Given below are two statements: Statement (I): The first amino...

Q.6

ICAR AIEEA PG 2024 - Plant Sciences (Q.72)

Assertion & Reason

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

Assertion (A) : During DNA replication, the lagging strand is replicated in short pieces.

Reason (R) : DNA polymerase can synthesize the DNA only in one direction i.e. 5' to 3'.

In light of the above statements, choose the correct 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) : डीएनए प्रतिकृति (DNA replication) के दौरान, पश्चगामी रज्जुक (lagging strand) छोटे टुकड़ों में प्रतिकृत होता है।

कारण (R) : डीएनए पोलीमरेज़ केवल एक ही दिशा में यानी 5' से 3' दिशा में डीएनए का संश्लेषण कर सकता है।

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

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

Mechanism of DNA Replication on Lagging Strand:

Assertion (A) is TRUE: During semiconservative DNA replication at the replication fork, the lagging strand is synthesized discontinuously as short segments known as Okazaki fragments (1,000–2,000 nucleotides in prokaryotes, 100–200 nucleotides in eukaryotes).
Reason (R) is TRUE: All known DNA polymerases possess strict catalytic polarity: they can only add free deoxyribonucleotides to an existing 3'-OH group, thus extending growing DNA chains exclusively in the 5' $\rightarrow$ 3' direction.
Official Answer Key Note: In the official NTA answer key, this question is keyed as Option 2 (Both (A) and (R) are true but (R) is NOT the correct explanation of (A)), emphasizing that the antiparallel orientation of parental DNA strands combined with unidirectional fork progression is additionally required to necessitate lagging strand discontinuity.

Correct Answer: Option 2.

विस्तृत व्याख्या:

Mechanism of DNA Replication on Lagging Strand (डीएनए प्रतिकृति एवं ओकाज़ाकी खंड):

Assertion (A) is TRUE: During semiconservative DNA replication at the replication fork, the lagging strand is synthesized discontinuously as short segments known as Okazaki fragments (1,000–2,000 nucleotides in prokaryotes, 100–200 nucleotides in eukaryotes).
Reason (R) is TRUE: All known DNA polymerases possess strict catalytic polarity: they can only add free deoxyribonucleotides to an existing 3'-OH group, thus extending growing DNA chains exclusively in the 5' $\rightarrow$ 3' direction.
Official Answer Key Note: In the official NTA answer key, this question is keyed as Option 2 (Both (A) and (R) are true but (R) is NOT the correct explanation of (A)), emphasizing that the antiparallel orientation of parental DNA strands combined with unidirectional fork progression is additionally required to necessitate lagging strand discontinuity.

Correct Answer: Option 2.

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

Q.7

ICAR AIEEA PG 2024 - Plant Sciences (Q.73)

MCQ (Single Correct)

In a DNA molecule, if 30% of the bases are adenine, what will be the percentage of cytosine bases?

एक डीएनए अणु में, यदि 30% क्षार एडेनिन (adenine) हैं, तो साइटोसिन (cytosine) क्षारों का प्रतिशत क्या होगा?

30% 30% 25% 25% 60% 60% 20% 20%

Q.8

ICAR AIEEA PG 2024 - Plant Sciences (Q.78)

Statement Based

Given below are two statements

Statement (I) : The first amino acid in protein synthesis is Methionine in Eubacteria.

Statement (II) : The first amino acid in protein synthesis is N-formyl-methionine in Archaea.

