Anyone can get melasma, but it is more common among young women. Melasma often appears during pregnancy, in the second or third trimesters. Doctors don't know exactly what causes melasma, but the condition is associated with the female hormones estrogen and progesterone.
A ribosome is made of numerous proteins and RNA. Function The Golgi complex takes proteins made by the endoplasmic reticulum and exports them out of the cell as needed. It is able to keep dangerous proteins from damaging the cell which made them. It is like a packaging department ready to deliver the protein products made in the cell.
How do cells make proteins? Proteins are large, complex molecules, which all your cells are making continuously. Each protein is made up of many amino acids which must join together in the correct order for the protein to work properly. Imagine a car assembly line: to end up with a working car, the workers must know when and where to add each part. Likewise, the cell needs a set of commands for making proteins. This instruction manual is in your genes - found in the cell nucleus. Enlarge Building a protein is a bit like building a car: to end up with a working car, the workers on the assembly line must know when and where to add each part.