datavorous/entrance-exam-dataset huggingface dataset:
One way in which the operation of $n-p-n$ transistor differs from of a $p-n-p$ :

Options:
A The emitter junction injects minority carriers into the base region of the $p-n-p$
B The emitter junction injects minority carriers into the base region of the $p-n-p$
C The emitter injects holes into the base of $n-p-n$
D The emitter junction is reversed biased in $n-p-n$

The correct answer is:
The emitter junction injects minority carriers into the base region of the $p-n-p$

Solution:
The emitter injects holes into the base of the $p-n-p$ and electrons into the base region of $n-p-n$.

Topic: Physics, Semiconductors, NEET, NEET 2013 (Karnataka)
One-litre of oxygen at a pressure of 1  atm and two-litre of nitrogen at a pressure of 0.5  atm, are introduced into a vessel of volume one-litre. If there is no change in temperature, the final pressure of the mixture of the gases [in atm] is

Options:
A 1.5
B 2.5
C 2
D 4

The correct answer is:
2

Solution:
Ideal gas equation is given by
pV=nRT ...(i)
For oxygen, p=1 atm, V=1 L, n=nO2
Therefore, Eq. (i) becomes
â´ 1Ã1=nO2RT
â nO2=1RT
For nitrogen p=0.5 atm, V=2 L, n=nN2
â´ 0.5Ã2=nN2RT
â nN2=1RT
For mixture of gas
pmixVmix=nmixRT
Here, nmix=nO2+nN2
â´ pmixVmixRT=1RT+1RT
â pmixVmix=2 (Vmix=1)

Topic: Physics, Thermodynamics, NEET
Onion is propagated through its

Options:
A tubers
B bulb
C seeds
D rhizomes

The correct answer is:
bulb

Solution:
Vegetative propagules are the plant parts or organs that are involved in the process of reproduction even though their primary function is not it. The reproductive process is called as vegetative propagation as the non-reproductive parts/organs (leaf/stem/roots) are involved.
Onion propagates vegetative by forming bulbs. Bulb is a type of modified stem that grows underground. The fleshy scale like part helps in storage of food and encloses the terminal bud. The axillary buds are found at different places. Adventitious roots form at the end that absorbs the nutrients and water. The axillary and terminal buds grow into a new stem via vegetative propagation.

Topic: Biology, Reproduction in Organisms, NEET
Only Iodine forms Hepta-fluoride IF7, but Chlorine and Bromine give Penta-fluorides. The reason for this is :

Options:
A Low electron affinity of Iodine
B Unusual pentagonal bipyramidal structure of IF7
C That the larger Iodine atom can accommodate more number of smaller Fluorine atom around it
D Low chemical reactivity of IF7

The correct answer is:
That the larger Iodine atom can accommodate more number of smaller Fluorine atom around it

Solution:
Due to larger size of iodine atom, it can accommodate upto seven small fluorine atoms around, while due to smaller sizes of chlorine and bromine atoms cannot accommodate seven fluorine atoms, i.e., steric factor dominate in case of chlorine and bromine.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), NEET
Only the green part of the plants could release oxygen in the presence of sunlight during photosynthesis was explained by

Options:
A Jan Ingenhousz
B Robert Mayer
C Malvin Calvin
D Blackman

The correct answer is:
Jan Ingenhousz

Solution:
Jan Ingenhousz (1730-1799) showed that sunlight is essential to the plant process that purifies the air fouled by burning candles or breathing animals. Ingenhousz in an elegant experiment with an aquatic plant showed that in bright sunlight, small bubbles were formed around the green parts while in the dark they did not. Later he identified these bubbles to be of oxygen. Hence he showed that it is only the green part of the plants that could release oxygen.

