An IgG2 molecule is composed of?
**Core Concept**
The **immunoglobulin** structure is crucial for its function, with different classes having distinct characteristics. **IgG** is the most abundant class of antibodies in the blood, and it is divided into four subclasses: IgG1, IgG2, IgG3, and IgG4. Each subclass has a slightly different structure and function.
**Why the Correct Answer is Right**
An **IgG2** molecule is composed of two **heavy chains** (γ2) and two **light chains** (κ or λ). The heavy chains determine the class of the antibody, while the light chains contribute to the antigen-binding site. The **γ2 heavy chain** is specific to the IgG2 subclass, which has a lower affinity for most **Fc receptors** but is more effective against polysaccharide antigens.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it does not specify the correct heavy chain for IgG2.
**Option C:** Incorrect as it refers to a different subclass of IgG.
**Option D:** Incorrect because it is not a valid composition for any IgG subclass.
**Clinical Pearl / High-Yield Fact**
Remembering the structure and function of different **immunoglobulin subclasses** is crucial for understanding immune responses and immunodeficiency disorders.
**Correct Answer:** D. 2 γ2 heavy chains and 2 light chains (κ or λ).