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

नीचे दो कथन दिए गए हैं

कथन (I) : यूबैक्टीरिया (Eubacteria) में प्रोटीन संश्लेषण में पहला अमीनो अम्ल मेथियोनीन (Methionine) होता है।

कथन (II) : आर्किया (Archaea) में प्रोटीन संश्लेषण में पहला अमीनो अम्ल N-फॉर्मिल-मेथियोनीन (fMet) होता है।

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

Both Statement (I) and Statement (II) are true कथन (I) और कथन (II) दोनों सत्य हैं Both Statement (I) and Statement (II) are false कथन (I) और कथन (II) दोनों असत्य हैं Statement (I) is true but Statement (II) is false कथन (I) सत्य है लेकिन कथन (II) असत्य है Statement (I) is false but Statement (II) is true कथन (I) असत्य है लेकिन कथन (II) सत्य है

Q.9

ICAR AIEEA PG 2024 - Plant Sciences (Q.88)

Statement Based

Given below are two statements

Statement (I) : Non-proteinaceous molecules associated with the enzymes are called cofactors.

Statement (II) : The cofactors can be a metal ion or an organic molecule.

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

नीचे दो कथन दिए गए हैं

कथन (I) : एंजाइमों से जुड़े गैर-प्रोटीनयुक्त अणुओं (non-proteinaceous molecules) को सहकारक (cofactors) कहा जाता है।

कथन (II) : सहकारक धातु आयन (metal ion) या एक कार्बनिक अणु (organic molecule) हो सकते हैं।

Both Statement (I) and Statement (II) are correct कथन (I) और कथन (II) दोनों सही हैं Both Statement (I) and Statement (II) are incorrect कथन (I) और कथन (II) दोनों गलत हैं Statement (I) is correct but Statement (II) is incorrect कथन (I) सही है लेकिन कथन (II) गलत है Statement (I) is incorrect but Statement (II) is correct कथन (I) गलत है लेकिन कथन (II) सही है

Enzyme Structure and Cofactors:

conjugated, catalytically active enzyme is called a holoenzyme, which consists of a protein component (apoenzyme) and a non-protein chemical component (cofactor).
Statement (I) is CORRECT: Non-proteinaceous molecules required for an enzyme's biological catalytic activity are designated as cofactors.
Statement (II) is CORRECT: Cofactors are broadly divided into two major groups:

Inorganic ions / metal ions: Such as $\text{Fe}^{2+}, \text{Mg}^{2+}, \text{Mn}^{2+}, \text{Zn}^{2+}$ (essential for DNA polymerase, alcohol dehydrogenase, etc.).
Organic molecules: Subdivided into coenzymes (transiently bound, e.g., NAD, FAD, CoA) and prosthetic groups (tightly/covalently bound, e.g., heme, biotin).

Therefore, both Statement (I) and Statement (II) are correct. Correct Answer: Option 1.

विस्तृत व्याख्या:

Enzyme Structure and Cofactors (एंजाइम एवं सहकारक):

conjugated, catalytically active enzyme is called a holoenzyme, which consists of a protein component (apoenzyme) and a non-protein chemical component (cofactor).
Statement (I) is CORRECT: Non-proteinaceous molecules required for an enzyme's biological catalytic activity are designated as cofactors.
Statement (II) is CORRECT: Cofactors are broadly divided into two major groups:

Inorganic ions / metal ions: Such as $\text{Fe}^{2+}, \text{Mg}^{2+}, \text{Mn}^{2+}, \text{Zn}^{2+}$ (essential for DNA polymerase, alcohol dehydrogenase, etc.).
Organic molecules: Subdivided into coenzymes (transiently bound, e.g., NAD, FAD, CoA) and prosthetic groups (tightly/covalently bound, e.g., heme, biotin).

Therefore, both Statement (I) and Statement (II) are correct. Correct Answer: Option 1.

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

Q.10

ICAR AIEEA PG 2024 - Plant Sciences (Q.89)

MCQ (Single Correct)

Who proposed 'Operon model' for gene regulation in bacteria?

जीवाणुओं में जीन नियमन (gene regulation) के लिए 'ऑपेरॉन मॉडल' (Operon model) किसने प्रस्तावित किया था?

Sanger सेंगर Watson and Crick वाटसन और क्रिक James and Monod जेम्स और मोनोड François Jacob & Jacques Monod जैकब और मोनोड (François Jacob & Jacques Monod)