GATE XL year:2025 PYQs & Answers — Page 6

Questions 51–60 of 122. Imported answers require independent review unless marked reviewed.

Which one of the following agents causes the necrotic ring spot disease in stone fruits?

Your answerChoose one option.

Fungi

Bacteria

Virus

Nematodes

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Identify the correct statement(s) with respect to plant disease.

Your answerSelect all correct options. You can choose more than one.

Hairy root disease in tobacco is caused by Agrobacterium tumefaciens

Loose smut of barley is caused by Ustilago nuda

Stem rust of grape is caused by Plasmopara viticola

Fire blight in pear is caused by Erwinia amylovora

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Which of the following molecular approaches can be used to generate complete knock-out of a target gene in plants?

Your answerSelect all correct options. You can choose more than one.

Homologous recombination

CRISPR-Cas9

Antisense RNA technique

Activation tagging

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If an egg cell of a diploid plant species has 10 chromosomes, the expected number of chromosomes in a double trisomic somatic cell of this species would be ____________ (Answer in integer).

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In the history of photosynthetic research, the empirical reaction of photosynthesis was first proposed for green plants (equation 1), followed by another reaction for purple sulfur bacteria (equation 2), leading to a generalized equation for photosynthesis (equation 3)

where H₂A in equation 3 is a generalized electron donor.

Which one of the following statements is DISPROVEN by equation 3?

Your answerChoose one option.

The source of oxygen produced in photosynthesis in green plants is CO₂

The source of oxygen produced in photosynthesis in green plants is H₂O

Light is essential in every form of photosynthesis

Glucose is the end product in all forms of photosynthesis

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Consider a diploid plant species where the cells in the epidermis (the outermost single cell layer) always divide in the anticlinal orientation. If one such cell within the central zone of the shoot apical meristem (SAM) spontaneously becomes tetraploid at the seedling stage, which one of the following cellular arrangements would be most likely observed if the meristem is examined at the adult stage?

Your answerChoose one option.

Only one tetraploid cell in the epidermis

Many tetraploid cells in the epidermis

All cells in the entire SAM tetraploid

All cells in the entire SAM diploid

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Correctly match the photosynthetic pathways (Group I) with their first stable products (Group II) in respective plants (Group III)

Group I: (P) C3 cycle; (Q) C4 cycle; (R) CAM Group II: (1) 3-Phosphoglycerate; (2) Glyceraldehyde-3-phosphate; (3) Oxaloacetate Group III: (a) Wheat; (b) Sugarcane; (c) Pineapple

Your answerChoose one option.

P-1-a; Q-3-b; R-3-c

P-1-a; Q-2-b; R-3-c

P-1-b; Q-3-a; R-2-c

P-1-b; Q-2-c; R-2-a

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The following table summarizes the flowering time (days to flower) and the transcript levels in four genotypes of a plant species.

Genotype | Days to flower | Transcript level of gene A | Transcript level of gene B Wild type | 30 | Normal | Normal a mutant | 15 | Nil | Increased b mutant | 60 | Normal | Nil ab double mutant | 60 | Nil | Nil

Which one of the following genetic pathways best explains the observations shown in the table?

Your answerChoose one option.

A gene activates B, which suppresses flowering transition

A gene suppresses B, which promotes flowering transition

B gene activates A, which suppresses flowering transition

B gene suppresses A, which promotes flowering transition

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Correctly match the economically important specialized metabolites (Group I) with their broad chemical classes (Group II).

Group I: (P) Azadirachtin; (Q) Saponin; (R) Gallocatechin; (S) Cocaine; (T) Menthol Group II: (1) Monoterpene; (2) Alkaloid; (3) Triterpene glycoside; (4) Polyphenol; (5) Triterpene

Your answerChoose one option.

P-5; Q-3; R-2; S-4; T-1

P-2; Q-4; R-3; S-1; T-5

P-5; Q-3; R-4; S-2; T-1

P-3; Q-5; R-4; S-2; T-1

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Correctly match the following Arabidopsis genes (Group I) and the biological processes they primarily regulate (Group II).

Group I: (P) CLAVATA3; (Q) CONSTANS; (R) SCARECROW; (S) AGAMOUS. Group II: (1) Organ identity in flower; (2) Cell-type specification in root meristem; (3) Meristem size in shoot; (4) Photoperiodic floral transition

Your answerChoose one option.

P-3; Q-4; R-1; S-2

P-1; Q-3; R-2; S-4

P-3; Q-4; R-2; S-1

P-4; Q-1; R-3; S-2

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GATE XL year:2025 PYQs

Question 51

Question 52

Question 53

Question 54

Question 55

Question 56

Question 57

Question 58

Question 59

Question 60