ICAR JRF Plant Science Practice Series Memory Based 2024 (Module 1) (41 – 80 MCQ) 

 

 

Question 41

Match List I with List II (Sex index and Sexual phenotype):

List I	List II
A. 1.0	I. Male
B. 0.5	II. Intersex
C. 0.67	III. Super male
D. 0.33	IV. Female

 

Options:

1. A-IV, B-I, C-II, D-III
2. A-IV, B-I, C-III, D-II
3. A-IV, B-III, C-I, D-II
4. A-I, B-IV, C-II, D-III

Correct Answer: 2

 

Explanation:

• This concept comes from Drosophila sex determination based on the X chromosome to autosome (X:A) ratio.
• Sex index = Number of X chromosomes / Number of sets of autosomes.
• A. 1.0 → X:A = 1 → Female (IV) → A-IV
• B. 0.5 → X:A = 0.5 → Male (I) → B-I
• C. 0.67 → X:A = 0.67 → Intersex (III) → C-III
• D. 0.33 → X:A = 0.33 → Super male (II) → D-II
• Therefore, correct matching is A-IV, B-I, C-III, D-II → Option 2.

 

 

 

Question 42

Match List I with List II (Objectionable weed and Crop):

List I	List II
A. Argemone mexicana	I. Lucerne
B. Johnson grass	II. Rapeseed and mustard
C. Cichorium intybus	III. Sorghum
D. Phalaris minor	IV. Wheat

 

Options:

1. A-II, B-III, C-IV, D-I
2. A-II, B-III, C-I, D-IV
3. A-II, B-I, C-III, D-IV
4. A-IV, B-III, C-I, D-II

Correct Answer: 2

 

• Explanation:
• Argemone mexicana (Mexican prickly poppy) is a common weed in rapeseed and mustard fields. Its seeds contaminate mustard seeds and can cause epidemic dropsy due to toxic alkaloids. → A-II
• Johnson grass (Sorghum halepense) is a perennial grass weed that infests sorghum fields. It is a close relative of cultivated sorghum and can act as a host for pathogens like sorghum mosaic virus. → B-III
• Cichorium intybus (chicory) is an objectionable weed in lucerne (alfalfa) seed production. Its seeds resemble lucerne seeds and are difficult to separate. → C-I
• Phalaris minor (canary grass) is a major weed in wheat fields, especially in the Indo-Gangetic plains. It is resistant to many herbicides. → D-IV
• Therefore, correct matching is A-II, B-III, C-I, D-IV → Option 2.

 

 

Question 43

Match List I with List II (Types of hybrid and Parental combinations):

List I	List II
A. Three way cross hybrid	I. (Inbred A x Inbred B) x Open pollinated variety
B. Modified single cross hybrid	II. Inbred A x Open pollinated variety
C. Double top-cross hybrid	III. (Inbred A x Inbred B) x Inbred C
D. Top cross hybrid	IV. (Inbred A x A*) x Inbred B

 

Options:

1. A-III, B-IV, C-II, D-I
2. A-III, B-I, C-IV, D-II
3. A-III, B-IV, C-I, D-II
4. A-I, B-IV, C-III, D-II

Correct Answer: 3

 

• Explanation:
• Three way cross hybrid (A) → Produced by crossing a single cross hybrid with an inbred line: (Inbred A × Inbred B) × Inbred C → A-III
• Modified single cross hybrid (B) → A modified version where one parent is a single cross hybrid and the other is an inbred: (Inbred A × A*) × Inbred B → B-IV
• Double top-cross hybrid (C) → A single cross hybrid is crossed with an open pollinated variety (OPV): (Inbred A × Inbred B) × OPV → C-I
• Top cross hybrid (D) → An inbred line is crossed with an open pollinated variety: Inbred A × OPV → D-II
• Therefore, correct matching is A-III, B-IV, C-I, D-II → Option 3.

 

 

 

Question 44

Match List I with List II (Particular item and Description):

List I	List II
A. Arboretum	I. Biogeographic region with higher biodiversity
B. Herbarium	II. Sum total of genes of a species
C. Biodiversity hotspot	III. Botanical garden with trees and shrubs
D. Germplasm	IV. Collection of dried leaf specimen

 

Options:

1. A-III, B-IV, C-I, D-II
2. A-III, B-IV, C-II, D-I
3. A-III, B-I, C-II, D-IV
4. A-IV, B-III, C-I, D-II

Correct Answer: 1

 

Explanation:

• Arboretum (A) → A botanical garden dedicated to the collection and display of trees and shrubs for study, conservation, and education. → A-III
• Herbarium (B) → A collection of preserved (dried) plant specimens mounted on sheets, used for taxonomic research and reference. → B-IV
• Biodiversity hotspot (C) → A biogeographic region characterized by high species richness and a high level of endemism, also threatened by human activity. → C-I
• Germplasm (D) → The total sum of genetic material (genes) present in a species or population, including cultivated varieties, wild relatives, and landraces. → D-II
• Therefore, correct matching is A-III, B-IV, C-I, D-II → Option 1.

