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Correct option (1) Elephantiasis

Explanation

Elephantiasis is a helminthic disease caused by Wuchereria bancrofti. The infestation is transmitted by female Culex mosquitoes from one individual to the others. The worms live in the lymphatic system. 

Ascariasis is caused by Ascaris lumbricoides. It is an endoparasite of the small intestine of human beings. 

Amoebiasis is caused by Entamoeba histolytica. It lives in the large intestine of humans. Ringworm is a fungal skin disease.

Correct Option(4) Francois Jacob and Jacques Monod – Lac operon 

Explanation:

Jacob and Monod (1916) discovered the lac operon. An operon is a part of the genetic material or DNA which acts as a single regulated unit. lt possesses one or more structural genes, an operator gene, a promoter gene, a regulator gene, a repressor gene, and an inducer or corepressor.

Matthew Meselson and F Stahl discovered the semi-conservative mode of DNA replication in E. coli. Alfred Hershey and Martha Chase use T₂ Bacteriophage in their experiments to infect E. coli and proved that DNA is the genetic material. Alec Jeffreys (1984) invented the DNA fingerprinting technique. This technique determines nucleotide sequences of certain areas of DNA which are unique to each individual.

The correct answer is (4)

 In Human RBCs, nucleus get degenerates during maturation and it provide more space for oxygen carrying pigment (Haemoglobin). It lacks many cell organelles including mitochondria so respires anaerobically.

Answer is : (c) IV and V

Pollination by snails is called malacophily and by ants is called myrmecophily, e.g. Anemone nemarosa.

The correct answer is (4)

 Myelin sheath wrapped around the nerve axon. Oligodendrocytes are neuroglial cells which produce myelin sheath in central nervous system while Schwann cell produces myelin sheath in peripheral nervous system.

The correct answer is (3)

Pre-synaptic membrane is involved in the release of neurotransmitter in the chemical synapse. The receptors sites for neurotransmitters are present on postsynaptic membrane of neuron

 The correct answer is (1)

Insect pollinated plants provide rewards as edible pollen grain and nectar as usual rewards. In order to materialize and maximize pollination flowers have developed a set of attributes which areaimed at attracting the pollinators called attractants

Answer is : (b) S-phase

Synthesis of the DNA and the histone proteins takes place during the S-phase (synthetic phase) of interphase in cell cycle.

In this phase, the cell synthesises a replica of its genome by the process of DNA replication. Thus, DNA content becomes doubled.

Answer : (d) I > III > II > IV

Piperidine and morpholine both are non-aromatic and N-atom is sp³ hybridised in them, so these are more basic as compared to other two (which are aromatic and have sp² hybridised N-atom). 

-I-effect of O-atom in morpholine makes it less basic as compared to piperidine. 

Now,

Out of pyridine and pyrolle, pyridine is much stronger base as the lone pair of nitrogen atom in pyridine is not involved in resonance. 

So, 

The order of basic strength is : 

I > III > II > IV.

Answer : (c) tetradentate 

The ligand N(CH₂CH₂NH₂)₃ is tetradentate.

The given ligand have four donor atoms.

They donate four pair of electrons to metal ion.

The correct option is (2) 2 A.

Explanation:

When switch in closed, then current will only flow through R₂. The surface resistor arm

So, i = i₁

Hence, i = i₁ = E/R₂ = 18/9 = 2 A

Correct option [c] matix of mitochondria 

Answer is : (a) inability to accept more than 40 - 50 kbp of DNA

The major disadvantage of cosmids is their inability to accept more than 40 - 50 kbp of DNA. Cosmids are the vectors, which can accommodate DNA segments upto 45 kbp.

Answer is : (b) α - helix, β - pleated sheet

The two important types of secondary structures of proteins are α - helix and β - pleated sheet. β - sheets consist of β - strands connected laterally by atleast two or three backbone H - bonds, forming a generally twisted, pleated sheet. A β - strand is a stretch of polypeptide chain, 3 -10 amino acids long with backbone in an extended conformation.

In α - helix, the chain is spirally coiled, generally in a right - handed manner. This structure is formed through H - bonding in single amino acid chain only.

Answer is : (d) Either (a) or (b)

According to Blackman’s law, when a process depends on a number of factors, its rate is limited by the pace of the slowest factor. Therefore, at a particular time, photosynthesis can be limited by CO₂ concentration or light.

The correct answer is (3

 In hepatic portal system, hepatic portal vein drains blood to liver from intestine.

Correct option [b] isoenzyme

Answer is : (d) Electron cloud between two C - atoms is cylindrically symmetrical

Ethyne molecule is a linear molecule which consists of one C - C σ - bonds, two C - H σ - bonds and two C - C π - bonds. Electron cloud between two C - atoms is cylindrically symmetrical about the internuclear axis.

Answer is :  (b) IV > II > III > I

+M effect of — NH₂ > +M of —OH group that disperse the charge of carbocation. Hence, increases the stability —CH₃ group shows + I effect, so it will disperse the charge less than —NH₂, —OH group whereas —NO₂ group shows —M/—I effect due to which the positive charge on the carbocation increases. Hence, stability decreases.

Answer is : (c) Hydrophobic effect

Except hydrophobic effect, all the given are involved in the tertiary structure of proteins.

