Final answer:
Lipids serve as signaling molecules like steroid hormones, and as protectants and insulators in the form of subcutaneous fats. Phospholipids are also crucial for the structural integrity and fluidity of cell membranes.
Step-by-step explanation:
Besides energy storage and membrane composition, lipids perform several critical functions in biological systems. Two notable functions of lipids are:
- Signaling Molecules: Lipids such as steroid hormones (which are a class of steroids) serve vital signaling roles. For example, testosterone and estrogen are steroids that act as hormones regulating a myriad of physiological processes, including growth, immune function, and reproductive health.
- Protection and Insulation: Specific lipids, such as subcutaneous fat in animals, provide thermal insulation and mechanical protection. These fats are generally composed of triglycerides, which are types of fats stored in the body's adipose tissue.
Another lipid type worth mentioning for its vital role is the phospholipids, which are critical for cell membrane structure, providing the necessary barrier and fluidity for cellular function.