hypogonadism (decreased testosterone production, small or undersized testes, enlarged breast, tall stature, etc.).

Eukaryotic transcription is carried out in the nucleus of the cell and proceeds in three sequential stages: initiation, elongation, and termination. Eukaryotes require transcription factors to first bind to the promoter region and then help recruit the appropriate polymerase. The sigma factor (σ) causes RNA polymerase to bind to the correct sites on DNA to initiate transcription (i.e. promoters). This enables the enzyme to identify promoter sites more rapidly and enhances the affinity and increases the amount of time that holoenzyme (α2ββ′σ) is bound to promoter, i.e. it facilitates a random search for promoters.

Agriculture came around 10,000 years back and human settlements started.
The Dryopithecus and Ramapithecus primates existed 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.

Punnett square is a graphical representation of the possible genotypes of an offspring arising from a particular cross or breeding event. With the help of Punnett square the production of gametes, the formation of zygotes and the F1 and F2 plants can be understood.

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.

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 very useful in tea leaves production.

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 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 giving the first action spectrum of photosynthesis.

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, the length of the stem increases.

Vallisneria shows epihydrophily. Epihydrophily involves transfer of pollen at the water surface. In Vallisneria male flowers after breakage float on the surface of water and reach the female flowers.

Papaya is a dioecious plant in which male and female flowers are produced on two separate plants. Hence it prevents both autogamy as well as geitonogamy. Castor and maize are monoecious and unisexual. Wheat is monoecious and bisexual.

Basal : Sunflower
Axile : China rose
Parietal : Mustard
Free central : Dianthus

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

Prosthetic groups are non-peptide (non-protein) compounds that mostly attach to proteins and assist them in different ways. They can be inorganic (like metals) or organic (carbon-containing). Prosthetic groups are tightly bound to the apoenzyme but coenzymes are associated with the apoenzyme last for a short period of time i.e. transiently.

Crossing over is the exchange of gene which takes place between non-sister chromatids of homologous chromosomes at pachytene stage of meiosis I resulting in new allelic combinations in the daughter cells.

A Ramachandran plot is a way to visualise energetically allowed regions for backbone dihedral angles ψ against Φ of amino acid residues to protein structure. It is used to analyse the structure of a protein, the conformation of the amino acids present in the protein and close contacts between the atoms.

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.

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

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.

Electron transport system is located in inner mitochondrial membrane, where it serves as the site of oxidative phosphorylation through the action of ATP synthase. Electron transport chains are redox reactions that transfer electrons from an electron donor to an electron acceptor.
The transfer of electrons is coupled to the translocation of protons across a membrane, producing a proton gradient. It is also found in the thylakoid membrane of the chloroplast in photosynthetic eukaryotes.

The first word denoting the genus starts with a capital letter while the specific epithet starts with a small letter.

Mad cow disease (or bovine spongiform encephalopathy) is a transmissible, slowly progressive, degenerative and fatal disease affecting the central nervous system of adult cattle. It's related to a disease in humans called variant Creutzfeldt-Jakob disease (vCJD). Both disorders are universally fatal brain diseases caused by a prion.
Prions are disease-causing agents having abnormally folded proteins. Prions induce other healthy proteins to fold incorrectly, leaving patches of useless debris and holes that turn brains to sponge, resulting in death. The disease has an incubation period in cattle of up to eight years.

Lichen is a symbiosis between different organisms. It is composed of a fungal partner (mycobiont) and one or more photosynthetic partners (photobiont). The photosynthetic partner is generally green algae or cyanobacteria.
Lichens are well known as sensitive indicators of air pollution, particularly for sulphur dioxide. If air is very badly polluted with sulphur dioxide there may be no lichens present, just green algae may be found. If the air is clean, shrubby, hairy and leafy lichens become abundant.

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

Vascular cambium is a secondary meristematic tissue in dicot roots. It is originated from tissue located below the phloem bundles and a portion of pericycle tissue above the protoxylem.

Alstonia shows whorled phyllotaxy. In whorled phyllotaxy, more than two leaves arise at each node and form a whorl or a circle.
China rose and mustard show alternate phyllotaxy in which a single leaf arises at each node in an alternate manner. Whereas Calotropis shows opposite type of phyllotaxy in which a pair of leaves arise at each node and lie opposite to each other.

Intercalary meristems are capable of cell division and they allow for rapid growth and regrowth of many monocots. Intercalary meristem, found in grasses, help to regenerate the parts removed by the grazing herbivores.

