नीचे दो कथन दिए गए हैं, एक को अभिकथन (A) और दूसरे को कारण (R) के...

सभी विषय सामान्य कृषि, फसल उत्पादन एवं मृदा विज्ञान कोशिका विज्ञान, आनुवंशिकी, कार्यिकी, जैव रसायन एवं पादप सुरक्षा आनुवंशिकी, पादप रोग विज्ञान, बीज विज्ञान एवं कृषि सूक्ष्मजीव विज्ञान खाद्य व औद्योगिक सूक्ष्मजीव विज्ञान, ग्रामीण विकास एवं कृषि अनुसंधान संरचना

Q.101

ICAR AIEEA PG 2024 - Plant Sciences

MCQ (Single Correct) +4 −1

Which of the following is NOT a serious limitation for conserving the plant genetic resources under in-vitro repositories?

इन-विट्रो रिपॉजिटरी (in-vitro repositories / ऊतक संवर्धन जीनबैंक) के तहत पादप आनुवंशिक संसाधनों के संरक्षण के लिए

निम्नलिखित में से कौन सी एक गंभीर सीमा (limitation) नहीं है?

Genetic stability may be compromised over time due to accumulation of somaclonal variations सोमाक्लोनल विविधताओं के संचय के कारण समय के साथ आनुवंशिक स्थिरता से समझौता हो सकता है High cost associated with establishment and maintenance of in-vitro collections इन-विट्रो संग्रह की स्थापना और रखरखाव से जुड़ी उच्च लागत Limited capacity to conserve large collections compared to field genebanks फील्ड जीनबैंक की तुलना में बड़े संग्रह को संरक्षित करने की सीमित क्षमता Vulnerability to catastrophic events such as power outages or equipment failure बिजली गुल होने या उपकरण की विफलता जैसी विनाशकारी घटनाओं के प्रति संवेदनशीलता

In-vitro Repositories for Plant Genetic Resources:

In-vitro repositories maintain slow-growth tissue cultures (meristems, shoot tips) under reduced temperature and light to conserve vegetatively propagated and recalcitrant crop species (potato, banana, cassava, yam).
Advantages of In-vitro Genebanks:
Extremely high storage capacity per unit space: Thousands of clonal accessions can be preserved in miniature culture test tubes on a few laboratory shelves, occupying hundreds of times less space than sprawling field genebanks. Thus, having 'limited capacity compared to field genebanks' is completely FALSE (it is actually a major strength, not a limitation).
True Limitations of In-vitro Conservation:
Somaclonal variation and genetic instability during repeated subcultures (1).
Expensive culture facilities, laminar hoods, and autoclaving costs (2).
Total dependency on uninterrupted electrical power and HVAC equipment (4).

Therefore, Option 3 is NOT a limitation. Correct Answer: Option 3.

विस्तृत व्याख्या:

In-vitro Repositories for Plant Genetic Resources (इन-विट्रो जीनबैंक):

In-vitro repositories maintain slow-growth tissue cultures (meristems, shoot tips) under reduced temperature and light to conserve vegetatively propagated and recalcitrant crop species (potato, banana, cassava, yam).
Advantages of In-vitro Genebanks:
Extremely high storage capacity per unit space: Thousands of clonal accessions can be preserved in miniature culture test tubes on a few laboratory shelves, occupying hundreds of times less space than sprawling field genebanks. Thus, having 'limited capacity compared to field genebanks' is completely FALSE (it is actually a major strength, not a limitation).
True Limitations of In-vitro Conservation:
Somaclonal variation and genetic instability during repeated subcultures (1).
Expensive culture facilities, laminar hoods, and autoclaving costs (2).
Total dependency on uninterrupted electrical power and HVAC equipment (4).

Therefore, Option 3 is NOT a limitation. Correct Answer: Option 3.

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report

Q.102

ICAR AIEEA PG 2024 - Plant Sciences

MCQ (Single Correct) +4 −1

The chasmogamy in plants is best described as-

पौधों में चैस्मोगैमी (Chasmogamy / उन्मील परागण) का सबसे अच्छा वर्णन किस रूप में किया जाता है?