 

 

Question 45

Match List I with List II (Crop and Ploidy level):

List I	List II
A. Rice	I. Tetraploid
B. Bread wheat	II. Triploid
C. Durum wheat	III. Diploid
D. Seedless banana	IV. Hexaploid

 

Options:

1. A-II, B-I, C-IV, D-III
2. A-III, B-IV, C-I, D-II
3. A-IV, B-I, C-II, D-III
4. A-I, B-IV, C-II, D-III

Correct Answer: 2

• Rice → diploid (2n = 24)
• Bread wheat → hexaploid (6n = 42)
• Durum wheat → tetraploid (4n = 28)
• Banana → triploid (3n) Ploidy level affects fertility, adaptability, and breeding behavior

 

Explanation:

• Rice (A) → Oryza sativa is a diploid (2n = 24) → A-III
• Bread wheat (B) → Triticum aestivum is a hexaploid (2n = 6x = 42) → B-IV
• Durum wheat (C) → Triticum durum is a tetraploid (2n = 4x = 28) → C-I
• Seedless banana (D) → Commercial edible bananas are triploid (3n) → D-II
• Therefore, correct matching is A-III, B-IV, C-I, D-II → Option 2.

 

 

Question 46

Match List I with List II (ICAR institute and Location of HQ):

List I	List II
A. Indian Institute of Maize Research	I. Karnal
B. National Institute of Abiotic Stress Management	II. Hyderabad
C. Indian Institute of Rice Research	III. Ludhiana
D. Indian Institute of Wheat and Barley Research	IV. Baramati

Options:

1. A-II, B-I, C-III, D-IV
2. A-III, B-IV, C-II, D-I
3. A-III, B-II, C-IV, D-I
4. A-IV, B-I, C-II, D-III

Correct Answer: 2

 

Explanation:

• Indian Institute of Maize Research (A) → Located in Ludhiana, Punjab → A-III
• National Institute of Abiotic Stress Management (B) → Located in Baramati, Maharashtra → B-IV
• Indian Institute of Rice Research (C) → Located in Hyderabad, Telangana → C-II
• Indian Institute of Wheat and Barley Research (D) → Located in Karnal, Haryana → D-I
• Therefore, correct matching is A-III, B-IV, C-II, D-I → Option 2.

 

 

Question 47

Match List I with List II (International Institute and Major mandate crop):

List I	List II
A. ICRISAT	I. Wheat
B. IITA	II. Pigeonpea
C. CIAT	III. Cassava
D. CIMMYT	IV. Cowpea

Options:

1. A-II, B-IV, C-I, D-III
2. A-II, B-IV, C-III, D-I
3. A-IV, B-II, C-III, D-I
4. A-IV, B-I, C-III, D-II

Correct Answer: 2

• Explanation:

• ICRISAT (International Crops Research Institute for the Semi-Arid Tropics) → Mandate crops include pigeonpea, sorghum, pearl millet, chickpea, groundnut → A-II
• IITA (International Institute of Tropical Agriculture) → Mandate crops include cowpea, cassava, yam, maize, soybean → B-IV
• CIAT (International Center for Tropical Agriculture) → Mandate crops include cassava, common bean, tropical forages → C-III
• CIMMYT (International Maize and Wheat Improvement Center) → Mandate crops include wheat and maize → D-I
• Therefore, correct matching is A-II, B-IV, C-III, D-I → Option 2.

 

 

 

Question 48

Match List I with List II (Scientist and Significant contribution):

List I	List II
A. Hugo de Vries	I. Coined the term mitosis
B. W. Flemming	II. Semi-conservative mode of DNA replication
C. C. Stern	III. Mutation
D. M.S. Meselson and F.W. Stahl	IV. Cytological basis of crossing over in Drosophila

 

Options:

1. A-III, B-I, C-II, D-IV
2. A-II, B-I, C-II, D-IV
3. A-III, B-I, C-IV, D-II
4. A-III, B-II, C-I, D-IV

 

Correct Answer: 3

• Hugo de Vries (A) → Proposed the mutation theory of evolution (studied Oenothera) → A-III
• Walther Flemming (B) → German biologist who coined the term mitosis and described chromosome behavior during cell division → B-I
• Curt Stern (C) → Provided cytological evidence for crossing over in Drosophila melanogaster (1931) → C-IV
• Matthew Meselson and Franklin Stahl (D) → Demonstrated semi-conservative mode of DNA replication through the Meselson-Stahl experiment (1958) → D-II
• Therefore, correct matching is A-III, B-I, C-IV, D-II → Option 3.

 

 

Question 49

Which of the following is a fiber yielding plant?

1. Triticum aestivum
2. Gossypium hirsutum
3. Lens culinaris
4. Glycine max

 

Correct Answer: 2

• Gossypium hirsutum (Upland cotton) is a major fiber crop cultivated worldwide for textile production. It produces long, soft, and spinnable fibers (trichomes) from the seed coat.
• Triticum aestivum (bread wheat) is a cereal grain crop used for food (flour, bread, etc.), not for fiber.
• Lens culinaris (lentil) is a pulse (legume) crop grown for its edible seeds, rich in protein.
• Glycine max (soybean) is an oilseed and pulse crop, used for oil extraction, animal feed, and food products, not for fiber.
• Thus, among the given options, only Gossypium hirsutum is a commercially important fiber-yielding plant.

 

 

Question 50

Given below are two statements, one is labelled as Assertion (A) and the other as Reason (R).

• Assertion (A): The International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA) establishes a multilateral system for facilitated access to a list of crop genetic resources (Annex I crops).
• Reason (R): The multilateral system applies to all plant species, including those not used for food or agriculture, to ensure global biodiversity conservation.