Answer is : (c) 0.68 M

M = \(\frac{M_1V_1+M_2V_2}{V_1+V_2}\)

\(=\frac{0.6\times 800+1\times 200}{1000}\)

\(=\frac{480+200}{1000}\)

\(=\frac{680}{1000}\) 

= 0.68 M

The correct option is(c) Uniflagellate gametes - Polysiphonia

Explanation:

Polysiphonia is a red algae. In it sexual reproduction is of oogamous type. The male sex organ, spermatangium produces non-flagellate male gametes.

In Brown algae, sexual reproduction varies from isogamy, anisogamy to oogamy. In isogamy and anisogamy both the gametes are motile while in oogamy only male gametes are motile. These motile gametes have two unequal laterally attached flagella.

Chlorella is a unicellular organism. It is green algae belonging to class Chlorophyta. In Marchantia, gemma cups are found on its dorsal surface. It contains gammae which help in vegetative propagation.

Answer is : (d) gibberellins

Gibberellins break the dormancy of seeds due to environmental conditions and promote germination. Seed dormancy sets in the seeds to overcome the unfavourable conditions for seedling and germination.

Correct Option (a) tranquilizers

Correct Option (a) A 

Answer is : (a) Surfactants secreted by the clara cells prevent the collapse

Pulmonary surfactant is a mixture of lipids and proteins which is secreted by the epithelial cells, viz. clara cells. Its main function is to reduce surface tension, thereby preventing the bronchioles and the lungs from collapsing.

Answer is : (c) K₂MnO₄

2MnO₂ + 4KOH + O₂ \(\rightarrow \underset{\text{Purple green}}{2K_2MnO_4}\) + 2H₂O

Answer is : (d) Hippocampus

Hippocampus (seahorse) is a marine bony fish having bony plates and scutes besides scales. It has a brood pouch on the belly of males for incubating eggs.

Answer is : (c) axillary buds are inhibited by auxin

Apical dominance is a condition where, axillary buds are inhibited by auxin produced by apical meristem. When apical meristem is removed, the axillary bud becomes free from hormone inhibition and like apical meristem, it develops into a stem or flower.

(4) Cu²⁺ interfere in the sperm movement, which suppress the sperm motility and fertilising capacity of sperms.

The correct answer is (2)

 Primary treatment is a physical process which involves two process, i.e. filtration and sedimentation of big solid waste.

The correct answer is (1)

Hershey and Chase proved that DNA as genetic material. They used bacteriophage for their experiment.

The correct answer is (2)

Pharyngeal gill slits are present in hemichordates and in chordates. Notochord is present in chordates only. Ventral tubular nerve cord is present in non-chordates.

Correct Option (d) C

Explanation :

Answer is : (c) cohesin

Cohesin is a multi-subunit protein complex that holds the sister chromatids together after DNA replication, i.e. in prophase and metaphase, during anaphase removal of cohesin leads to the separation of sister chromatids.

Answer is : (a) nucleic acid is the only active part of a virus

Viruses are known as wandering genes because nucleic acid is the only active part of it. The infectivity of virus is due to nucleic acid, while host specificity is determined by the protein coat.

Answer is : (b) inspiratory capacity

Total volume of air a person can inspire after a normal expiration is the inspiratory capacity. It includes Tidal Volume (TV) + Inspiratory Reserve Volume (IRV).

Answer is : (a) Connective tissue

Benign tumour does not invade other tissues or spread to other sites. It is usually well-encapsulated in connective tissue

The correct option is (4).

Answer is : (a) 36

EAN = (atomic number - oxidation state + 2 x CN)

= 27 - 3 + 2 x 6

= 24 + 12 = 36

Answer given below:

https://bit.ly/2VepkUz

Correct option (d) C₂H₅O^– > OH^– > Cl^– > Br^– > I^–

Explanation:

Weaker the acid, stronger is the conjugate base and stronger is nucleophilicity. The order of nucleophilicity is C₂H₅O^– > OH^– > Cl^– > Br^– > I^–

Correct option (a) Their greater enthalpy of atomization 

The correct option is (1) 25 N.

Explanation:

Slope under (v-t) curve gives acceleration 

a = 0.5 m/s²

Force = m x a 

= 50 x 0.5

= 25 N

It is correct statement.

 Inbreeding helps in accumulation of superior genes and elimination of undesirable genes.

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, increase the productivity of inbred population. Close and continued inbreeding usually reduces fertility and even productivity.

Answer : (d) adsorption 

Chromatography is based on the principle of differential adsorption of different components over an adsorbent. 

In this method, 

Weakly adsorbed component is eluted first and the strongly adsorbed component is elucted afterwards.

Answer : (c) 0

CO is a neutral ligand.

∴Oxidation state of Ni in [Ni(CO)₄] is 0.

Answer is :  (b) 7.7 cm, 411.65 ms⁻¹

End correction = \(\frac{L_2-3L_1}{2}\)

\(=\frac{112.9-3\times 32.5}{2}\)

\(=\frac{15.4}{2}=7.7\, cm\)

Speed of sound in air,

v = 2v(L₂ - L₁)

= 2 x 256 x (1.129 - 0.325)

= 411.65 ms^-1.

Correct option (c) [Fe(C₂O₄)₃]^3– 

Explanation:

 The central metal ion is Fe³⁺ and C₂O₄ ^2– is negative bi-dentate ligand which forms more stable complex than neutral or monodentate ligand.

Answer is : (b) metaxenia

Term metaxenia is used for denoting the effect of pollens on structure outside endosperm.

Xenia refers to the effect of pollen on seeds and fruit in a fertilised plant.