datavorous/entrance-exam-dataset huggingface dataset:
Algae float on water during day time and sink during night time because

Options:
A they become light due to consumption of food material in respiration.
B they become buoyant in light due to the accumulation of oxygen bubbles released in photosynthesis.
C of accumulation of organic acids at night.
D of change in temperature.

The correct answer is:
they become buoyant in light due to the accumulation of oxygen bubbles released in photosynthesis.

Solution:
Algae float in water during day time due to accumulation of oxygen bubbles form during photosynthesis. This oxygen is utilized during the life processes and respiration and hence they sink during night.

Topic: Biology, Photosynthesis in Higher Plants, NEET
Algae have cell wall made up of

Options:
A cellulose, galactans and mannans
B hemicellulose, pectins and proteins
C pectins, cellulose and proteins
D cellulose, hemicellulose and pectins

The correct answer is:
cellulose, galactans and mannans

Solution:
Like plants, algae have cell walls contain either polysaccharides such as cellulose (a glucan) or a variety of glycoproteins or both. The inclusion of additional polysaccharide in algal cell walls is used as a feature for algal taxonomy. Mannas form microfibrils in the cell walls of a number of marine green algae including those from the genera Codium, Acetabularia as well as in the walls of some red algae like Porphyra.

Topic: Biology, Plant Kingdom, NEET, NEET 2010 (Screening)
Algae reproducing by both isogamy and anisogamy is

Options:
A Fucus.
B Volvox.
C Spirogyra.
D None of these

The correct answer is:
None of these

Solution:
Chlamydomonas is a green algae in which sexual reproduction can be isogamy, anisogamy and some species even show oogamy. Chlamydomonas shows the evolution of sexual reproduction in algae. Volvox and Fucus reproduce by oogamy and Spirogyra reproduces by isogamy.

Topic: Biology, Plant Kingdom, NEET
Algae used by Calvin and associates for photosynthetic research is

Options:
A Chlorella
B Chlamydomonas
C Volvox
D All the above

The correct answer is:
Chlorella

Solution:
Melvin Calvin used radioactive 14C in algae to study photosynthesis and his studies led to the discovery that the first CO2 fixation product was a 3-carbon organic acid. He also contributed to working out the complete biosynthetic pathway and hence it was called the Calvin cycle. Calvin used isotopes 14 C in chlorella for knowing the carbon path in photosynthesis.

Topic: Biology, Photosynthesis in Higher Plants, NEET
Algal bloom causes

a. fish mortality.
b. deterioration of water quality.
c. increased oxygen in water body.
d. control of water pollution.

Options:
A a and c
B b and d
C a and b
D b and c

The correct answer is:
a and b

Solution:
Presence of a large amount of nutrients in water causes excessive growth of planktonic algae called algal bloom. It increases the organic content of the water body that results in activation of microbes and decrease in oxygen level in water body. Thus, BOD increases, and due to toxin secretion by some algae, a large number of fish deaths occur.

Topic: Biology, Environmental Issues, NEET
Algal fungi are placed in:

Options:
A Ascomycetes
B Basidiomycetes
C Phycomycetes
D Deuteromycetes

The correct answer is:
Phycomycetes

Solution:
Many scientist (Sachs, 1874; Bessey, 1950) believe that fungi, particularly class Phycomycetes, have evolved from siphonaceous green algae. Both the group have some common features such as presence of coenocytic thalli, flagellated zoospores, streaming movement and mode of sexual reproduction. Therefore, Phycomycetes are called algal fungi.

Topic: Biology, Biological Classification, NEET
Alizarin is an example of

Options:
A Triaryl dye
B Azo dye
C Vat dye
D Anthraquinone dye

The correct answer is:
Anthraquinone dye

Solution:
Alizarin is an anthraquinone dye. It gives a bright red colour with aluminium and a blue colour with barium.

Topic: Chemistry, Chemistry in Everyday Life, NEET
Alizarine dye obtained from the root of madder plant is Anthra quinone derivative. Its structure corresponds to-

Options:
A 1,2- dihydroxy anthraquinone
B 2, 3- dihydroxy anthraquinone
C 1, 4- dihydroxy anthraquinone.
D 1- hydroxyl anthraquinone.

The correct answer is:
1,2- dihydroxy anthraquinone

Solution:
Alizarin is 1,2-dihydroxy anthraquinone having following structure.