In light of the above statements, choose the correct answer from the options given below:

1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true but (R) is NOT the correct explanation of (A).
3. (A) is true but (R) is false.
4. (A) is false but (R) is true.

Correct Answer: 3

 

Explanation:

• Assertion (A) is true:ITPGRFA establishes a multilateral system for facilitated access to the genetic resources of 64 crops and forages listed in Annex I. This system promotes exchange and benefit-sharing.
• Reason (R) is false:The multilateral system does not apply to all plant species. It applies only to Annex I crops (those important for food and agriculture). Non-Annex I crops and non-agricultural plant species are not covered under the multilateral system.
• Therefore, (A) is true but (R) is false.

 

 

Question 51

The acronym ITPGRFA stands for:

1. International Trade on Plant Genetic Resources for Food and Agriculture
2. International Treaty on Plant Genetic Resources for Food and Agriculture
3. International Trade on Plant Genomic Resources for Food and Agriculture
4. International Treaty on Plant Genomic Resources for Food and Agriculture

Correct Answer: 2

 

Explanation:

• ITPGRFA stands for the International Treaty on Plant Genetic Resources for Food and Agriculture.
• It was adopted by the FAO (Food and Agriculture Organization) in 2001 and came into force in 2004.
• The treaty aims to:
  • Conserve plant genetic resources for food and agriculture.
  • Promote sustainable use of these resources.
  • Ensure fair and equitable sharing of benefits arising from their use.
• It establishes a Multilateral System for facilitated access to a list of 64 crops and forages (Annex I crops) for research, breeding, and training.
• The treaty recognizes Farmers’ Rights to save, use, exchange, and sell farm-saved seeds.
• Options using “Trade” or “Genomic” are incorrect because the treaty focuses on genetic resources (not trade or genomics) and is a Treaty (not a Trade agreement).

 

 

Question 52

• Assertion (A) is true:ITPGRFA establishes a multilateral system for facilitated access to the genetic resources of 64 crops and forages listed in Annex I. This system promotes exchange and benefit-sharing.
• Reason (R) is false:The multilateral system does not apply to all plant species. It applies only to Annex I crops (those important for food and agriculture). Non-Annex I crops and non-agricultural plant species are not covered under the multilateral system.
• Therefore, (A) is true but (R) is false.

Which of the following represents the most dominant cropping sequence in the Indo-Gangetic plains of India during the kharif to rabi season?

1. Wheat – Barley – Oats
2. Rice – Wheat – Maize
3. Wheat – Pulses – Oilseeds
4. Rice – Wheat – Millets

Correct Answer: 2

 

Explanation:

• The Indo-Gangetic plains (covering states like Punjab, Haryana, Uttar Pradesh, Bihar, and West Bengal) have the most intensive and dominant cropping system as Rice (kharif) – Wheat (rabi).
• In many areas, maize is also included as a third crop in the sequence, especially in parts of Uttar Pradesh and Bihar, making Rice – Wheat – Maize a common and productive rotation.
• Option 1 (Wheat – Barley – Oats) is not dominant in the Indo-Gangetic plains; barley and oats are grown in smaller areas.
• Option 3 (Wheat – Pulses – Oilseeds) is practiced but not the most dominant sequence.
• Option 4 (Rice – Wheat – Millets) is less common because millets are typically grown in drier regions (e.g., Rajasthan, Madhya Pradesh), not as a third crop in the intensive rice-wheat system.
• Thus, Rice – Wheat – Maize is the most dominant cropping sequence in the Indo-Gangetic plains.

 

 

Question 53

Seed coat is derived from:

1. Nucleus
2. Embryo
3. Endosperm
4. Testa

Correct Answer: DROPPED 

 

Explanation:

• The seed coat (also called testa) develops from the integuments of the ovule after fertilization.
• The integuments are protective layers surrounding the nucellus of the ovule.
• After fertilization, the integuments undergo differentiation and thickening to form the seed coat (testa).
• Option 4 says “Testa” – but testa is the seed coat itself, not the structure from which it is derived. The question asks “derived from”, so the correct answer should be integuments, which is not listed among the options.
• Nucleus (Option 1) – gives rise to the endosperm (in angiosperms) or is part of the female gametophyte; not involved in seed coat formation.
• Embryo (Option 2) – develops from the zygote; does not form the seed coat.
• Endosperm (Option 3) – develops from triple fusion (central cell + sperm); provides nutrition to the embryo; does not form the seed coat.
• Testa (Option 4) – is the seed coat itself, not the precursor.
• Since the correct precursor “integuments” is missing, the question was dropped from evaluation.

 

 

Question 54

Statement I: ‘Import Permit’ is an official document needed to introduce in India any plant genetic resources from other countries.
Statement II: The ‘Import Permit’ is signed by the Director General, ICAR.
Options:

1. Both Statement I and Statement II are true
2. Both Statement I and Statement II are false
3. Statement I is true but Statement II is false
4. Statement I is false but Statement II is true

Correct Answer: 3

 

Explanation:

• Statement I is true: An Import Permit is required for the introduction of any plant genetic resources (seeds, planting material, etc.) into India from other countries. This is governed by the Plant Quarantine (Regulation of Import into India) Order, 2003, under the Destructive Insects and Pests Act, 1914.
• Statement II is false: The Import Permit is not signed by the Director General of ICAR. It is issued by the Plant Quarantine Authority under the Ministry of Agriculture and Farmers’ Welfare (specifically, the Plant Protection Advisor or authorized quarantine officers).
• Therefore, Statement I is true but Statement II is false → Option 3.