Bicarpellary ovary with obliquely placed septum is seen in the members of family Solanaceae.
e.g. Solanum.

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 common 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 hybridisation: Male and female animal of two different related species.

Biocontrol agents are natural enemies like parasites, predation and other mechanisms for controlling the plant pests. They play an important role in controlling the plant pests like nematodes, weeds, insects, and mites and also help in maintaining balancing of the plant species along with their natural enemies. A good biocontrol agent should be species-specific and inactive on non-target organisms.

Restriction endonuclease cleaves DNA into fragments at or near specific recognition sites within the molecule known as restriction sites.
Restriction exonuclease cleaves off nucleotides one at a time from the 3′ or 5′ ends of DNA and RNA chains.
DNA ligase facilitates the joining of DNA strands together by catalysing the formation of a phosphodiester bond.
Taq polymerase is a thermostable DNA polymerase I named after the thermophilic bacterium Thermus aquaticus from which it was originally isolated by Chien et al. in 1976. It attaches the nucleotides to a DNA template, thereby copying the DNA.

E.coli cloning vector pBR322 contains antibiotic resistance genes for Ampicillin (ampᴿ) and Tetracycline (tetR) as selectable markers.
Selectable markers help in selecting those host cells which contain the transformed vectors and eliminate the non-transformants. Plasmid pBR322 has a variety of unique recognition sites for restriction endonucleases. Two unique sites—PstI and PvuI—are located within the ampᴿ gene and BamHI and SalI are within the tetR gene.
Insertion of the DNA fragment into the plasmid using enzyme PstI or PvuI places the DNA insert within the ampᴿ gene, which makes ampR non-functional.
Bacterial cells containing such a recombinant pBR322 will be unable to grow in the presence of ampicillin but will grow on Tetracycline.

Biopiracy refers to the use of bio-resources by multinational companies and other organisations without proper authorisation from the countries and people concerned without compensation payment.
Biowar/warfare is in which disease-producing microorganism, toxin or organic biocides (e.g. Bacillus anthracis or Yersinia pestis) are used to destroy, injure or immobilise livestock, vegetation, or human life.
Bioweapon are harmful biological agents (such as a pathogenic microorganism or a neurotoxin) used as a weapon to cause death or disease usually on a large scale.
Bioethics is the study of the ethical issues emerging from advances in biology and medicine.

If two species compete for the same resource, they could avoid competition by choosing, for instance, different times for feeding or different foraging patterns. Such mechanism is called resource partitioning.

Introduction of African catfish Clarias gariepinus for aquaculture purposes has become a threat to indigenous catfishes in our rivers.
Clarias gariepinus is an alien species for the communities in Yamuna.

RNA polymerase is an enzyme that is responsible for copying a DNA sequence into an RNA sequence during the process of transcription. In eukaryotes, there are three types of RNA polymerases.
(i) RNA polymerase I transcribes rRNAs genes.
(ii) RNA polymerase II transcribes hnRNAs.
(iii) RNA polymerase III transcribes tRNAs and 5srRNA.

Male with blood group A can have genotype IA i or IAIA.
Female with blood group B can have genotype IBIB or IBi.

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 species invades a new area with many types of vacant habitats, they face different environmental pressures and eventually adapt, exhibiting adaptive radiation.

The Given diagrammatic representation showing the mechanism of protein hormone action.
'A' is a hormone such as FSH that cannot cross lipid bilayer; therefore it interacts with membrane-bound receptors and does not enter the target cell, but generates second messengers.
Peptide, polypeptide, protein hormones and catecholamines act through this mechanism.
'B' represents the extracellular receptors present on the cell surface that forms a hormone-receptor complex which brings about conformational changes in the cytoplasmic part of the receptor. This cytoplasmic part can produce second messengers such as Ca2+, cAMP, IP3 etc., which activates the existing enzyme system of the cell and accelerate the biochemical reactions of the cell.
Hence, 'C' represents the generation of second messenger.

Innate immunity is non-specific and is accomplished by providing different types of barriers to the entry of foreign agent or any pathogen into our body.
Through this immunity, the human body protects itself against foreign material that is perceived to be harmful.
Natural killer cells are a type of lymphocytes which produce proteins called perforins that create pores on plasma membrane of tumour cells and virally infected cells through which ECF enters and kills the cells.
Passive immunity is specific and is a branch of humoral immunity.
Innate immunity does not produce memory cells; hence, no secondary immune response is seen.