The condition in which flowers remain closed during the day and open at night वह स्थिति जिसमें फूल दिन में बंद रहते हैं और रात में खुलते हैं The condition in which flowers open only after they have been pollinated वह स्थिति जिसमें फूल परागित होने के बाद ही खुलते हैं The condition in which flowers fail to open and misses self pollination वह स्थिति जिसमें फूल खुलने में विफल रहते हैं और स्व-परागण छूट जाता है The condition in which flowers are pollinated by wind instead of insects वह स्थिति जिसमें फूलों का परागण कीटों के बजाय हवा द्वारा होता है

Chasmogamy and Floral Biology in Crop Plants:

Cleistogamy: Flowers never open, strictly ensuring 100% self-pollination within closed petals (e.g., Commelina, subterranean flowers of peanut).
Chasmogamy: Flowers open exposing their reproductive organs to the atmosphere.
In many autogamous field crops (such as wheat, barley, and rice), anthesis exhibits a specialized chasmogamous behavior where anthers dehisce and self-pollinate the stigma while the glumes/florets are still closed, and flowers open only after self-pollination has already occurred (preventing outcrossing while allowing exhausted anthers to be extruded).
Official Answer Key: Option 2 represents the accepted NTA definition in agricultural crop breeding context.

Correct Answer: Option 2.

विस्तृत व्याख्या:

Chasmogamy and Floral Biology in Crop Plants (चैस्मोगैमी एवं पुष्प कार्यिकी):

Cleistogamy (क्लिस्टोगैमी / अनुन्मील परागण): Flowers never open, strictly ensuring 100% self-pollination within closed petals (e.g., Commelina, subterranean flowers of peanut).
Chasmogamy (चैस्मोगैमी / उन्मील परागण): Flowers open exposing their reproductive organs to the atmosphere.
In many autogamous field crops (such as wheat, barley, and rice), anthesis exhibits a specialized chasmogamous behavior where anthers dehisce and self-pollinate the stigma while the glumes/florets are still closed, and flowers open only after self-pollination has already occurred (preventing outcrossing while allowing exhausted anthers to be extruded).
Official Answer Key: Option 2 represents the accepted NTA definition in agricultural crop breeding context.

Correct Answer: Option 2.

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report

Q.103

ICAR AIEEA PG 2024 - Plant Sciences

MCQ (Single Correct) +4 −1

Which of the following is a term for a plant or an embryo that contains only a gametic chromosome set?

उस पौधे या भ्रूण के लिए कौन सा शब्द प्रयुक्त होता है जिसमें केवल युग्मक गुणसूत्र समुच्चय (gametic chromosome set) होता है?

Monoploid मोनोप्लॉयड (एकगुणी) Aneuploid असुगुणी Haploid अगुणित Gametophyte युग्मकोद्भिद

Q.104

ICAR AIEEA PG 2024 - Plant Sciences

Assertion & Reason +4 −1

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

Assertion (A) : During meiosis, genetic recombination occurs which leads to genetic diversity among offspring.

Reason (R) : Genetic recombination is facilitated by the crossing over of homologous chromosomes during prophase I of meiosis.

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

नीचे दो कथन दिए गए हैं, एक को अभिकथन (A) और दूसरे को कारण (R) के रूप में लेबल किया गया है:

अभिकथन (A) : अर्धसूत्रीविभाजन (meiosis) के दौरान, आनुवंशिक पुनर्संयोजन (genetic recombination) होता है जो संतानों में आनुवंशिक विविधता की ओर ले जाता है।

कारण (R) : आनुवंशिक पुनर्संयोजन अर्धसूत्रीविभाजन के प्रोफेज I (पूर्वावस्था I) के दौरान समजात गुणसूत्रों के विनिमय (crossing over) द्वारा सुगम होता है।

उपरोक्त कथनों के आलोक में, नीचे दिए गए विकल्पों में से सबसे उपयुक्त उत्तर चुनिए:

Both (A) and (R) are correct and (R) is the correct explanation of (A) (A) और (R) दोनों सही हैं और (R), (A) की सही व्याख्या है Both (A) and (R) are correct but (R) is NOT the correct explanation of (A) (A) और (R) दोनों सही हैं लेकिन (R), (A) की सही व्याख्या नहीं है (A) is correct but (R) is not correct (A) सही है लेकिन (R) सही नहीं है (A) is not correct but (R) is correct (A) सही नहीं है लेकिन (R) सही है

Meiotic Crossing Over and Genetic Recombination:

Assertion (A) is CORRECT: Sexual reproduction generates vast novel combinations of maternal and paternal alleles in offspring due to meiotic genetic recombination and independent assortment.
Reason (R) is CORRECT and correctly explains (A): During the pachytene stage of Prophase I of meiosis, homologous chromosomes pair closely (synapsis) to form tetrads. Non-sister chromatids undergo physical reciprocal exchange of genetic segments mediated by the synaptonemal complex and recombinase enzymes (crossing over), creating novel recombinant chromatids containing new combinations of alleles that directly produce genetic diversity in gametes.