 

 

 

Question 55

Statement I: Growth regulators which control plant growth and development are called phytohormones.
Statement II: Apical meristems are responsible for growth in length of branches and roots.
Options:

1. Both Statement I and Statement II are true
2. Both Statement I and Statement II are false
3. Statement I is true but Statement II is false
4. Statement I is false but Statement II is true

Correct Answer: 1

Explanation:

• Statement I is true: Phytohormones (plant growth regulators) are organic compounds produced in small quantities that regulate plant growth, development, and responses to environmental stimuli (e.g., auxins, gibberellins, cytokinins, abscisic acid, ethylene).
• Statement II is true: Apical meristems are located at the tips of shoots and roots. They are responsible for primary growth (increase in length) of branches and roots through cell division and elongation.
• Therefore, both statements are true → Option 1.

 

 

Question 56

Statement I: National Bureau of Animal Genetic Resources is located at Karnal.
Statement II: National Bureau of Fish Genetic Resources is located at Chennai.
Options:

1. Both Statement I and Statement II are true
2. Both Statement I and Statement II are false
3. Statement I is true but Statement II is false
4. Statement I is false but Statement II is true

Correct Answer: 3 (NBAGR is at Karnal – true; NBFGR is at Lucknow, not Chennai – false)

Explanation:

• Statement I is true: The National Bureau of Animal Genetic Resources (NBAGR) is located at Karnal, Haryana. It conserves and characterizes livestock and poultry genetic resources of India.
• Statement II is false: The National Bureau of Fish Genetic Resources (NBFGR) is located at Lucknow, Uttar Pradesh (not Chennai). It is responsible for conservation and documentation of fish genetic resources.
• Therefore, Statement I is true but Statement II is false → Option 3.

 

 

Question 57

Statement I: Rafi Ahmad Kidwai Award is bestowed by CSIR to a scientist of repute for contribution in the field of agriculture.
Statement II: ICAR awards Punjab Rao Deshmukh Woman Agricultural Scientist Award annually.
Options:

1. Both Statement I and Statement II are true
2. Both Statement I and Statement II are false
3. Statement I is true but Statement II is false
4. Statement I is false but Statement II is true

Correct Answer: 4

Explanation:

• Statement I is false: The Rafi Ahmed Kidwai Award is given by the Indian Council of Agricultural Research (ICAR), not CSIR. It is awarded for outstanding research in agriculture and allied sciences.
• Statement II is true: The Punjabrao Deshmukh Woman Agricultural Scientist Award is indeed given by ICAR annually to recognize contributions of women scientists in agriculture.
• Therefore, Statement I is false but Statement II is true → Option 4.

 

 

Question 58

In sea urchin DNA, which is double stranded, 10% of the bases are shown to be cytosine (C). Based on this observation, the following were recorded:
A. Guanine (G) are 10%
B. Adenine (A) are 40%
C. Thymine (T) are 20%
D. Purines are 50%
E. Purine and pyrimidine are equal
Options:

1. A, B, C and D only
2. A, B, C and E only
3. A, B, D and E only
4. A, C, D and E only

Correct Answer: 3 (If C=10%, then G=10%, so A+T=80%, A=40%, T=40%; Purines= A+G=50%; Purine=Pyrimidine)

 

Explanation 

• According to Chargaff’s rules for double-stranded DNA:
  • A = T and G = C
  • Purines (A + G) = Pyrimidines (T + C)
• Given: C = 10% → G = 10% (A is correct)
• Total G + C = 20% → Remaining A + T = 80% → Since A = T, A = 40% and T = 40% (B is correct, C is incorrect because T is 40%, not 20%)
• Purines = A + G = 40% + 10% = 50% (D is correct)
• Purine = Pyrimidine (50% each) (E is correct)
• Therefore, A, B, D, E are correct → Option 3.

 

 

Question 59

Most of the energy in the cells is liberated by oxidation of carbohydrates when:
A. Pyruvic acid is converted into sugar
B. Pyruvic acid is converted into acetyl-CoA
C. Sugar is converted into pyruvic acid
D. Glucose is converted into alcohol and CO₂
E. Pyruvic acid is converted into CO₂ and H₂O
Options:

1. A and B only
2. B and C only
3. A and D only
4. E only

Correct Answer: 4 (Maximum energy is released in Kreb’s cycle when pyruvic acid is converted into CO₂ and H₂O)

 

Explanation:

• Maximum energy (ATP) from carbohydrate oxidation is released during the complete oxidation of pyruvic acid to CO₂ and H₂O in the Krebs cycle (citric acid cycle) and oxidative phosphorylation (electron transport chain).
• Glycolysis (sugar → pyruvic acid) produces only 2 ATP (net).
• Pyruvic acid → acetyl-CoA produces no ATP directly (produces NADH).
• Pyruvic acid → sugar (gluconeogenesis) consumes energy.
• Glucose → alcohol + CO₂ (fermentation) produces only 2 ATP.
• Therefore, most energy is liberated when pyruvic acid is converted into CO₂ and H₂O → Option 4 (E only).

 

 

Question 60

Options:

1. C, D and E only
2. E only
3. A and B only
4. C and D only

Correct Answer: 2

Explanation:

• The specific question text is missing from the document, but the answer key indicates Option 2 (E only).
• Based on the pattern, this likely refers to a process or component that is uniquely correct among the given statements.
• Without the full question, a detailed explanation cannot be provided. However, the answer key confirms Option 2.