Topic: Biology, Photosynthesis in Higher Plants, NEET
Only two isomeric monochloro derivatives(excluding stereoisomers) are possible for

Options:
A n-butane
B 2, 3-dimethylpentane
C 2-methylpropane
D both A and C

The correct answer is:
both A and C

Solution:
Both n-butane (CH3CH2CH2CH3) and 2-methylpropane have two kinds of H's. Hence, there are two possible isomers (monochlornated) for each of these compounds

Topic: Chemistry, General Organic Chemistry, NEET
'Ontogeny recapitulates phylogeny' is the brief definition of:

Options:
A Darwinism
B Mutation theory
C Biogenetic law
D Abiogenesis

The correct answer is:
Biogenetic law

Solution:
Ontogeny recapitulates phylogeny means that during the embryonic development of any organism, its complete evolutionary history is repeated.

Topic: Biology, Evolution, NEET
"Ontogeny recapitulates phylogeny" is the statement related to

Options:
A morphology
B physiology
C taxonomy
D embryology

The correct answer is:
embryology

Solution:
There are various evidences of evolution. These include Palaentological evidences, Morphological and anatomical evidences, Embryological evidences and Biogeographical evidences. Embryological evidences means the embryonic development in various organisms is similar to that seen in ancestors. This is explained by a biogenetic law: Ontogeny recapitulates Phylogeny. This was given by Ernst Haeckel. This law explains that an organism repeats its history even during embryonic development.

Topic: Biology, Evolution, NEET
Oogenesis comprises of

Options:
A Multiplication phase
B Growth phase
C Maturation phase
D All the above

The correct answer is:
All the above

Solution:
Oogenesis is the process of formation, development, and maturation of haploid ova from diploid germinal cells of the ovary.
Oogenesis comprises of three phases
(i) Multiplication phase
(ii) Growth phase
(iii) Maturation phase.

Topic: Biology, Human Reproduction, NEET
Oparin's theory of chemical evolution was written in the book:

Options:
A Origin of species by natural selection
B Genetics and origin of species
C Origin of life
D Philosophiezoologique

The correct answer is:
Origin of life

Solution:
Alexander Ivanovich Oparin, a biochemist put forth the theory of abiogenesis in his famous book 'Origin of Life'. He theorized that life on Earth originated gradually from chemical evolution of carbon-based molecules in a 'primordial soup'. In simpler terms, life originated from non-living things via gradual reactions and increasing complexity resulting in formation of cell membranes and cell.
Origin of Species by natural selection was written by Charles Darwin who gave the theory of evolution and Philosophiezoologique was written by Lamarck who gave theory of inheritance of acquired characteristics. Theodosius Dobzhansky wrote the book Genetics and origin of species.

Topic: Biology, Evolution, NEET
Open Circulatory system is present in:

Options:
A Palaemon, Nereis, Balanoglossus
B Hirudinaria, Bombyx, Salpa
C Anopheles, Limax, Limulus
D Pheretima, Musca, Pila

The correct answer is:
Anopheles, Limax, Limulus

Solution:
The correct answer is option (3) as Anopheles (Arthropods), Limax (Mollusc) and Limulus (Arthropods) have an open circulatory system.
Option (1) is incorrect as Nereis (Annelid) has a closed circulatory system.
Option (2) is incorrect as Hirudinaria (Annelid) has a closed circulatory system.
Option (4) is incorrect as Pheretima (Annelid) has a closed circulatory system.
Arthropods (Palaemon, Bombyx, Musca) have an open circulatory system.
Hemichordates (Balanoglossus) have an open circulatory system.

Topic: Biology, Animal Kingdom, NEET, NEET 2024 (Re-NEET)
Opening and closing of stomata is due to the:

Options:
A hormonal change in guard cells.
B change in Turgor pressure of guard cells.
C gaseous exchange
D respiration.

The correct answer is:
change in Turgor pressure of guard cells.

