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NEET 2023 Botany Question 140 Solution

Topic: Respiration in Plants · Official NTA Booklet Code G5
NEET 2023 Botany Question 140: Respiratory Pathways and Key Catalytic Enzymes

Question

Match List I with List II. List I: A. Oxidative decarboxylation; B. Glycolysis; C. Oxidative phosphorylation; D. Tricarboxylic acid cycle. List II: I. Citrate synthase; II. Pyruvate dehydrogenase; III. Electron transport system; IV. EMP pathway. Choose the correct answer from the options given below:

✓
Verified Against NTA Final Answer Key
Option (1) : A-II, B-IV, C-III, D-I
📚 Respiration in Plants Easy
📋 Given Parameters & Problem Setup
List I (Pathways) Oxidative decarboxylation, Glycolysis, Oxidative phosphorylation, TCA cycle
List II (Components) Citrate synthase, Pyruvate dehydrogenase, ETS, EMP pathway
⚡

The 30-Second Exam Hall Shortcut: ⚡ Respiratory Pathway 1-to-1 Association Match

⏱️ Save ~25 seconds

Match each reaction to its textbook hallmark: Oxidative decarboxylation of pyruvate = Pyruvate dehydrogenase (II). Glycolysis = EMP pathway (IV). Oxidative phosphorylation = Electron transport system / ETS (III). TCA cycle = Citrate synthase (I)!

1 Oxidative decarboxylation: Pyruvate -> Acetyl CoA catalyzed by Pyruvate dehydrogenase -> A-II.
2 Glycolysis: EMP (Embden, Meyerhof, Parnas) pathway -> B-IV.
3 Oxidative phosphorylation: ATP synthesis coupled to Electron transport system (ETS) -> C-III.
4 Tricarboxylic acid cycle: First committed step catalyzed by Citrate synthase -> D-I.
5 Match combination: A-II, B-IV, C-III, D-I -> Option (1).
🛡️
Why You Can 100% Trust This Shortcut: Canonical NCERT Cellular Respiration pathway nomenclature and enzymology.
📐

Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Detailed Pathway Enzymology and Correlates

Analyzing the metabolic pairings in aerobic respiration:

A. Oxidative decarboxylation:Pyruvate+CoA+NAD+→Pyruvate dehydrogenaseAcetyl CoA+CO2+NADH  ⟹  IIB. Glycolysis:Embden-Meyerhof-Parnas pathway (EMP)  ⟹  IVC. Oxidative phosphorylation:Mitochondrial inner membrane Electron Transport System (ETS)  ⟹  IIID. Tricarboxylic acid cycle:Condensation of Acetyl CoA with OAA via Citrate synthase  ⟹  I\begin{aligned} \text{\textbf{A. Oxidative decarboxylation:}} & \quad \text{Pyruvate} + \text{CoA} + \text{NAD}^+ \xrightarrow{\mathbf{\text{Pyruvate dehydrogenase}}} \text{Acetyl CoA} + CO_2 + \text{NADH} \implies \mathbf{\text{II}} \\[4pt] \text{\textbf{B. Glycolysis:}} & \quad \text{Embden-Meyerhof-Parnas pathway (EMP)} \implies \mathbf{\text{IV}} \\[4pt] \text{\textbf{C. Oxidative phosphorylation:}} & \quad \text{Mitochondrial inner membrane Electron Transport System (ETS)} \implies \mathbf{\text{III}} \\[4pt] \text{\textbf{D. Tricarboxylic acid cycle:}} & \quad \text{Condensation of Acetyl CoA with OAA via } \mathbf{\text{Citrate synthase}} \implies \mathbf{\text{I}} \end{aligned}
Step 2

Option Cross-Verification

Matching A-II and B-IV immediately isolates Options (1) and (3). Checking C-III and D-I unambiguously confirms Option (1).

⭐

360° Option Elimination Engine Key Feature

Diagnose every choice: Know exactly why the right option works and why distractors fail.

4-Option Deep Scan
1 1
✓ 100% Correct
Verdict & Scientific Reason:

Every pairing accurately matches the canonical NCERT enzyme and pathway definitions.

💡
Why this is airtight: None; clean biochemical pairing.
2 2
✗ Incorrect
Verdict & Scientific Reason:

Mismatches oxidative decarboxylation with ETS.

⚠️
Student Fallacy (Why candidates pick this trap): Confusing terminal electron transfer with link reaction.
3 3
✗ Incorrect
Verdict & Scientific Reason:

Inverts Oxidative phosphorylation and TCA cycle.

⚠️
Student Fallacy (Why candidates pick this trap): Swapping Citrate synthase with Electron transport system.
4 4
✗ Incorrect
Verdict & Scientific Reason:

Completely scrambled matches across all 4 entries.

⚠️
Student Fallacy (Why candidates pick this trap): Guessing without tracking individual enzymatic reactions.
⚠️

NTA Trap Alert: Oxidative Decarboxylation vs. Phosphorylation Trap

Both terms begin with "Oxidative". Decarboxylation refers to loss of CO2CO_2 from pyruvate via pyruvate dehydrogenase; Phosphorylation refers to ATP synthesis via the ETS complex.

🛡️ How to avoid the -1 mark: Decarboxylation = releases CO2CO_2 (Pyruvate dehydrogenase). Phosphorylation = makes ATP (ETS).
📖

Core NEET Syllabus Standard

NCERT Biology · Respiration in Plants Standard Benchmark
Core Scientific Principle Tested:

"Pyruvate undergoes oxidative decarboxylation by pyruvate dehydrogenase; Glycolysis is EMP pathway; Oxidative phosphorylation occurs via ETS; TCA cycle begins with citrate synthase."

Syllabus Focus: Aerobic Respiration & Fermentation
✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

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