Why are human sex hormones considered to be lipids?
They are hydrophilic compounds
They are made of fatty acids
They contribute to atherosclerosis
They are essential components of cell membranes
They are not soluble in water
The correct answer and explanation is :
Correct Answer:
They are not soluble in water.
Explanation:
Human sex hormones, such as testosterone, estrogen, and progesterone, are classified as lipids because they are derived from cholesterol, making them steroid hormones. One of the fundamental characteristics of lipids is their hydrophobic nature, meaning they do not dissolve in water. Instead, they are soluble in nonpolar solvents such as oils and fats.
Sex hormones belong to the steroid family, which is a subclass of lipids. These hormones have a core structure of four fused carbon rings, a hallmark of all steroids. Since they are nonpolar molecules, they cannot dissolve in the aqueous environment of the bloodstream. To circulate effectively in the body, they must bind to carrier proteins like sex hormone-binding globulin (SHBG) or albumin, which transport them to target tissues.
Unlike hydrophilic molecules, which can dissolve easily in water, lipids must pass through cell membranes in a different way. Since cell membranes are made of phospholipids, which also have hydrophobic properties, sex hormones can diffuse directly through the lipid bilayer without requiring membrane transporters. This allows them to enter cells and bind to intracellular receptors, where they regulate gene expression and influence physiological functions such as reproduction, secondary sexual characteristics, and metabolism.
Other options in the question are incorrect:
- They are hydrophilic compounds (False: Sex hormones are hydrophobic, not hydrophilic).
- They are made of fatty acids (False: Steroid hormones are derived from cholesterol, not fatty acids).
- They contribute to atherosclerosis (Not directly relevant to why they are lipids).
- They are essential components of cell membranes (False: They influence cell function but are not structural components of membranes).
This hydrophobic nature is a defining characteristic of why human sex hormones are considered lipids.