Solution:
The guard cells are filled with chloroplasts. The guard cells are rapidly influenced by changes in the turgor pressure that regulate the opening and closing of the stomata. In the case of dicot plants, the wall of the guard cells near the pore is thick and inelastic, whereas, the outer wall is thin, elastic and semi-permeable. When the turgor develops in the guard cells, the outer thin walls expand towards the outer side. This draws the thick inner walls slightly apart and creates a pore between the two guard cells. As a result, the stomata get opened. When the guard cells lose turgor due to the loss of water, the inner walls regain their original shape. The guard cells become flaccid and
the stoma closes.
Related Theory
Usually, the number of stomata is more on the lower surface of a dorsiventral leaf (dicot leaf) while the number of stomata is same on both the surfaces of leaf in isobilateral leaves (monocot leaves).

Topic: Biology, Transport in Plants, NEET, NEET 2002
Opening of floral buds into flowers, is a type of:

Options:
A autonomic movement of variation
B paratonic movement of growth
C autonomic movement of growth
D autonomic movement of locomotion.

The correct answer is:
autonomic movement of growth

Solution:
The opening of floral buds and the change into a flower is a nastic movement. It is a type of autonomic movement of growth in which the direction of the movement isindependent of the direction of the stimulus. In fact, the response is determined by the structure of the responsive organ and not by the opposite side.
Related Theory
Paratonic growth movement are movements of curvature brought about by more growth on one side and less growth on the opposite side of plant organ induced by some external stimuli. e.g., roots move away from light and they are called negatively phototropic.

Topic: Biology, Plant - Growth and Development, NEET, NEET 2007
Opening of flower and drooping of a bud are

Options:
A Hyponasty
B Epinasty
C Curvature movement
D Spontaneous movements

The correct answer is:
Epinasty

Solution:
Nastic movements are non-directional movements in which the direction of response or movement is determined by the epinasty (greater growth on the adaxial side, e.g., the opening of flowers), hyponasty (greater growth on abaxial side e.g., closing of flowers), thigmotactic or chemonastic bending of tentacles in Drosera. Thermonastic movements occur in the opening and closing of Tulip and Crocus flowers. In epinasty opening of fern leaf and spreading of sepal and petals during the opening of the floral bud.

Topic: Biology, Plant - Growth and Development, NEET
Opening of hepatopancreatic duct into the duodenum is guarded by

Options:
A Pyloric sphincter
B Sphincter of Boyden
C Sphincter of Oddi
D Cardiac sphincter

The correct answer is:
Sphincter of Oddi

Solution:
The sphincter of ampulla or sphincter of Oddi is a muscular valve that controls the flow of digestive juices (bile and pancreatic juice) through the ampulla of Vater into the second part of the duodenum. It is named after Ruggero Oddi. The sphincter of Oddi is relaxed by the hormone cholecystokinin (CCK).

Topic: Biology, Digestion and Absorption, NEET
Opening of rectum in amphibians is termed as

Options:
A Cochlea
B Cloaca
C Coccyx
D None of these

The correct answer is:
Cloaca

Solution:
Cloaca is a terminal opening portion of the digestive excretory and reproductive system. Alimentary canal, urinary and reproductive tracts open into a common chamber called cloaca which opens to the exterior.

Topic: Biology, Animal Kingdom, NEET
Opening or blooming of the flower is known as

Options:
A anthesis
B maturation of embryo
C pollination
D dehiscence of anther lobes

The correct answer is:
anthesis

Solution:
Anthesis refers to the process of opening of the floral buds. It involves dehiscence of the anthers, attracting the pollinators, stigma receptivity, style elongation etc. Also, anthesis can be a sequential process in inflorescence. The flower during anthesis becomes functional.

Topic: Biology, Sexual Reproduction in Flowering Plants, NEET
Optical isomerism is common in which type of complexes involving didentate ligands?

Options:
A Square planar complexes
B Octahedral complexes
C Tetrahedral complexes
D Linear complexes

The correct answer is:
Octahedral complexes

Solution:
Optical isomerism is common in octahedral complexes involving didentate ligands.

