Biology Biomolecules PMC 2020
PMDC Verified Question 106 of 142
Monosaccharides have a general formula represented by:
A
\( C(H_2O)_n \)
B
\( C_n(H_2O)_n \)
C
\( (CH_2O)_n \)
D
\( C_5(H_2O)_n \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: \( C_n(H_2O)_n \)
Concept:

The term "carbo-hydrate" historically stems from the observation that these molecules appear to be "hydrates of carbon".

Solution:

  • The general stoichiometric formula for simple monosaccharides is typically represented as \( C_n(H_2O)_n \).


  • This reflects that for every carbon atom, there is roughly the equivalent of one water molecule (two hydrogens and one oxygen), yielding a 1:2:1 ratio of C:H:O.


  • Here, \( n \) is a whole number ranging from 3 to 7.


Why other options are incorrect:

  • \( C_5(H_2O)_n \): Incorrectly limits the carbon count strictly to 5.


  • \( C(H_2O)_n \): Suggests only one carbon atom exists in the molecule, which is chemically impossible for sugars.

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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