Biology Biomolecules MDCAT 2018
PMDC Verified Question 127 of 142
Glycosidic bond is formed by the:
A
Addition of oxygen
B
Removal of water
C
Addition of water
D
Removal of oxygen
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Removal of water
Concept:

Glycosidic bonds link simple sugars together via a dehydration synthesis reaction.

Solution:

  • When two monosaccharides bond to form a disaccharide, an -OH group from one sugar and an -H from the other sugar are excised.


  • These excised atoms combine to form a water molecule (\(H_2O\)), which is expelled from the reaction site.


  • Thus, the covalent O-glycosidic bond is formed precisely by the removal of water.


Why other options are incorrect:

  • Addition of water: This would describe hydrolysis (breaking the bond), not forming it.


  • Removal/Addition of oxygen: Does not account for the hydrogen atoms involved in forming the water byproduct.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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