Topic: Chemistry, Coordination Compounds, NEET
Oral birth control pill which is not a steroid is

Options:
A MALA- D
B Ampicillin
C MALA-N
D Saheli

The correct answer is:
Saheli

Solution:
Saheli or Ormeloxifene or centchroman is aselective estrogen receptor modulator. It is a non-steroidal oral contraceptive pill to be consumed once a week. It was developed by Central Drug Research Institute (CDRI) in Lucknow, India.

Topic: Biology, Reproductive Health, NEET
Oral contraceptive pills help in birth control by

Options:
A killing the sperms in uterus
B preventing ovulation
C forming barrier between sperm and ova
D killing the ovum

The correct answer is:
preventing ovulation

Solution:
Contraception is the avoidance of pregnancy. These include natural methods, barrier methods, intrauterine devices, chemical methods, surgical methods, oral pills, and implants. Natural methods like periodic abstinence, lactational amenorrhea and coitus interruptus prevent the meeting of sperm and ovum. Oral contraceptive methods include pills. These help birth control by preventing ovulation. These are monophasic or multiphasic.

Topic: Biology, Reproductive Health, NEET
Oral contraceptives are prescribed in females to check:

Options:
A Ovulation
B Fertilization
C Implantation
D Entry of sperms in vagina

The correct answer is:
Ovulation

Solution:
Oral contraceptives are prescribed in females to check ovulation. Oral contraceptives, also known as birth control pills, contain artificially made forms of two hormones produced naturally in the body. These hormones, estrogen and progestin, regulate a woman's menstrual cycle. When taken in the proper amounts, following a specific schedule, oral contraceptives are very effective in preventing pregnancy.

Topic: Biology, Reproductive Health, NEET
Oral contraceptives help in preventing pregnancy by inhibiting

Options:
A Ova formation
B Fertilization
C Implantation
D None of these

The correct answer is:
Ova formation

Solution:
Progesterone only pills (POP) is a contraceptive pill that helps in preventing pregnancy by not allowing the formation of ova, as progesterone inhibits the development of FSH and LH.

Topic: Biology, Reproductive Health, NEET
Orbital having 3 angular nodes and 3 total nodes is

Options:
A $5 p$
B $3 d$
C $4 f$
D $6 d$

The correct answer is:
$4 f$

Solution:
Angular node (l) $=3$
Total node $=$ radial node + angular node
$$
\begin{aligned}
& 3=(\mathrm{n}-\mathrm{l}-\mathrm{l})+\mathrm{l} \\
& 3=\mathrm{n}-\mathrm{l} \Rightarrow \mathrm{n}=4
\end{aligned}
$$
$\therefore$ Orbital having 3 angular nodes and 3 total nodes is $=n l=4 \mathrm{f}[\because \mathrm{l}=3$ for $\mathrm{f}$ - orbital $]$

Topic: Chemistry, Structure of Atom, NEET, NEET 2019 (Odisha)
Order of rate of reaction of following compounds with AgNO3 (following SN1 mechanism).

Options:
A II > III > I
B III > II
C I > II > III
D III > I > II

The correct answer is:
I > II > III

Solution:
Here the reactivity order is
(I) becomes aromatic after removal of Cl-
(II) non aromatic after removal of Cl-
(III) becomes anti aromatic after removal of Cl-

Topic: Chemistry, Haloalkanes and Haloarenes, NEET
Ordinary hydrogen at room temperature is a mixture of –

Options:
A 75% o-Hydrogen + 25% p-Hydrogen
B 25% o-Hydrogen + 75% p-Hydrogen
C 50% o-Hydrogen + 50% p-Hydrogen
D 1% o-Hydrogen + 99% p-Hydrogen

The correct answer is:
75% o-Hydrogen + 25% p-Hydrogen

Solution:
Ordinary hydrogen can exist in two allotropic form depending on whether their electron spin is parallel or antiparallel. They contain 75% o-Hydrogen and 25% p-hydrogen.

