Question

Draw only the structure of antibody molecule.

Hint:

Antibody = Y-shaped with 2 heavy + 2 light chains. Fab = antigen binding, Fc = constant region.

Answer 1

The antibody (immunoglobulin) is a Y-shaped glycoprotein molecule made up of: \[\begin{array}{rl} \bullet & \text{Two identical heavy (H) chains.} \\ \bullet & \text{Two identical light (L) chains.} \\ \bullet & \text{Variable region at the tips of the arms for antigen binding.} \\ \bullet & \text{Constant region forming the stem of the Y.} \\ \end{array}\] Diagram:
\begin{center} \begin{tikzpicture}[scale=1.0, line width=1pt] % Left light chain \draw (0,0) -- (1,2); % Left heavy chain \draw (0,-2) -- (1,2); % Right light chain \draw (4,0) -- (3,2); % Right heavy chain \draw (4,-2) -- (3,2); % Base/stem \draw (1,-2) -- (2,-4) -- (3,-2); % Labels \node at (0.5,1.5) {Light chain}; \node at (3.5,1.5) {Light chain}; \node at (-0.3,-1) {Heavy chain}; \node at (4.3,-1) {Heavy chain}; \node at (2,-3.8) {Fc (constant region)}; \node at (2,2.3) {Fab (antigen-binding site)}; \end{tikzpicture} \end{center}