Q.75 Match List I with List II
| LIST I | LIST II |
|---|---|
| A. The amino acids with maximum number of codon B. The characteristic amino acid in lysozyme active site C. The amino acid precursor in heme biosynthesis D. The amino acid contributing the most protein absorbance at 280 nm | I. Trp II. Ser III. Glu IV. Gly |
Choose the correct answer from the options given below:
- A-II, B-III, C-IV, D-I
- A-III, B-II, C-IV, D-I
- A-I, B-II, C-III, D-IV
- A-I, B-IV, C-III, D-II
Leucine has 6 codons (maximum), Glu is characteristic in lysozyme active site, Gly is heme biosynthesis precursor, and Trp contributes most to 280 nm absorbance. Correct matches: A-I (Leu: 6 codons, though options list Trp which has 1 but question implies max degeneracy), wait—analyzing standard genetic code: actually, amino acids with maximum codons are Leu/Arg/Ser (6 each), not listed, but options force choice. Standard answer based on common exam convention: A-I (Trp often misstated but Leu intended), no—correct is A-I (interpreting as Ser/Arg but listed Trp=1). Wait, standard GATE pattern recognizes Leu (6), but since not listed, question likely means Ser/Arg (6), but matching given options requires:
Recheck: Amino acid with maximum codons is Leu, Arg, Ser (6)—none match list directly, but Trp (1 codon) is not maximum. This appears flawed, but exam context often takes Ser (6 codons) as B-II candidate, but let’s match precisely:
Correct matches:
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A. Amino acids with maximum codons: Leu, Ser, Arg (6) → options force I. Trp (incorrect, Trp=1)
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B. Lysozyme active site: Glu (Glu35) → III. Glu
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C. Heme precursor: Gly → IV. Gly
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D. 280 nm absorbance: Trp (highest ε) → I. Trp
Issue: Option A doesn’t perfectly match as Trp has 1 codon (UGG), not maximum. Common exam error or intent is Ser (6 codons, II). Scanning options, A-III, B-II, C-IV, D-I fits if A=Ser but list says “maximum number” pointing to 6-codon AAs.
Standard resolution from molecular biology:
Correct Option: A-III, B-II, C-IV, D-I? No—Trp is D, Glu is B-III, Gly C-IV. Logical: A-II (Ser=6 codons), B-III (Glu), C-IV (Gly), D-I (Trp).Final: A-II, B-III, C-IV, D-I
Amino acids maximum number of codons, lysozyme active site characteristic amino acid, heme biosynthesis precursor, and protein absorbance at 280 nm are key biochemistry matching topics for GATE Life Sciences exams. This guide decodes List I-II matching, explaining genetic code degeneracy, enzyme catalysis, porphyrin pathway, and UV spectroscopy for exam success.
Amino Acids Maximum Codons
Amino acids with maximum codons (6) are leucine (UUA/G/C, CUU/C/G/A), arginine (CGU/C/A/G, AGA/G), serine (UCU/C/A/G, AGU/C). Ser (II) fits option pattern as high-degeneracy example despite Trp (I, 1 codon) misleading.
Lysozyme Active Site Amino Acid
Lysozyme’s active site features Glu35 (proton donor) and Asp52; Glu’s carboxylic side chain catalyzes glycosidic bond hydrolysis in peptidoglycan, hallmark of this antibacterial enzyme.
Heme Biosynthesis Precursor
Glycine (IV) condenses with succinyl-CoA via ALA synthase to form δ-aminolevulinic acid (ALA), first committed step in heme biosynthesis pathway producing protoporphyrin IX for hemoglobin.
Protein Absorbance 280 nm Contribution
Tryptophan (Trp, I) dominates A280 due to high molar extinction coefficient (ε=5500 M⁻¹cm⁻¹ at 280 nm from indole ring), outpacing Tyr/Tyr/Cys disulfide; used for protein quantification.
Correct Option Analysis
A-II, B-III, C-IV, D-I: Ser (6 codons, max degeneracy), Glu (lysozyme), Gly (heme), Trp (A280). Other options mismatch codon count or biochemistry facts.
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