 

 

Question 61

Most commonly used enzymes for DNA manipulation include the following:
A. Nucleases
B. Ligases
C. Polymerases
D. Kinases
E. Helicases
Options:

1. A, D and E only
2. B, D and E only
3. A, B and C only
4. C, D and E only

Correct Answer: 3

Explanation:

• In recombinant DNA technology and molecular biology, the most commonly used enzymes are:
  • Nucleases (A) – Restriction endonucleases cut DNA at specific sequences (e.g., EcoRI, HindIII).
  • Ligases (B) – DNA ligase joins DNA fragments together (e.g., T4 DNA ligase).
  • Polymerases (C) – DNA polymerases synthesize new DNA strands (e.g., Taq polymerase for PCR, DNA polymerase I for nick translation).
• Kinases (D) – Polynucleotide kinase is used for labeling 5′ ends with phosphate, but it is less commonly used than nucleases, ligases, and polymerases.
• Helicases (E) – Unwind DNA during replication but are not routinely used in standard DNA manipulation in vitro.
• Therefore, the most commonly used are A, B, and C → Option 3.

 

 

Question 62

Which of the following is a form of ex-situ conservation?
A. Gene banks
B. Tissue culture repositories
C. National parks
D. Biosphere reserves
E. Botanical gardens
Options:

1. A, B and E only
2. B, D and E only
3. C, D and E only
4. A, B and C only

Correct Answer: 1

Explanation:

• Ex-situ conservation means conservation of biological diversity outside their natural habitat.
• Gene banks (A) – Store seeds, pollen, tissue, or DNA under controlled conditions (ex-situ).
• Tissue culture repositories (B) – Maintain plant tissue cultures in vitro (ex-situ).
• Botanical gardens (E) – Grow and maintain living plant collections outside their natural range (ex-situ).
• National parks (C) – Protected areas within natural habitats → in-situ conservation.
• Biosphere reserves (D) – Designated areas for conservation within natural ecosystems → in-situ conservation.
• Therefore, ex-situ conservation includes A, B, and E → Option 1.

 

 

Question 63

Match List I with List II:

List I	List II
A. ICRISAT	I. London
B. Kew Botanical Garden	II. Chennai
C. National Biodiversity Authority	III. New Delhi
D. Protection of Plant Varieties and Farmers’ Rights Authority	IV. Patancheru

Options:

1. A-IV, B-I, C-II, D-III
2. A-III, B-IV, C-II, D-I
3. A-I, B-II, C-III, D-IV
4. A-IV, B-III, C-II, D-I

Correct Answer: 1

• Explanation:

• ICRISAT (A) → The International Crops Research Institute for the Semi-Arid Tropics is headquartered at Patancheru, Hyderabad, Telangana, India → A-IV
• Kew Botanical Garden (B) → The Royal Botanic Gardens, Kew is located in London, United Kingdom → B-I
• National Biodiversity Authority (C) → The NBA is located in Chennai, Tamil Nadu. It implements the Biological Diversity Act (2002) in India → C-II
• Protection of Plant Varieties and Farmers’ Rights Authority (D) → The PPV&FR Authority is headquartered in New Delhi. It administers the PPV&FR Act (2001) → D-III
• Therefore, correct matching is A-IV, B-I, C-II, D-III → Option 1.

 

Question 64

Match List I with List II:

List I	List II
A. Zeatin	I. Auxin
B. Picloram	II. Amino acid
C. Thiamine	III. Cytokinin
D. Glutamine	IV. Vitamin

Options:

1. A-I, B-III, C-IV, D-II
2. A-III, B-I, C-IV, D-II
3. A-II, B-I, C-III, D-IV
4. A-III, B-II, C-IV, D-I

Correct Answer: 2

Explanation:

• Zeatin (A) → A naturally occurring cytokinin (plant growth regulator) first isolated from maize endosperm → A-III
• Picloram (B) → A synthetic auxin-like herbicide used for broadleaf weed control. It mimics auxin (IAA) and causes uncontrolled growth → B-I
• Thiamine (C) → Vitamin B1 (an essential vitamin) involved in carbohydrate metabolism → C-IV
• Glutamine (D) → An amino acid involved in nitrogen metabolism and protein synthesis → D-II
• Therefore, correct matching is A-III, B-I, C-IV, D-II → Option 2.

 

 

Question 65 

Match List I with List II:

List I	List II
A. Discovery of human blood group	I. B. McClintock
B. Double helical model of DNA	II. Crick, Watson and Wilkins
C. Genetic improvement of Mexican wheat	III. K. Landsteiner
D. Mobile genetic elements in maize	IV. N. Borlaug

Options:

1. A-I, B-II, C-III, D-IV
2. A-II, B-I, C-III, D-IV
3. A-III, B-I, C-II, D-IV
4. A-III, B-II, C-IV, D-I

Correct Answer: 4

Explanation:

• Discovery of human blood group (A) → Karl Landsteiner discovered the ABO blood group system in 1901, for which he received the Nobel Prize → A-III
• Double helical model of DNA (B) → James Watson, Francis Crick, and Maurice Wilkins proposed the double helix structure of DNA in 1953 (Nobel Prize 1962) → B-II
• Genetic improvement of Mexican wheat (C) → Norman Borlaug developed high-yielding, disease-resistant semi-dwarf wheat varieties (Green Revolution), Nobel Peace Prize 1970 → C-IV
• Mobile genetic elements in maize (D) → Barbara McClintock discovered transposons (jumping genes) in maize in the 1940s (Nobel Prize 1983) → D-I
• Therefore, correct matching is A-III, B-II, C-IV, D-I → Option 4.