Therefore, both (A) and (R) are correct and (R) is the correct explanation of (A). Correct Answer: Option 1.

विस्तृत व्याख्या:

Meiotic Crossing Over and Genetic Recombination (अर्धसूत्रीविभाजन एवं जीन विनिमय):

Assertion (A) is CORRECT: Sexual reproduction generates vast novel combinations of maternal and paternal alleles in offspring due to meiotic genetic recombination and independent assortment.
Reason (R) is CORRECT and correctly explains (A): During the pachytene stage of Prophase I of meiosis, homologous chromosomes pair closely (synapsis) to form tetrads. Non-sister chromatids undergo physical reciprocal exchange of genetic segments mediated by the synaptonemal complex and recombinase enzymes (crossing over), creating novel recombinant chromatids containing new combinations of alleles that directly produce genetic diversity in gametes.

Therefore, both (A) and (R) are correct and (R) is the correct explanation of (A). Correct Answer: Option 1.

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report

Q.105

ICAR AIEEA PG 2024 - Plant Sciences

Assertion & Reason +4 −1

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

Assertion (A) : In eukaryotic cells, the newly synthesized polypeptide chain is often modified after translation.

Reason (R) : Post-translational modifications such as phosphorylation, glycosylation, and cleavage may occur to the polypeptide chain to attain its functional form.

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

अभिकथन (A) : यूकेरियोटिक कोशिकाओं में, नव-संश्लेषित पॉलीपेप्टाइड श्रृंखला को अनुवाद (translation) के बाद अक्सर संशोधित किया जाता है।

कारण (R) : पॉलीपेप्टाइड श्रृंखला को अपने कार्यात्मक रूप को प्राप्त करने के लिए फॉस्फोराइलेशन, ग्लाइकोसिलेशन और प्रोटियोलिटिक विखंडन जैसे पश्च-अनुवाद संशोधन (PTMs) हो सकते हैं।

Post-Translational Modifications (PTMs) in Eukaryotes:

Assertion (A) is CORRECT: In eukaryotic cells, newly translated polypeptides emerging from ribosomes are frequently inactive precursor pro-proteins requiring chemical maturation.
Reason (R) is CORRECT and correctly explains (A): Essential biochemical transformations occur in the endoplasmic reticulum and Golgi apparatus:
Phosphorylation: Addition of phosphate groups by protein kinases to activate/deactivate catalytic domains.
Glycosylation: Covalent attachment of oligosaccharide chains essential for cell targeting, conformation, and stability.
Proteolytic Cleavage: Removal of inhibitory signal peptides or pro-domains (e.g., conversion of proinsulin to active insulin).
These modifications are necessary for the polypeptide to achieve its native tertiary/quaternary active conformation and functional form.

Therefore, both (A) and (R) are correct and (R) is the correct explanation of (A). Correct Answer: Option 1.

विस्तृत व्याख्या:

Post-Translational Modifications (PTMs) in Eukaryotes (पश्च-अनुवाद संशोधन):

Assertion (A) is CORRECT: In eukaryotic cells, newly translated polypeptides emerging from ribosomes are frequently inactive precursor pro-proteins requiring chemical maturation.
Reason (R) is CORRECT and correctly explains (A): Essential biochemical transformations occur in the endoplasmic reticulum and Golgi apparatus:
Phosphorylation: Addition of phosphate groups by protein kinases to activate/deactivate catalytic domains.
Glycosylation: Covalent attachment of oligosaccharide chains essential for cell targeting, conformation, and stability.
Proteolytic Cleavage: Removal of inhibitory signal peptides or pro-domains (e.g., conversion of proinsulin to active insulin).
These modifications are necessary for the polypeptide to achieve its native tertiary/quaternary active conformation and functional form.

Therefore, both (A) and (R) are correct and (R) is the correct explanation of (A). Correct Answer: Option 1.

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report