The egg picks up the yolk proteins and yolk is stored in the vegetal pole of the egg. The animal pole contains pigment granules and is dark. Without estrogen, mRNA for yolk proteins lasts only 16 hrs in the cytoplasm. However, after estrogen, the half-life increases to 3 weeks. Once the oocyte has grown to proper size, the ovary releases progesterone.
Progesterone causes maturation of the oocyte to produce the egg.
The oocyte cannot be fertilized, the egg can. There are other changes that take place so that the cell can be successfully fertilized by sperm. In this case, M phase is meiosis and cytokinesis. It is an egg. After we visit the computer lab to demonstrate how to use our web site, you will take the review online quiz.