The second carbon is connected to the amino group. Amino means there is an NH 2 group bonded to the carbon atom. In the image, you see a + and a -. Those positive and negative signs are there because, in amino acids, one hydrogen atom moves to the other end of the molecule. An extra H gives you a positive charge.
Ranges of normal estrogen levels are measured in parts pg/ml of estradiol. In normal reproductive age women, during the menstrual cycle, estradiol levels range from 50-400 pg/ml. The actual normal level of estrogen varies during different parts of the menstrual cycle. In menopause, the general range may be 10-20 pg/ml.
Normal Levels. According to MedlinePlus.com, a normal testosterone level for an adult female is 20 to 80 nanograms per deciliter. Testosterone levels fluctuate during the day, but are highest in the morning so blood should be drawn as close to the morning as possible. Some laboratories may have different normal testosterone ranges.