The correct sequence of the events is as follows:
Gametogenesis → Gamete transfer → Syngamy → Zygote cell division (Cleavage) → Cell differentiation → Organogenesis
Gametogenesis is the formation of gametes (sperm and ovum) through spermatogenesis and oogenesis respectively.
Gamete transfer is the process of bringing together male and female gamete for fertilisation.
Syngamy is fusion of gametes leading to formation of zygote.
Cleavage is the repeated (mitotic) cell division.
Cell differentiation refers to specialisation of cell to perform specific function.
Organogenesis is the formation of organs.

Foetal ejection reflex triggers release of oxytocin from the maternal anterior pituitary gland. Oxytocin acts on the uterine muscles and causes stronger uterine contractions.
Milk ejection reflex is caused by combined neurogenic and hormonal reflexes that involve release of oxytocin from posterior pituitary gland.
Relaxin, secreted by the ovary and placenta, causes the cervix to dilate and prepares the uterus for the action of oxytocin during labour.
Oestrogen, secreted from ovary, is responsible for the development and regulation of the female reproductive system and secondary sex characteristics. Prolactin, secreted from anterior pituitary, stimulates the development and milk production in women.

Ovulation is followed by the luteal phase during which the corpus luteum secretes oestrogen and progesterone hormones that exert negative feedback on the hypothalamus, which in turn inhibits the release of FSH and LH. This prevents the development of new follicles during the luteal phase.

In Australia, marsupials and placental mammals have evolved to share many similar characteristics. This type of evolution may be referred to as convergent evolution. Many placental mammals resemble the marsupial mammals not only in structure but also in leading similar ways of life. These similarities in these two different types of mammals(Marsupials and placentals) w.r.t. ancestors are due to living in the similar ecological niches. Hence, when two different types of organisms convergent evolution has occurred.

XX-XO type of sex determination is seen in crickets, grasshoppers, and some other insects. In all these organisms the female is XX and the homogametic sex. The male is heterogametic sex but only has one sex chromosome. The male in XX-XO systems produces gametes with (X) or without (O) a sex chromosome. In XX-XY method of sex determination, the sex of an individual is determined by a pair of sex chromosomes. Females typically have two of the same kind of sex chromosomes (XX), and are called the homogametic sex. Males typically have two different kinds of sex chromosomes (XY), and are called the heterogametic sex. Turner's syndrome is also known as 45, X or 45, X. It is a condition that affects only females, and results when one of the X chromosome (sex chromosome) is missing or partially missing. ZW-ZZ method of sex determination can be seen in some birds, butterflies, moths, and other organisms. Instead of X and Y chromosomes, they have Z and W chromosomes. The female is the heterogametic sex. In all these organisms female has a pair of dissimilar ZW chromosomes and male has two similar ZZ chromosomes.

5′ TACCTAGTACGTAC 3′ (Coding strand)
5′ UACCUACGUACGUA 3′ (mRNA)
In m-RNA at the place of thymine in coding strand uracil is present.

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.

Gliding joint is present between the carpals. Hinge joint is present between humerus and ulna. Pivot joint is present between atlas and axis. Saddle joint is present between carpal and metacarpal of thumb.

Myasthenia gravis is autoimmune disorder that affects neuromuscular junction leading to fatigue, weakness and paralysis of skeletal muscles.
Arthritis is inflammation of one or more joints. It is characterised by pain, stiffness and limited function of joints.
Gout, a type of metabolic arthritis (diet related) is inflammation of joints due to accumulation of uric acid crystals. It can cause painful swelling in joints and typically affects the big toe.
Osteoporosis is age related disorder characterised by decreased bone mass and increased chances of fractures. It starts with the roughening of cartilage.

Artificial light, extend work time and reduced sleep-time disrupt the activity of pineal gland.
Melatonin hormone of pineal gland plays a very important role in the regulation of a 24-hours (diurnal) rhythm of our body.
Melatonin helps in maintaining the normal rhythms of sleep-wake cycle and body temperature.

IUDs (Intra uterine devices) of all types are in general treated as a foreign body thus inviting phagocytic cells to the uterus. It is a small, T-shaped plastic and copper device.
IUDs increase phagocytosis of sperms within the uterus and Cu released suppress sperm motility and the fertilising capacity of sperms.
IUDs need to be inserted by an experienced nurse and have to be replaced after few years depending on copper or hormonal level.