 

 

Question 66

Match List I with List II (The options for List II are not fully visible, but the correct answer is given):

Options:

1. A-I, B-II, C-III, D-IV
2. A-IV, B-II, C-III, D-I
3. A-I, B-III, C-II, D-IV
4. A-IV, B-III, C-II, D-I

Correct Answer: 2

Explanation:

• Although the full matching lists are not visible in the document, the answer key indicates Option 2 (A-IV, B-II, C-III, D-I) is correct.
• The topic likely relates to biological associations or matching of scientists with discoveries, based on the pattern of other questions.
• Without the complete question text, a detailed explanation cannot be provided, but the answer key confirms Option 2.

 

 

Question 67 

Match List I with List II:

List I	List II
A. Protogyny	I. Differential maturation of male and female flowers
B. Androgyny	II. Stamen matures before pistil
C. Dichogamy	III. Pistil matures before stamen
D. Cleistogamy	IV. Flower does not open

Options:

1. A-I, B-II, C-IV, D-III
2. A-III, B-II, C-I, D-IV
3. A-III, B-I, C-II, D-IV
4. A-II, B-III, C-IV, D-I

Correct Answer: 2

 

Explanation:

• Protogyny (A) → The pistil (female part) matures before the stamen (male part). This promotes outcrossing by preventing self-pollination → A-III
• Androgyny (B) → The stamen matures before the pistil (also called protandry). This is another mechanism promoting outcrossing → B-II
• Dichogamy (C) → The differential (different) maturation of male and female flowers/organs. This is the general term that includes both protogyny and protandry → C-I
• Cleistogamy (D) → The flower does not open; self-pollination occurs within the closed flower. This ensures complete self-pollination → D-IV
• Therefore, correct matching is A-III, B-II, C-I, D-IV → Option 2.

 

 

Question 68 

Match List I with List II:

List I	List II
A. Rice	I. GMO hybrid
B. Tobacco	II. GMO for shelf life
C. Tomato	III. GMO for vitamin A
D. Cotton	IV. First GMO

Options:

1. A-III, B-IV, C-II, D-I
2. A-IV, B-II, C-I, D-III
3. A-II, B-I, C-III, D-IV
4. A-II, B-III, C-IV, D-I

Correct Answer: 1

• Explanation:
• Rice (A) → Golden Rice is genetically modified to produce β-carotene (vitamin A precursor) to address vitamin A deficiency → A-III
• Tobacco (B) → Was the first genetically modified (GMO) plant produced in 1983 (engineered for antibiotic resistance) → B-IV
• Tomato (C) → Flavr Savr tomato was the first commercially approved GMO for improved shelf life (delayed ripening by antisense RNA technology) → C-II
• Cotton (D) → Bt cotton is a GMO hybrid containing Bacillus thuringiensis genes for insect resistance (bollworm control) → D-I
• Therefore, correct matching is A-III, B-IV, C-II, D-I → Option 1.

 

 

 

Question 69 

Match List I with List II:

List I	List II
A. Grow-out test	I. Test for vigour of the seed
B. Osmotic stress test	II. Test for genetic purity of seed
C. Viability test	III. Test for aliveness of seed
D. Brick gravel test	IV. Test using PEG and mannitol

Options:

1. A-III, B-IV, C-II, D-I
2. A-IV, B-II, C-I, D-III
3. A-II, B-IV, C-III, D-I
4. A-IV, B-III, C-II, D-I

Correct Answer: 3

• Explanation:
• Grow-out test (A) → Used to verify genetic purity of a seed lot by growing plants and observing their morphological characteristics. → A-II
• Osmotic stress test (B) → Uses PEG (polyethylene glycol) or mannitol to create osmotic stress, simulating drought conditions to test seed vigor and germination under stress. → B-IV
• Viability test (C) → Determines whether seeds are alive or dead (e.g., tetrazolium test). → C-III
• Brick gravel test (D) → A physical test for seed vigor, where seeds are mixed with brick gravel and shaken to assess resistance to mechanical damage. → D-I
• Thus, the correct matching is A-II, B-IV, C-III, D-I → Option 3.

 

 

 

Question 70 

Assertion A: In the Watson-Crick model of DNA, each turn of the helix is the length of 10 base pairs.
Reason R: Each complete turn of the double-stranded DNA helix is 3.4 Å long.
Options:

1. Both A and R are correct and R is the correct explanation of A
2. Both A and R are correct but R is NOT the correct explanation of A
3. A is correct but R is not correct
4. A is not correct but R is correct

Correct Answer: 2 

• Explanation:
• Assertion (A) is correct: B-DNA has 10 base pairs per turn.
• Reason (R) is also correct: Each complete turn of DNA is 34 Å (3.4 nm), not 3.4 Å.
  • Correction: 3.4 Å is the rise per base pair, not per turn. One turn = 10 bp × 3.4 Å = 34 Å.
  • However, the question states “3.4 Å” which is factually incorrect. But the answer key says R is correct? This is likely a typo in the paper. In standard textbooks, one turn = 34 Å.
  • Despite this, the key says both are correct but R does not explain A. The number of base pairs per turn is a structural feature, while the helical length is a separate measurement. Knowing the length does not explain why there are 10 base pairs.
  • Therefore, both are considered correct, but R is not the correct explanation of A → Option 2.

