1.1.4: Cell differentiation
Not started yet — this one needs some love.
As a cell differentiates it gains the sub-cellular structures it needs for a particular job — it becomes a specialised cell.
In early animal development, one fertilised egg divides and differentiates into many different cell types.
In animals:
most cells differentiate early in development
in mature animals, cell division is mainly for repair and replacement (differentiation is limited)
In plants:
many cells keep the ability to differentiate throughout life → greater flexibility
Common exam mistakes
Differentiation is about cells becoming specialised — do not confuse it with cell division (mitosis).
Most adult animal cells cannot re-differentiate (unlike plant cells) — do not say all animal cells can become any cell type.
The process is: undifferentiated stem cell → differentiation → specialised cell (not the other way around).