KVPY Class-XII (SB/SX)

TIME LEFT -

Question 1
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Let f: [0, 1] → [-1, 1] and g: [-1, 1] → [0, 2] be two functions such that g is injective and g° f: [0, 1] → [0, 2] is surjective. Then,

A
f must be injective but need not be surjective

B
f must be surjective but need not be injective

C
f must be bijective

D
f must be a constant function

Question 2
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A thin metallic disc is rotating with constant angular velocity about a vertical axis that is perpendicular to its plane and passes through its centre. The rotation causes the free electrons in the disc to redistribute.

Assume that there is no external electric or magnetic field. Then,

A
a point on the rim of the disc is at a higher potential than the centre.

B
a point on the rim of the disc is at a lower potential than the centre.

C
a point on the rim of the disc is at the same potential as the centre.

D
the potential in the material has an extremum between center and the rim.

Question 3
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The ionic radii of Na⁺, F^-, O^2-and N^3- follow the order:

A
O^2- > F^- > Na⁺ > N^3-

B
N^3- > Na⁺ > F^- > O^2-

C
N^3- > O^2- > F^- > Na⁺

D
Na⁺ > F^- > O^2- > N^3-

Question 4
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Among C, S and P, the element(s) that produce(s) SO₂ on reaction with hot conc. H₂SO₄ is/are

A
only S

B
both C and S

C
both S and P

D
C, S and P

Question 5
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The tendency of X in BX₃ (X = F, Cl, OMe, NMe) to form a bond with boron follows the order:

A
BCl₃ < BF₃ < B(OMe)₃ < B(NMe₂)₃

B
BF₃ < BCl₃ < B(OMe)₃ < B(NMe₂)₃

C
BCl₃ < B(NMe₂)₃ < B(OMe)₃ < BF₃

D
BCl₃ < BF₃ < B(NMe₂)₃ < B(OMe)₃

Question 6
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Consider the following statements about Langmuir isotherm:

(i) The free gas and adsorbed gas are in dynamic equilibrium.
(ii) All adsorption sites are equivalent.
(iii) The initially adsorbed layer can act as a substrate for further adsorption.
(iv) The ability of a molecule to get adsorbed at a given site is independent of the occupation of neighboring sites.

The correct statements are:

A
(i), (ii), (iii) and (iv)

B
Only (i), (iii) and (iv)

C
Only (i), (ii) and (iv)

D
only (i), (ii) and (iii)

Question 7
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A buffer solution can be prepared by mixing equal volumes of

A
0.2 M NH₄OH and 0.1 M HCl

B
0.2 M NH₄OH and 0.2 M HCl

C
0.2 M NaOH and 0.1 M CH₃COOH

D
0.1 M NH₄OH and 0.2 M HCl

Question 8
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What is the maximum number of oxygen atoms that a molecule of hemoglobin can bind?

A
23

B
4

C
8

D
16

Question 9
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Bt toxin, produced by Bacillus thuringiensis, does not kill the producer because the toxin is

A
in an inactive protoxin form

B
rapidly secreted outside

C
inactivated by an antitoxin

D
in unfolded form

Question 10
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An angiosperm was identified with its endosperm of 6n. Assuming that it is a self-pollinating species, which ONE of the following is the correct ploidy of the parent?

A
3n

B
4n

C
6n

D
8n

Question 11
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Which ONE of the following statements is TRUE about viruses?

A
All viruses possess a protein coat around its genetic material at all stages of their life cycle.

B
All viruses contain RNA as genetic material.

C
All viruses contain DNA as genetic material.

D
All viruses replicate only within the host cell.

Question 12
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Mitochondrial cristae are infoldings of the:

A
outer membrane and they increase the surface area

B
outer membrane and they decrease the surface area

C
inner membrane and they increase the surface area

D
inner membrane and they decrease the surface area

Question 13
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In biological nitrogen fixation the enzyme nitrogenase converts:

A
nitrate to nitrite

B
atmospheric nitrogen to nitrite

C
nitrite to ammonia

D
atmospheric nitrogen to ammonia

Question 14
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Which ONE of the following properties of normal cell is lost during its transition to cancerous cell?

A
Gluratamine utilization

B
Contact inhibition

C
Glucose utilization

D
Membrane fluidity

Question 15
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Which ONE of the following gases is produced during fermentation by yeast?

A
CO₂

B
O₂

C
H₂

D
N₂

Question 16
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Serine proteases are called so because they-

A
require free serine for their activity

B
cleave after serine residues in the substrate

C
are inhibited by the presence of free serine

D
have a serine residue at their active site

Question 17
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The maximum number of gametes of the pollens produced by a tall pea plant with round, yellow seeds of the genotype TtRrYY, if the three loci are unlinked, would be:

A
1

B
2

C
4

D
8

Question 18
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Which ONE of the following statements is TRUE with respect to human ovary?

A
Estrogen is secreted by Graafian follicles and progesterone by corpus luteum

B
Estrogen is secreted by corpus luteum and progesterone by Graafian follicles

C
Both estrogen and progesterone are secreted by Graafian follicles

D
Both estrogen and progesterone are secreted by corpus luteum

Question 19
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Which ONE of the following statements is INCORRECT with respect to human antibodies?

A
They can neutralize microbes

B
They are synthesised by T cells

C
They are made up of four polypeptide chains

D
Milk contains antibodies

Question 20
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Concentration (%) of NaCl isotonic to human blood is

A
0.085-0.09%

B
1.7-1.8%

C
3.4-3.6%

D
0.85-0.9%

Question 21
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Which of the following statements is TRUE about the golgi apparatus?