 

 

Question 71

Assertion A: In DUS trials, the number and nature of varieties largely determines the use of experimental design.
Reason R: Randomized Incomplete Block Design is the most used experimental design in DUS trials.
Options:

1. Both A and R are correct and R is the correct explanation of A
2. Both A and R are correct but R is NOT the correct explanation of A
3. A is correct but R is not correct
4. A is not correct but R is correct

Correct Answer: 2

 

Explanation:

• Assertion (A) is correct: DUS (Distinctness, Uniformity, Stability) trials require experimental designs that can handle many varieties. The number and nature (e.g., grouped by maturity, plant type) influence the choice of design.
• Reason (R) is also correct: RIBD (Randomized Incomplete Block Design) is indeed commonly used in DUS trials, especially when the number of entries is large and complete blocks are impractical.
• However, R does not explain A. The fact that RIBD is commonly used does not explain why the number and nature of varieties determine the design choice. The design is chosen because of the number and nature, not the other way around.
• Therefore, both are correct but R is NOT the correct explanation of A → Option 2.

 

 

Question 72 

Assertion A: While alloinfection increases disease incidence, the autoinfection increases the disease severity.
Reason R: Neither autoinfection nor alloinfection is sufficient to cause disease epidemics.
Options:

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true but R is NOT the correct explanation of A
3. A is true but R is false
4. A is false but R is true

Correct Answer: 3

Explanation:

• Assertion (A) is true:
  • Alloinfection = infection from other plants (horizontal spread) → increases disease incidence (number of infected plants).
  • Autoinfection = infection from the same plant (vertical spread, e.g., secondary infections) → increases disease severity (intensity of disease on a single plant).
• Reason (R) is false: Epidemics are caused by both alloinfection and autoinfection working together. Alloinfection introduces the pathogen to new hosts, and autoinfection amplifies the inoculum, leading to rapid epidemic development. The statement “neither is sufficient” is incorrect; in fact, both contribute to epidemics.
• Therefore, A is true but R is false → Option 3.

 

 

Question 73 

Assertion A: Plant disease symptoms need not harbor the pathogen propagules always.
Reason R: Crown gall harbors Agrobacterium tumefaciens.
Options:

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true but R is NOT the correct explanation of A
3. A is true but R is false
4. A is false but R is true

Correct Answer: 2

 

• Explanation:
• Assertion (A) is true: Disease symptoms (e.g., mosaic, chlorosis, yellowing) can be observed even when visible pathogen structures (propagules) are not present. For example, viral symptoms may appear without visible fungal/bacterial structures.
• Reason (R) is also true: Crown gall disease, caused by Agrobacterium tumefaciens, does harbor the bacterium in the tumor tissue. This is a correct statement.
• However, R is just an example of a disease where pathogen propagules are present. It does not explain why symptoms need not always harbor propagules. The assertion is a general statement, while R is a specific counterexample (where propagules are present). R does not explain A.
• Therefore, both are true but R is NOT the correct explanation of A → Option 2.

 

 

Question 74 

Statement I: American grapevine root stock helped the French farmers to control root aphids.
Statement II: Root aphid resistant American root stock was also resistant to grapevine downy mildew.
Options:

1. Both Statement I and Statement II are correct
2. Both Statement I and Statement II are incorrect
3. Statement I is correct but Statement II is incorrect
4. Statement I is incorrect but Statement II is correct

Correct Answer: 3

 

Explanation:

• Statement I is correct: In the 19th century, the grapevine pest Phylloxera (a root aphid) devastated French vineyards. The solution was to graft European grapevines (Vitis vinifera) onto resistant American rootstocks (Vitis labrusca, Vitis riparia, etc.), which were resistant to Phylloxera.
• Statement II is incorrect: Resistance to root aphids (Phylloxera) is not the same as resistance to downy mildew (Plasmopara viticola). American rootstocks provided resistance to Phylloxera, but downy mildew is a different pathogen, and resistance to one does not confer resistance to the other. In fact, many American rootstocks are susceptible to downy mildew, requiring additional management.
• Therefore, Statement I is correct but Statement II is incorrect → Option 3.

 

 

Question 75 

Assertion A: Phytoplasma is a motile bacterium.
Reason R: Phytoplasma is transmitted by leaf hopper.
Options:

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true but R is NOT the correct explanation of A
3. A is true but R is false
4. A is false but R is true

Correct Answer: 4 (Phytoplasma is not motile; it is transmitted by leafhoppers)

 

Explanation:

• Assertion (A) is false: Phytoplasmas are wall-less bacteria belonging to the class Mollicutes. They lack flagella and are non-motile. They cannot move on their own.
• Reason (R) is true: Phytoplasmas are transmitted by leafhoppers (Cicadellidae) and also by planthoppers and psyllids. The vectors acquire phytoplasmas while feeding on infected plants and transmit them to healthy plants.
• Key distinction: Transmission by a vector does not imply motility. The vector actively moves and carries the pathogen passively. Phytoplasmas themselves are non-motile.
• Therefore, A is false but R is true → Option 4.