Topic: Chemistry, Chemistry in Everyday Life, NEET
Alkali metals impart colour to Bunsen flame due to

Options:
A the presence of one electron in their outermost orbital
B low ionization energies
C their softness
D their reducing nature

The correct answer is:
low ionization energies

Solution:
Because of low ionization energy, the electron of the valence shell of alkali metals can be easily excited by the energy of the flame. When these electrons return to their original level (ground state), the excitation energy, which has been absorbed by them, is released in the form of light in the visible range.

Topic: Chemistry, s Block Elements, NEET
Alkaline-earth metals form dipositive ions, instead of unipositive ions, because

Options:
A the second ionization energy is almost double of the first ionization energy
B unipositive ions have stable configuration
C the hydration energy of dipositive ions compensates the higher value of second ionization energy
D unipositive ions are highly hydrated

The correct answer is:
the hydration energy of dipositive ions compensates the higher value of second ionization energy

Solution:
Alkaline-earth metals form dispositive ions, instead of unipositive ions, because the hydration energy of dipositive ions compensates the higher value of second ionization energy.
Heat of hydration of an ion depends upon the charge/radius ratio. Compared to the heats of hydration of alkali metal ions of comparable size, the heats of hydration of alkaline-earth metal ions are approximately four times greater, e.g., ΔHhydNa+ (size 102 pm)
=-397 kJ/mol; ΔHhydCa2+ (size 100 pm)
=-1650 kJ/mol.

Topic: Chemistry, s Block Elements, NEET
Alkane can be prepared by

Options:
A at action of Grignard's reagent with water
B the reduction of alkyl halide with H2 in presence of nickel
C the action of ethereal of alkyl halide with sodium metal
D all the above

The correct answer is:
all the above

Solution:
A. RMgBr+HOH→RH+MgBr(OH)
B. R-X+H2→NiRH+HX
C. R−X + 2Na + X−R → dry ether R−R + 2NaX
All these methods can be used to prepare alkane.

Topic: Chemistry, Hydrocarbons, NEET
Alkenes (-C=C-) and carbonyl compounds (-C=O- ), both contain a π bond but alkenes show electrophilic addition reactions whereas carbonyl compounds show nucleophilic addition reactions. Explain.

Options:
A Alkenes have a lesser electron density on the π bond, making them more susceptible to electrophilic attacks.
B Carbonyl compounds have a higher electron density on the π bond, making them more susceptible to nucleophilic attacks.
C The electronegativity of oxygen in carbonyl compounds leads to nucleophilic behavior.
D Carbon atom in carbonyl compounds acquire a slight positive charge and is attacked by nucleophile.

The correct answer is:
Carbon atom in carbonyl compounds acquire a slight positive charge and is attacked by nucleophile.

Solution:
Correct Option is : (D)
Carbon atom in carbonyl compounds acquire a slight positive charge and is attacked by nucleophile.

Topic: Chemistry, Aldehydes and Ketones, NEET
Alkyl halide undergoes sequence of reaction to form primary amine. Identify X and Y in the following sequence
C2H5Br→Xproduct→YC3H7NH2

Options:
A X=KCN,Y=H3O+
B X=KCN,Y=LiAlH4
C X=CH3Cl,Y=AlCl3/HCl
D X=CH3NH2,Y=HNO2

The correct answer is:
X=KCN,Y=LiAlH4

Solution:
C2H5Br→KCN(X)C2H5CN→LiAlH4(Y)C2H5CH2NH2(C3H7NH2)
C2H5CH2NH2(C3H7NH2)
X=KCN,Y=LiAlH4

Topic: Chemistry, Haloalkanes and Haloarenes, NEET
Alkyl halides are immiscible in water though they are polar because

Options:
A they react with water to give alcohols
B they cannot form hydrogen bonds with water
C C-X bond cannot be broken easily
D they are stable compounds and are not reactive

The correct answer is:
they cannot form hydrogen bonds with water

Solution:
Alkyl halides are immiscible in water though they are polar because they cannot form hydrogen bonds with water.

Topic: Chemistry, Haloalkanes and Haloarenes, NEET
Alkyl halides react with dialkyl copper reagents to give

Options:
A Alkenyl halides
B Alkanes
C Alkyl copper halides
D Alkenes

The correct answer is:
Alkanes

Solution:
It is a Corey House synthesis.

Topic: Chemistry, Haloalkanes and Haloarenes, NEET
Alkyl iodide reacts with NaCN to give alkyl cyanide and small amount of alkyl isocyanide. Formation of these two products is due to the

Options:
A Ionic character of NaCN
B Nucleophilic character of cyanide ion
C Ambident character of cyanide ion
D Electrophilic character of cyanide

The correct answer is:
Ambident character of cyanide ion

Solution:
Alkyl iodide reacts with NaCN to give alkyl cyanide and small amount of alkyl isocyanide. Formation of these two products is due to the ambident character of cyanide ion

Topic: Chemistry, General Organic Chemistry, NEET
Alkynes on reduction with sodium in liquid ammonia form trans alkenes. Will the butene thus formed on reduction of 2-butyne show the geometrical isomerism?