A
It is found only in animals.

B
It is found only in prokaryotes.

C
It modifies and targets proteins to the plasma membrane.

D
It is a site for ATP production.

Question 22
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Creutzfeldt Jakob Disease (CJD) is a transmissible disease caused by a:

A
Virus

B
Bacterium

C
Fungus

D
Misfolded protein

Question 23
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A researcher found petrified dinosaur faeces. Which of the following is unlikely to be found in this fossil?

A
Decayed conifer wood

B
Bamboo

C
Cycad

D
Giant fern

Question 24
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Which of the pairs of amino-acids contains two chiral centres?

A
Isoleucine and threonine

B
Leucine and valine

C
Valine and isoleucine

D
Threonine and leucine

Question 25
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In photosynthetic carbon fixation, which of the following reacts with CO₂?

A
Phosphoglycolate

B
3-Phosphoglycerate

C
Ribulose-1,5-bisphosphate

D
Ribulose-5-phosphate

Question 26

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Match the diseases in Column-I with the routes of infection in Column-II. Choose the CORRECT combination.

Column-I	Column-II
P. Tuberculosis	i. Contaminated food and water
Q. Dysentry	ii. inhalation of aerosol
R. Filariasis	iii. Contact via skin
S. Syphilis	iv. Sexual intercourse
-	v. Mosquito bite

P - ii, Q - i, R - v, S - iv

P - ii, Q - i, R - iii, S - v

P - i, Q - iii, R - v, S - iv

P - ii, Q - iii, R - iv, S - v

Question 27
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Suppose z is any root of 11z⁸ + 20 iz⁷ + 10iz - 22 = 0, where i = √-1. Then, S = |z|² + |z| +1 satisfies

A
S ≤ 3

B
3 < S < 7

C
7 ≤ S < 13

D
S ≥ 13

Question 28
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Among Ce (4f¹ 5d¹ 6s²), Nd (4f⁴ 6s²), Eu (4f⁷ 6s²) and Dy (4f¹⁰ 6s²), the elements having highest and lowest 3^rd ionization energies, respectively, are

A
Nd and Ce

B
Eu and Ce

C
Cu and Dy

D
Dy and Nd

Question 29
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Tetrapeptide is made of naturally occurring alanine, serine, glycine and valine. If the C-terminal amino acid is alanine and the N-terminal amino acid is chiral, the number of possible sequences of the tetrapeptide is

A
12

B
8

C
6

D
4

Question 30
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What is the probability that a human individual would receive the entire haploid set of chromosomes from his/her grandfather?

A
1/2

B
(1/2)²³

C
(1/2)²

D
(1/2)⁴⁶

Question 31
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Which ONE of the following primer pairs would amplify the fragment of DNA given below?

5'-CTAGTCGTCGAT-(N)_300-GACTGAGCTGAGCTG-3'
3'-GATCAGCAGCTA-(N)_300-CTGACTCGACTCGAC-5'

A
5'-CTAGTCGTCGAT-3' and 5'-GACTGAGCTGAGCTG-3'

B
5'-CTGACTCGACTCGAC-3' and 5'-CTAGTCGTCGAT-3'

C
5'-CTAGTCGTCGAT-3' and 5'-CAGCTCAGCTCAGTC-3'

D
5'-CTAGTCGTCGAT-3' and 5'-GTCGAGTCGAGTCAG-3'

Question 32
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How many different blood groups are possible in a diploid species with ABCO blood grouping system involving I^A, I^B, I^Cand I^Oalleles (I^Ois recessive and others are co-dominant)?

A
4

B
6

C
7

D
8

Question 33
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Within the exponential phase of growth, if the initial surface area and the growth rate of a leaf are 10 mm² and 0.015 mm²/hour, respectively, the area of the leaf after 4 days would range from

A
10 to 12 mm²

B
20 to 24 mm²

C
30 to 36 mm²

D
40 to 48 mm²

Question 34
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If the acidic, basic and hydrophobic residues of proteins are considered to be red, green and blue in colour, respectively, then a globular protein in aqueous solution would have

A
red and blue on the surface and green at the core

B
red and green on the surface and blue at the core

C
blue on the surface and red and green at the core

D
blue and green on the surface and red at the core

Question 35

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Match the vitamins listed in Column - I with their respective coenzyme form in Column - II. Choose the correct combination.

Column - I	Column - II
P. Vitamin B₁	i. Thiamine pyrophosphate
Q. Vitamin B₂	ii. Flavin adenine dinucleotide
R. Vitamin B₆	iii. Methylcobalamin
S. Vitamin B₁₂	iv. Coenzyme A
	v. Pyridoxal phosphate

P - v, Q - iii, R - i, S - iv

P - iii, Q - iv, R - ii, S - i

P - i, Q - ii, R - v, S - iii

P - i, Q - iv, R - ii, S - iii

Question 36
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Two independent experiments related to photosynthesis were conducted - one with ¹⁸O-labelled water (experiment P) and the other with ¹⁴C-labelled CO₂ (experiment Q). Which ONE of the following options lists the first labelled products in experiments P and Q, respectively?

(A) P : O₂ Q : 3-phosphoglycerate

(B) P : 3-phosphoglycerate Q : NADPH

(C) P : O₂ Q : ATP

(D) P : 3-phosphoglycerate Q : 3-phosphoglycerate

A
(A)

B
(B)

C
(C)

D
(D)