Topic: Chemistry, s Block Elements, NEET
Organ of corti is located on the _________

Options:
A Basilar membrane
B Basement membrane
C Reissner membrane
D Synovial membrane

The correct answer is:
Basilar membrane

Solution:
The organ of Corti, or spiral organ, is the receptor organ for hearing and is located in the mammalian cochlea. The basilar membrane within the cochlea of the inner ear is a stiff structural element that separates two liquid-filled tubes that run along the coil of the cochlea, the scala media and the scala tympani.
The organ of Corti is a structure located on the basilar membrane which contains hair cells that act as auditory receptors. The hair cells are present in rows on the internal side of the organ of Corti. The basal end of the hair cell is in close contact with the afferent nerve fibres.

Topic: Biology, Neural Control and Coordination, NEET
Organ system level of organisation is observed in

Options:
A Chordates
B Annelids
C Mollusca
D All of these

The correct answer is:
All of these

Solution:
Organ system level of organisation is seen in chordates, annelids and mollusc. i.e., in all the phyla from platyhelminthes on wards.

Topic: Biology, Animal Kingdom, NEET
Organic compound firmly bound to an apoenzyme to make it catalytically active is

Options:
A Coenzyme
B Metal ion
C Prosthetic group
D Holoenzyme

The correct answer is:
Prosthetic group

Solution:
Cofactors are the non-protein constituents that bound to an enzyme to make it catalytically active.
Cofactors can be of 3 types:
1. Prosthetic groups: Organic compound firmly bound to an apoenzyme, e.g., haem is a prosthetic group for peroxidase and catalase which mediates the breakdown of hydrogen peroxide to water and oxygen.
2. Coenzymes: Organic compound loosely bound to an apoenzyme, e.g., most of the members of the vitamin B complex. Coenzymes NAD (nicotinamide adenine dinucleotide) and NADP (nicotinamide adenine dinucleotide phosphate) contain vitamin niacin.
3. Metal ions: These form coordination bonds with the side chains at the active site of the enzyme and simultaneously with 1 or more coordination bonds with the substrate, e.g., zinc act as a cofactor for carboxypeptidase enzyme.

Topic: Chemistry, Biomolecules, NEET
Organic compounds synthesis in the plant is transported in which of the following ways in flowering plants:

Options:
A Leaves to other parts only
B From leaves to other part and storage organ
C Re exported from storage organ to other part
D Both (B) and (C)

The correct answer is:
Both (B) and (C)

Solution:
Compounds synthesised in the photosynthetic leaves are exported to all other parts of the plant including storage organs. From the storage organ they are later re-exported.

Topic: Biology, Transport in Plants, NEET
Organic liquid vaporizes at a temperature below its boiling point in steam distillation because

Options:
A Mixture boils when sum of vapour pressure of water and organic liquid becomes equal to atmospheric pressure.
B Steam distillation is actually distillation under increased pressure.
C Water vapour does not contribute to its boiling point.
D Atmospheric pressure is reduced.

The correct answer is:
Mixture boils when sum of vapour pressure of water and organic liquid becomes equal to atmospheric pressure.

Solution:
P=P1+P2
P=atmospheric pressure
P1= Vapour pressure of organic liquid
P2= Vapour pressure of water
∴P1=P-P2

Topic: Chemistry, General Organic Chemistry, NEET
Organic substances such as sugars are translocated in the phloem. This phenomenon was shown by

Options:
A Girdling experiment
B Root pressure theory
C Experiment by Dixon and Jolly
D Munch hypothesis

The correct answer is:
Girdling experiment

Solution:
Girdling experiment is a process used to identify the tissues involved in food transport. On the trunk of a tree a ring of barkup to a depth of the phloem layer is removed. It was observed that downward movement of food was not there, the portion of the bark above the ring on the stem became swollen after few weeks. This showed that phloem is the tissue responsible for translocation of food.

Topic: Biology, Transport in Plants, NEET
Organic substrates that are oxidised during respiration to liberate energy inside the living cells are called ___.

