BRAINCAKEDevelopment of an Organism
Every cell in a multicellular organism comes from a single fertilised egg, the zygote. The zygote is totipotent: it can give rise to every cell type in the body and also the placenta and membranes around the embryo.
The zygote divides repeatedly by mitosis. In mammals this produces a solid ball of cells and then, after about five days, a hollow ball called the blastocyst. The outer layer of the blastocyst forms the placenta, while the inner cell mass forms the embryo itself. Cells of the inner cell mass are pluripotent: they can become any cell of the body, but not the placenta.
Sign in free to see the rest of this lesson, the R.E.C.I.P.E. recall steps and the quiz
BrainCake is free. Make an account in seconds and pick up where this page stops.
More in Gene Expression
- Umbilical Cord Stem Cells
- Adult Stem Cells
- Determination of Cell Type
- Evidence for Cell Determination
- Epigenetic Control of Development
- Epigenetic Control of Gene Expression
- Stem Cell Therapy
- Therapeutic Cloning
All 39 lessons in Gene Expression · All Edexcel A-level Biology topics