Options:
A 2-Butene is capable of showing geometrical isomerism.
B 2-Propene is capable of showing geometrical isomerism.
C 1-Butene is capable of showing geometrical isomerism.
D Butane is capable of showing geometrical isomerism.

The correct answer is:
2-Butene is capable of showing geometrical isomerism.

Solution:
Correct Option is : (A)
2-Butene is capable of showing geometrical isomerism.

Topic: Chemistry, Hydrocarbons, NEET
All aldehydes can made to undergo the Cannizzaro reaction by treatment with aluminium ethoxide. Under these conditions, the acid and alcohol are combined to form an ester. The reaction is called

Options:
A Claisen reaction
B Perkin reaction
C Aldol condensation
D Tischenko reaction

The correct answer is:
Tischenko reaction

Solution:
All aldehydes can made to undergo the Cannizzaro reaction by treatment with aluminium ethoxide. Under these conditions, the acid and alcohol are combined to form an ester. The reaction is called Tischenko reaction.
CH3CHO+CH3CHO→Al(OC2H5)3[CH3COOH+CH3CH2OH]→CH3COOCH2CH3

Topic: Chemistry, Aldehydes and Ketones, NEET
All are correct with respect to the Human Genome Project, except

Options:
A Its goal was to determine the sequence of the 3 billion chemical base pairs that make up human DNA
B Caenorhabditis elegans and Arabidopsis are the non-human model organisms, that have been sequenced
C The sequence of chromosome-1 was completed only in May 2006, this was the last of the 24 human chromosomes to be sequenced
D 14 million locations are identified in humans with single base DNA differences

The correct answer is:
14 million locations are identified in humans with single base DNA differences

Solution:
Scientists have identified about 1.4 million locations where single-base DNA differences (SNPs – single nucleotide polymorphism) occur in humans.

Topic: Biology, Molecular Basis of Inheritance, NEET
All are features of entomophilous flowers, except

Options:
A Flowers with aroma
B Versatile stamens
C Pollen grain with sticky surface
D Flowers provide reward to pollinators in the form of nectar and pollen grains

The correct answer is:
Versatile stamens

Solution:
Versatile stamens is a characteristic feature of anaemophily. Wind-pollinated flowers are usually well above the ground, the stamens are exserted and often with versatile anthers so that pollen is effectively dispersed.

Topic: Biology, Sexual Reproduction in Flowering Plants, NEET
All are in situ conservation efforts, except

Options:
A National parks
B Sanctuaries
C Herb gardens
D Biosphere reserves

The correct answer is:
Herb gardens

Solution:
Conservation of biodiversity can be done in two ways - In situ conservation and Ex-situ conservation. In situ conservation means conservation of threatened animals and plants within their natural habitat whereas when conservation is carried out outside their natural habitat in a special setting it is known as Ex-situ conservation. Botanical gardens, home gardens, Zoological parks, herb gardens and Seed banks are examples of Ex-situ conservation as the species are protected outside their natural habitat in special environment. Biosphere reserves, National parks, Sacred Groves and Wildlife Sanctuaries are examples of In situ conservation where the species are protected in their own natural habitat.

Topic: Biology, Biodiversity and its Conservation, NEET
All carbon atoms are sp2 hybridised in

Options:
A CH2=C=CH2
B 1, 3-butadiene
C CH≡C–C≡CH
D Cyclohexane

The correct answer is:
1, 3-butadiene

Solution:
It has only sp hybridized C-atoms as all carbon atoms have triple bond .

Topic: Chemistry, Chemical Bonding and Molecular Structure, NEET
All energetically effective collisions do not result in a chemical change. Explain with the help of an example.

Options:
A Chemical changes occur in all energetically effective collisions.
B All energetically effective collisions do not result in a chemical change. For example, the formation of methanol from bromoethane depends upon the orientation of the reactant molecules .The proper orientation of the reactant molecules leads to bond formation whereas improper orientation makes them simply bounce back, and no products are formed.
C Energetically effective collisions are extremely rare in chemical reactions.
D Chemical changes depend solely on the concentration of reactants.

The correct answer is:
All energetically effective collisions do not result in a chemical change. For example, the formation of methanol from bromoethane depends upon the orientation of the reactant molecules .The proper orientation of the reactant molecules leads to bond formation whereas improper orientation makes them simply bounce back, and no products are formed.

