Question

Cement layer of cuticle is composed of:

• A. Tyrosins
• B. Lipoproteins
• C. Hexamerins
• D. Carbohydrate

Hint:

Epicuticle layers from outside to inside:
1. Cement layer (composed of Lipoproteins).
2. Wax layer (composed of Long-chain Hydrocarbons).
3. Polyphenol layer.
4. Cuticulin layer.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The insect integument (cuticle) consists of an outer thin epicuticle and an inner thick procuticle.
The epicuticle itself is subdivided into multiple layers that prevent water loss and protect against mechanical damage.

Step 2: Detailed Explanation:
The outermost layer of the epicuticle is the cement layer.
It is secreted shortly after molting by dermal glands located in the epidermis.
The cement layer consists of a hard, protective mixture of lipids and proteins (lipoproteins), which acts like a varnish protecting the underlying wax layer from abrasion and dust.

Step 3: Final Answer:
The cement layer is composed of lipoproteins, which corresponds to option (B).