Question

3.16 quiz: cell differentiation
which order of events is correct?
zygote → cell differentiation → mitosis
mitosis → cell differentiation → stem cells
stem cells → zygote → cell differentiation
zygote → stem cells → cell differentiation

Explanation:

• A zygote (fertilized egg) undergoes mitosis to form stem cells.
• Stem cells then differentiate into various specialized cell types.
• Let's analyze each option:
• In the option “zygote → cell differentiation → mitosis”, mitosis should occur before cell differentiation as the zygote first divides by mitosis to form more cells (including stem - like cells in early stages).
• For “mitosis → cell differentiation → stem cells”, stem cells are formed before cell differentiation in the normal developmental process. Stem cells are the undifferentiated cells that give rise to differentiated cells.
• In “stem cells → zygote → cell differentiation”, the zygote is the starting point of development, not stem cells. Stem cells are derived from the zygote through mitotic divisions.
• The option “zygote → stem cells → cell differentiation” is correct. The zygote divides by mitosis to form stem cells (in early embryonic development, there are embryonic stem cells), and then these stem cells differentiate into various cell types.

Answer:

zygote → stem cells → cell differentiation