Solution:
Correct Option is : (B)
All energetically effective collisions do not result in a chemical change. For example, the formation of methanol from bromoethane depends upon the orientation of the reactant molecules .The proper orientation of the reactant molecules leads to bond formation whereas improper orientation makes them simply bounce back, and no products are formed.

Topic: Chemistry, Chemical Kinetics, NEET
All enzymes of TCA cycle are located in the mitochondrial matrix except one which is located in inner mitochondrial membranes in eukaryotes and in cytosol in prokaryotes. This enzyme is:

Options:
A isocitrate dehydrogenase
B malate dehydrogenase
C succinate dehydrogenase
D lactate dehydrogenase.

The correct answer is:
succinate dehydrogenase

Solution:
Succinate dehydrogenase provides a link between the citric acid cycleand the membrane-bound electron transport system. The enzyme catalyses the interconversion of fumarate and succinate, and is closely related to fumarate reductase.
Related Theory
The major significance of the citric acid cycle is to act as the final common pathway for the oxidation of carbohydrates, lipids and proteins, since glucose, fatty acids and many amino acids are all metabolised to acetyl CoA.

Topic: Biology, Respiration in Plants, NEET, NEET 2007
All enzymes of the TCA cycle are located in the mitochondrial matrix except one which is located in inner mitochondrial membranes in eukaryotes and in cytosol in prokaryotes. This enzyme is

Options:
A isocitrate dehydrogenase.
B ketoglutarate dehydrogenase.
C succinate dehydrogenase.
D lactate dehydrogenase.

The correct answer is:
succinate dehydrogenase.

Solution:
TCA cycle means Tricarboxylic Acid Cycle. It is a series of chemical reactions used by all aerobic organisms to release stored energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins, acetyl-CoA, is the starting point for the TCA cycle, acetyl-CoA is the product of the reaction. Succinic acid (4C) undergoes oxidation to form Fumaric acid (4C) in the presence of enzyme Succinate dehydrogenase. The hydrogen released is accepted by coenzyme FAD (Flavin Adenine Dinucleotide) and it gets reduced to form FADH2 .
All enzymes required for Krebs' cycle are present in the mitochondrial matrix except succinate dehydrogenase. Succinate dehydrogenase enzyme is attached to the inner mitochondrial membrane.

Topic: Biology, Respiration in Plants, NEET
All eukaryotic unicellular organisms belong to

Options:
A Monera
B Protista
C Fungi
D Bacteria

The correct answer is:
Protista

Solution:
Protista includes unicellular eukaryotic organisms.

Topic: Biology, Biological Classification, NEET
All eukaryotic unicellular organisms belong to the kingdom

Options:
A Monera
B Protista
C Fungi
D Animalia

The correct answer is:
Protista

Solution:
Kingdom Protista includes all single-celled eukaryotes. Protozoans, euglenoids, dinoflagellates are included in this group. Organisms in the kingdom are primarily aquatic and some show the presence of flagella and cilia.
All the chlorophyll-containing eukaryotes are included in the kingdom Plantae. All the organisms in it have cell wall made of cellulose and are autotrophic (some partial autotrophic- insectivorous plant).
Kingdom Monera includes all the prokaryotic organisms including the autotrophic and heterotrophic groups. These have non-cellulosic cell wall like Fungi but it contains varying concentration of peptidoglycan. All bacteria are included in this kingdom.
Fungi form a unique group of heterotrophic organisms showing wide diversity. These organisms have cell wall which is made of chitin unlike cellulose seen in plants. The commonly consumed mushroom and toadstool are included in this kingdom. These organisms are achlorophyllous as they are all non-photosynthetic.
Kingdom Animalia includes all the multicellular-eukaryotic animals. The organisms are heterotrophic and lack cell walls. Animals digest their food internally showing holozoic nutrition. Majority of them show capacity of locomotion.

Topic: Biology, Biological Classification, NEET
All genes located on the same chromosome ______.

Options:
A form different groups depending upon their relative distance
B form one linkage group
C do not form any linkage group
D form interactive groups that affect the phenotype

The correct answer is:
form one linkage group

Solution:
Genes are segments of DNA that make protein and facilitate the expression of characteristics.
A chromosome is a supercoiled and superfolded packaged DNA with attached proteins. The chromosomes contains the genes for various features. If many genes are located in the same chromosome and within close proximity, the genes are considered to be linked. Sucked linked genes resist recombination during the meiotic phase of cell division in gamete formation.