 

 

Question 76 

Statement I: Viruses are the only pathogens transmitted by nematodes.
Statement II: Biotic agents associated with plants are known to transmit plant pathogens.
Options:

1. Both Statement I and Statement II are correct
2. Both Statement I and Statement II are incorrect
3. Statement I is correct but Statement II is incorrect
4. Statement I is incorrect but Statement II is correct

Correct Answer: 4

 

Explanation:

• Statement I is incorrect: Nematodes are well-known vectors for plant viruses (e.g., Xiphinema, Longidorus, Trichodorus transmit nepoviruses and tobraviruses). However, nematodes can also transmit other pathogens:
  • Some nematodes transmit bacteria (e.g., Rathayibacter species by seed gall nematodes).
  • Fungal pathogens like Fusarium can be associated with nematode feeding wounds, though not strictly “transmitted” in the biological sense.
  • The statement “only pathogens” is exaggerated and false.
• Statement II is correct: Biotic agents (insects, mites, nematodes, fungi, etc.) associated with plants are known to transmit plant pathogens (viruses, bacteria, fungi, phytoplasmas). This is the concept of vectors in plant pathology.
• Therefore, Statement I is incorrect but Statement II is correct → Option 4.

 

 

Question 77 

Assertion A: Antibiotics are sterilized by bacteriological filters but not by heat.
Reason R: Antibiotics are thermolabile compounds.
Options:

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true but R is NOT the correct explanation of A
3. A is true but R is false
4. A is false but R is true

 

Correct Answer: 1

• Assertion (A) is true: Antibiotics are sensitive to heat and cannot be sterilized by autoclaving or dry heat, as high temperatures degrade them. Instead, they are sterilized using bacteriological (membrane) filters (0.22 µm pore size) that remove microorganisms without damaging the antibiotic.
• Reason (R) is true: Antibiotics are thermolabile (heat-sensitive) compounds. Their chemical structure breaks down at high temperatures, rendering them ineffective.
• R correctly explains A: Because antibiotics are thermolabile (R), they cannot be heat-sterilized and must be filter-sterilized (A). The reason directly explains the assertion.
• Therefore, both are true and R is the correct explanation of A → Option 1.

 

 

Question 78 

Which of the following belong to Oomycetes?

1. Pestalotia
2. Phyllosticta
3. Plasmopara
4. Puccinia

Correct Answer: 3

Explanation:

• Oomycetes (water molds) are fungus-like organisms but belong to the kingdom Stramenopila (not true fungi). Key features:
  • Cell wall composed of cellulose (not chitin).
  • Hyphae are aseptate (coenocytic).
  • Asexual reproduction bybiflagellate zoospores (one tinsel, one whiplash).
  • Sexual reproduction by oospores.
  • Mostly aquatic or require high moisture.
• Plasmopara is a genus of Oomycetes causing downy mildew (e.g., Plasmopara viticola on grape, Plasmopara halstedii on sunflower).
• Pestalotia (now often classified as Pestalotiopsis) is a true fungus (Ascomycete), a plant pathogen causing leaf spots and fruit rots.
• Phyllosticta is a true fungus (Ascomycete), causing leaf spots on many plants.
• Puccinia is a true fungus (Basidiomycete), causing rust diseases on cereals and other plants.
• Thus, only Plasmopara belongs to Oomycetes → Option 3.

 

 

Question 79 

Options:

1. Fusarium oxysporum
2. Fusarium solani
3. Ralstonia solanacearum
4. Ralstonia pseudosolanacearum

Correct Answer: 3

Explanation:

• Ralstonia solanacearum is a bacterial plant pathogen causing bacterial wilt (also called brown rot) in over 200 plant species, including tomato, potato, eggplant, banana, and tobacco.
• Key features:
  • Gram-negative, aerobic, rod-shaped bacterium.
  • Enters through roots, colonizes the xylem vessels, and produces exopolysaccharides that block water transport.
  • Symptoms: Sudden wilting, leaves remain green, vascular browning, bacterial ooze from cut stems.
• Fusarium oxysporum (Option 1) is a fungal pathogen causing Fusarium wilt (vascular wilt) in many crops.
• Fusarium solani (Option 2) is a fungal pathogen causing root rot, stem rot, and fruit rot (e.g., in cucurbits, legumes).
• Ralstonia pseudosolanacearum (Option 4) is a closely related species, but the question expects the most common and widely known bacterial wilt pathogen, which is Ralstonia solanacearum.
• Thus, the correct answer is Ralstonia solanacearum → Option 3.

 

 

Question 80

Statement I: True fungi are typically terrestrial-adapted organisms.
Statement II: True fungi possess chitin in the cell wall.
Options:

1. Both Statement I and Statement II are correct
2. Both Statement I and Statement II are incorrect
3. Statement I is correct but Statement II is incorrect
4. Statement I is incorrect but Statement II is correct

Correct Answer: 1

 

Explanation:

• Statement I is correct: True fungi (Kingdom Fungi) are primarily terrestrial organisms, though some are found in freshwater or marine environments. They are adapted to living on land, decomposing organic matter, or forming symbiotic relationships with plants (mycorrhizae) and algae (lichens).
• Statement II is correct: True fungi have cell walls composed of chitin (a polysaccharide containing N-acetylglucosamine). This is a diagnostic feature that distinguishes true fungi from Oomycetes (which have cellulose-based cell walls).

• Comparison with Oomycetes:

• Therefore, both statements are correct → Option 1.