An IgG molecule has two
A) heavy chains, light chains, AND antibody binding sites.
B) heavy chains, light chains, AND antigen binding sites.
C) light chains, antigen binding sites, AND antibody binding sites.
D) antibody binding sites AND antigen binding sites.
E) Fc regions AND one Fab region.

Question

An IgG molecule has two
A) heavy chains, light chains, AND antibody binding sites.
B) heavy chains, light chains, AND antigen binding sites.
C) light chains, antigen binding sites, AND antibody binding sites.
D) antibody binding sites AND antigen binding sites.
E) Fc regions AND one Fab region.

Quizplus · Accepted Answer

IgG molecules are composed of two heavy chains and two light chains. Each heavy chain has one variable region (VH) and three constant regions (CH1, CH2, and CH3), and each light chain has one variable region (VL) and one constant region (CL). The variable regions of the light and heavy chains together form the antigen binding site(s), which are responsible for binding to specific antigens. Therefore, option B (heavy chains, light chains, and antigen binding sites) is the correct choice. Option A is incorrect because it includes "antibody binding sites" which is incorrect – the correct term is antigen binding site. Option C is incorrect because it includes "antibody binding sites" and lacks heavy chains. Option D is incorrect because it only includes binding sites and doesn't account for the presence of light and heavy chains. Option E is incorrect because it only mentions the regions of the IgG molecule and doesn't cover the presence of antigen binding sites.

An IgG Molecule Has Two