**Core Concept:**
Neisseria gonococcus (GC) and Neisseria meningitidis (MC) are closely related bacteria that share some similarities. However, understanding the differences between these two organisms can aid in their identification and appropriate management.

**Why the Correct Answer is Right:**
Gonococcus and meningococcus are both diplococci, meaning they are bacteria with two cell walls. However, the distinguishing feature lies in their capsules. Neisseria gonococcus produces a thin polysaccharide capsule, while Neisseria meningitidis forms a thick polysaccharide capsule. This difference allows for the classification of MC into serogroups based on the antigenic properties of their capsule, while GC does not follow such serogrouping.

**Why Each Wrong Option is Incorrect:**
A. Thick capsule: This is a feature of Neisseria meningitidis, not gonococcus.
B. No capsule: This is incorrect as both gonococcus and meningococcus have capsules; the difference lies in their thickness.
C. Thin capsule: This is a feature of gonococcus, not meningococcus.
D. Serogrouping: Neisseria gonococcus does not undergo serogrouping due to its thin capsule.

**Clinical Pearl:**
Understanding the capsule thickness of these bacteria can help in differentiating between Neisseria gonococcus and Neisseria meningitidis, which is crucial in clinical practice, particularly when identifying the causative organism in a patient's sample (e.g., urine, blood, or cerebrospinal fluid) and choosing the appropriate antibiotic treatment.

**Correct Answer:** D. No capsule