Topic: Biology, Principles of Inheritance and Variation, NEET
All given factors promotes absorption of water by roots except

Options:
A well-aerated soil
B highly concentrated soil solution
C optimum soil temperature
D available soil water

The correct answer is:
highly concentrated soil solution

Solution:
Water is absorbed along with mineral solutes by the root hairs, purely by diffusion; thus, if soil solution is highly concentrated, the diffusion of water inside the root cell cannot occur. Highly concentrated soil solution inhibits the absorption of water from the soil solution.

Topic: Biology, Transport in Plants, NEET
All mammals (except a few) have ___ cervical vertebra.

Options:
A Seven
B Fourteen
C Ten
D Five

The correct answer is:
Seven

Solution:
All mammals (except a few) have seven cervical vertebrae.

Topic: Biology, Locomotion and Movement, NEET
All of the following are drawbacks of Darwin's theory except

Options:
A This theory explains survival of the fittest but doesn't explain arrival of the fittest.
B This theory does not explain the development of vestigial organs
C This theory doesn't explain over-specialization of some organs like tusk of elephants
D This theory doesn't explain the cause of struggle for existence.

The correct answer is:
This theory doesn't explain the cause of struggle for existence.

Solution:
Darwin's theory on the origin of species states that over reproduction and lack of available resources causes a struggle for existence. In the struggle for existence, nature will select those organisms with favorable variations (survival of the fittest). Continuous environmental changes along with natural selection lead to the origin of species.

Topic: Biology, Evolution, NEET
All of the following are found in a prokaryotic cell, except

Options:
A mRNA
B rRNA
C snRNA
D Simultaneous transcription and translation.

The correct answer is:
snRNA

Solution:
snRNA is small nuclear RNA which is present only in eukaryotic cell synthesized by enzyme RNA polymerase III. It is used in the process of splicing of hnRNA to form functional mRNA.

Topic: Biology, Molecular Basis of Inheritance, NEET
All of the following are incorrect about evolution, except:

Options:
A Evolution is a directed process in the sense of determinism.
B In a mixed population, the one that can better adapt, will not survive.
C Evolution due to man made activity is called anthropogenic action.
D Evolution is a stochastic process based on chance events in organism and chance mutation in nature.

The correct answer is:
Evolution due to man made activity is called anthropogenic action.

Solution:
Excess use of herbicides, pesticides, etc., has only resulted in the selection of resistant varieties in a much lesser time scale. This is also true for microbes against which we employ antibiotics or drugs against eukaryotic organisms/cell. Hence, resistant organisms/cells are appearing on a time scale of months or years and not centuries. These are examples of evolution by anthropogenic action. This also tells us that evolution is not a directed process in the sense of determinism. It is a stochastic process based on chance events in nature and chance mutation in the organisms.
In a mixed population, those that can better-adapt, survive and increase in population size. Remember that no variant is completely wiped out.

Topic: Biology, Evolution, NEET
All of the following are lateral meristem, except

Options:
A fascicular cambium
B phellogen
C intercalary meristem
D interfascicular cambium

The correct answer is:
intercalary meristem

Solution:
The meristem which occurs between mature tissue is known as intercalary meristem. They occur in grasses and regenerate parts removed by the grazing herbivores. It is primary meristem and contributes to the formation of primary plant body.

Topic: Biology, Anatomy of Flowering Plants, NEET
All of the following are part of an operon except

Options:
A An enhancer
B Structural genes
C An operator
D A promoter

The correct answer is:
An enhancer

Solution:
Except for enhancer, all the given components are parts of an operon. Enhancer sequences are present in eukaryotes. When bound by specific proteins or transcription factors, these sequences enhance the transcription of an associated gene.
On the other hand, an operon is a regulatory unit of DNA containing a cluster of genes in prokaryotes.
The promoter of the operon is the site where RNA polymerase binds. The operator acts as an on-off switch to control transcription. The structural genes code for enzymes involved in metabolic pathway.

Topic: Biology, Molecular Basis of Inheritance, NEET, NEET 2018
All of the following are related to Aplysia, except:

Options:
A Triploblasitic
B Eucoelomate
C Bilaterally symmetrical
D Water vascular system

The correct answer is:
Water vascular system

Solution:
Aplysia or sea hare is a mollusc (soft-bodied animal).
Habitat: Aquatic (marine or freshwater) or terrestrial.
Symmetry: Bilaterally symmetrical.
Level of organization: Organ system level.
Triploblastic and eucoelomate.
Water vascular system is absent in molluscs and present in Echinodermata.

Topic: Biology, Animal Kingdom, NEET