Q.57 Given below are two statements :
Statement I :
Glycolysis involves a series of reactions carried out by group of soluble enzymes
located in both cytosol and plastid.
Statement II :
Pentose phosphate pathway is also located both in cytosol and plastid.
In the light of the above statements, choose the correct answer from the options given below :
- Both Statement I and Statement II are correct
- Both Statement I and Statement II are incorrect
- Statement I is correct but Statement II is incorrect
- Statement I is incorrect but Statement II is correct
Statement I is incorrect, but Statement II is correct, as glycolysis enzymes are cytosolic only (not plastids), while the pentose phosphate pathway operates in both cytosol and plastids.
Statement Analysis
Statement I: Incorrect—glycolysis occurs exclusively in the cytosol across eukaryotes/plants via soluble enzymes; plants lack a complete parallel plastidial glycolytic pathway (though partial reactions like GAPCp exist, full series is cytosolic).
Statement II: Correct—the pentose phosphate pathway (PPP) has oxidative/non-oxidative branches in both cytosol (NADPH production) and plastids (chloroplast PPP for Calvin cycle precursors).
Option Breakdown
-
Both correct: Wrong; I falsely claims plastid glycolysis.
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Both incorrect: Wrong; II accurately locates PPP.
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I correct, II incorrect: Wrong; glycolysis is cytosol-only.
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I incorrect, II correct: Correct; precise compartmentalization.
Glycolysis Cytosol Plastid Overview
Glycolysis cytosol plastid debate clarifies glycolysis as a cytosolic pathway converting glucose to pyruvate (10 enzymes, net 2 ATP), absent as complete series in plastids despite some shared reactions. Essential for GATE biochemistry/plants.
Pentose Phosphate Pathway Locations
Pentose phosphate pathway spans cytosol (oxidative phase: glucose-6-P to ribulose-5-P, NADPH) and plastids (reductive/non-oxidative for nucleotide precursors/Calvin cycle). Provides metabolic flexibility.
| Statement | Location | Accuracy | Details |
| I (Glycolysis) | Cytosol only | Incorrect claim | Soluble enzymes cytosolic |
| II (PPP) | Cytosol + plastid | Correct | Dual compartments |
GATE Q.57 Solution
Statement I incorrect, II correct—glycolysis cytosol-exclusive; PPP dual-localized for NADPH/anabolism.
