Final answer:
Estrone is classified as a secondary estrogen and is naturally produced in the body, particularly after menopause, distinguishing it from synthetic estrogens, which are man-made hormones used therapeutically.
Step-by-step explanation:
Estrone is a type of estrogen that is classified as a secondary estrogen, not a synthetic estrogen. Estrogens are a class of hormones that play a vital role in the growth and development of the female reproductive system, secondary sex characteristics, and maintenance of pregnancy. Among the estrogens, estrone is produced primarily in the ovaries and is one of the main forms of estrogen found in postmenopausal women. Unlike estrone, synthetic estrogens, such as ethynyl estradiol used in oral contraceptives, are artificially created and serve to prevent ovulation by mimicking the release of natural hormones during pregnancy.
Steroid hormones, including estrogen and testosterone, are derived from cholesterol and are essential in regulating various bodily functions. These hormones are transported in the bloodstream bound to proteins, such as Sex Hormone Binding Globulin (SHBG), and exert their effects by penetrating target cells and influencing gene expression within the nucleus.