Options:
A Respiration
B Respiratory substrates
C Respiratory quotient
D None of the above

The correct answer is:
Respiratory substrates

Solution:
Organic substrates that are oxidised during respiration to liberate energy inside the living cells are called Respiratory substrates

Topic: Biology, Respiration in Plants, NEET
___ organisms have division of labour.

Options:
A Unicellular
B Pseudocellular
C Multicellular
D None of the above

The correct answer is:
Multicellular

Solution:
Multicellular organisms have division of labour.

Topic: Biology, Cell - The Unit of Life, NEET
Organisms living in salty areas are called as

Options:
A Methanogens
B Halophiles
C Heliophytes
D Thermoacidophiles

The correct answer is:
Halophiles

Solution:
Organisms living in salty areas are called Halophiles.

Topic: Biology, Biological Classification, NEET
Organisms that can tolerate and thrive in a wide range of temperature are called

Options:
A Stenothermal
B Homeotherms
C Poikilotherms
D Eurythermal

The correct answer is:
Eurythermal

Solution:
Eurythermal organisms can tolerate large changes in temperature. Stenothermal are those organisms that only survive in a narrow temperature range. Homeotherms have constant and relatively high body temperature. Poikilotherms are organisms that cannot regulate their body temperature.

Topic: Biology, Organisms and Populations, NEET
Organisms which obtain energy by the oxidation of reduced inorganic compounds are called:

Options:
A photoautotrophs
B chemoautotrophs
C saprozoic
D coproheterotrophs

The correct answer is:
chemoautotrophs

Solution:
Chemotrophs are organisms that obtain energy by the oxidation of reduced compounds. Chemoautotrophs use inorganic energy sources and are known as chemolithoautotrophs or lithoautotrophs
Related Theory
Chemolithoheterotrophs are a special kind of chemotroph that use inorganic compounds as an energy source and reduced organic compounds as a carbon source. Chemotrophs use fermentation and respiration to obtain energy.

Topic: Biology, Biological Classification, NEET, NEET 2002
Organisms which obtain energy by the oxidation of reduced inorganic compounds are called

Options:
A Photoautotrophs
B Chemoautotrophs
C Saprozoic
D Coproheterotrophs

The correct answer is:
Chemoautotrophs

Solution:
The organisms obtaining energy by chemical reactions independent of light are called chemotrophs. When the reductants are obtained from the environment in an inorganic form, the organisms are chemoautotrophs. When the reductants are organic, the organisms are chemoheterotrophs.
Photoautotrophs make their food by photosynthesis using the energy of the sun. Saprozoic organisms obtain food from dead and decaying matter.

Topic: Biology, Biological Classification, NEET
Ornamentals belonging to family Liliaceae are

Options:
A tulip and petunia
B gloriosa and tulip
C gloriosa and lupin
D lupin and sesbania

The correct answer is:
gloriosa and tulip

Solution:
Plants grown for decorative purposes in gardens, houses, and landscapes are called ornamental plants. Liliaceae is a family from the Angiosperm that is the characteristic representative of the monocotyledonous plant group. It is also commonly called as "Lily family".
Many plants from the family are economically important as a source of medicine - Aloe, vegetables - Asparagus, also as ornamental plants like tulip and gloriosa.

Topic: Biology, Morphology of Flowering Plants, NEET
Ornithorhynchus belongs to which class.

Options:
A Aves
B Reptilia
C Mammalia
D Amphibia

The correct answer is:
Mammalia

Solution:
Ornithorhynchus(Platypus) belongs to class Mammalia.

Topic: Biology, Animal Kingdom, NEET
Orthoboric acid when heated to red hot gives:

Options:
A metaboric acid
B pyroboric acid
C boron and water
D diboron trioxide

The correct answer is:
diboron trioxide

Solution:
H 3 BO 3 → -H 2 O Δ/100 o C HBO 2 → -160 o C Δ H 4 B 2 O 7 → Red Hot  >  250 o  C Δ B 2 O 3   +2H 2 O

Topic: Chemistry, p Block Elements (Group 13 & 14), NEET