Biology Biomolecules MDCAT 2019
PMDC Verified Question 118 of 142
In glycine, 'R' is ____.
A
Hydrogen
B
Methane
C
Ethane
D
Fatty acid
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Hydrogen
Concept:

The R-group (side chain) is the only variable part distinguishing one amino acid from another.

Solution:

  • Glycine is the absolute simplest and smallest of all 20 standard amino acids.


  • Its unique 'R' variable group is simply a single Hydrogen atom (-H).


  • Because its side chain is so small, glycine can fit into very tight spatial environments where other amino acids cannot.


Why other options are incorrect:

  • Methane/Ethane: These are independent hydrocarbon gases. (A methyl group -CH3 is found in Alanine).


  • Fatty acid: A massive lipid monomer, entirely unrelated.

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.

Previous Question All Biomolecules MCQs Next Question

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.

Enter Arena Sprint iOS App Android App