AIDS and hepatitis B are sexually transmitted infections. However, they do not specifically affect the reproductive organs.
AIDS is HIV infection affecting the immune system and the opportunistic pathogens can infect various body organs.
Hepatitis B is a viral (hepatitis B virus) infection that affects liver and can cause both acute and chronic disease.
Agents causing genital herpes, genital warts and chlamydiasis produce lesions on genital organs and also directly affect the reproductive system.

During inspiration, diaphragm and external intercostal muscles contract causing increase in volume of thoracic cage. As a result intrapulmonary pressure decreases to a level less than atmospheric pressure, thus causing inspiration.
Expiration is initiated due to relaxation of diaphragm. Vital capacity is the maximum amount of air expired by a person after forceful inspiration or inspired after forceful expiration. It represents the changes in volume from completely emptied lungs to completely filled lungs. It is about 4800 ml. The value varies according to age and body size.
Total amount of air in lungs at end of forced inspiration is total lung capacity 5800 ml.

Vital capacity is the maximum amount of air expired by a person after forceful inspiration or inspired after forceful expiration. It represents the changes in volume from completely emptied lungs to completely filled lungs. It is about 4800 ml. The value varies according to age and body size. Total amount of air in lungs at end of forceful inspiration

is total lung capacity 5800 ml

SA node acts as pacemaker of heart because its autoexcitable tissue have the ability to generate heart impulse at highest rate (frequency).
This electrical impulse is then transmitted by prenodal cells, or transitional (T) cells, to the right atrium and then through the rest of the heart's electrical conduction system, eventually resulting in myocardial contraction and blood distributed to the rest of the body. The sinus node continuously generates electrical impulses, thereby setting the normal rhythm and rate in a healthy heart.

Hence, the SA node is referred to as the natural or normal pacemaker of the heart.

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 contraction.

Descending limb of Henle's loop → Reabsorption of water only
PCT → Reabsorption of ions, water and organic nutrients
Ascending limb of Henle's loop → Reabsorption of salts only
DCT → Conditional reabsorption of sodium ions and water

Podocytes: Podocytes are highly specialised cells in the Bowman's capsule in the kidneys that wrap around capillaries of the glomerulus. It plays an important role in glomerular function. Together with endothelial cells of the glomerular capillary loop and the glomerular basement membrane they form a filtration barrier.
Protonephridia: The excretory system in Amphioxus resembles the excretory system of invertebrates rather than higher chordates. Such type of excretory system is present in flatworms and polychaete annelids. The excretory organs are protonephridia.
Nephridia: It is an excretory and osmoregulatory organ of many invertebrates (such as annelid). It consists of a tubular with one end opening into the body cavity and the other opening into a pore at the body surface.
Renal calculi (also called kidney stones): Renal calculi are related to decreased urine volume or increased excretion of stone-forming components such as calcium, oxalate, urate, cystine, xanthine, and phosphate. They are common due to food in the urine and pain in the abdomen, etc.

Crista ampullaris is a sensory organ of rotation. It maintains the dynamic balance of the body. It is found in the ampulla of each of the semicircular canals of inner ear.
Otolith organ consists of two structures i.e. saccule and utricle. The projecting ridge of the saccule and utricle is called macula. The otolith function organ maintains the balance of the body.

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

Nucleolus is non-membranous nucleoplasmic structure in nucleus. Nucleolus is the site of ribosomal RNA (rRNA) synthesis.

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

Meiosis I is reductional division thus the resultant cell just after meiosis I will have half the number of chromosomes as compared to diploid parent cells. Therefore if the parent cell has 4C amount of DNA the daughter cell will have 2C amount of DNA and each gamete will have 1C amount of DNA.

Lecithin (phosphatidylcholine) is a naturally occurring fatty substance referred to as phospholipid. It is important in cell structure and metabolism.

In active 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.

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 digestion. 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.

Ophiura is an echinoderm commonly known as brittle star.
Physalia is coelenterate (cnidarian) commonly known for Portuguese man of war.
Pinctada is pearl oyster belonging to taxon bivalve mollusca.
Planaria belongs to platyhelminthes (flatworms).

Annelids exhibit bilateral symmetry with metameric segmentation where external segments correspond to internal segments.
Adult echinoderms are bilaterally symmetrical.
Aschelminthes are pseudocoelomates and platyhelminthes are acoelomates.

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

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.