Chemically an antibody is

Options

A. Protein
B. Lipid
C. Lipoprotein
D. Nucleoprotein

Answer

To answer the question "Chemically an antibody is," we will follow these steps:

### Step 1: Understand the Structure of Antibodies
Antibodies, also known as immunoglobulins, are Y-shaped molecules that play a crucial role in the immune response. They are composed of chains of amino acids.

**Hint:** Think about the basic building blocks of antibodies and their structural components.

### Step 2: Identify the Components of Antibodies
Antibodies consist of two heavy chains and two light chains, which are linked by disulfide bonds. This structure is often represented as H2L2, indicating two heavy (H) and two light (L) chains.

**Hint:** Recall the terminology used to describe the chains in antibodies.

### Step 3: Classify Antibodies
There are five main classes of antibodies: IgA, IgD, IgM, IgG, and IgE. Each class has a specific function and structure but they all share the same basic protein structure.

**Hint:** Consider the different types of antibodies and their roles in the immune system.

### Step 4: Determine the Chemical Composition
Chemically, antibodies are classified as proteins because they are made up of long chains of amino acids. This proteinaceous nature is what allows them to perform their functions in the immune response.

**Hint:** Focus on the chemical classification of antibodies and how they relate to proteins.

### Step 5: Conclusion
Based on the understanding that antibodies are composed of amino acids and have a protein structure, we conclude that chemically, an antibody is a protein.

**Final Answer:** The correct answer is **protein**.