How Do Cells Become Specialised?
Part of Stem Cells and Cell Differentiation — GCSE Biology
This how it works covers How Do Cells Become Specialised? within Stem Cells and Cell Differentiation for GCSE Biology. Stem cell types, differentiation processes, therapeutic applications, embryonic vs adult stem cells, and ethical considerations It is section 6 of 16 in this topic. Use this how it works to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 6 of 16
Practice
20 questions
Recall
25 flashcards
🔬 How Do Cells Become Specialised?
All the cells in your body, from muscle cells to nerve cells to red blood cells, contain exactly the same DNA. They all started as identical cells in the early embryo. So how do they end up looking and behaving so differently?
The answer is differentiation — the process by which cells switch certain genes on and off.
- Same DNA, different expression: Every cell in your body has the same full set of approximately 20,000 genes. However, not all genes are active in every cell. In a muscle cell, the genes for producing contractile proteins are switched on; the genes for producing digestive enzymes are switched off. In a pancreatic cell, the reverse is true.
- Genes control protein production: When a gene is "switched on," the cell reads it and produces a specific protein. These proteins determine the cell's structure (e.g., the shape of a red blood cell), chemical reactions it carries out, and what substances it secretes.
- Structure follows function: As specific proteins are produced, the cell physically changes — it develops the shape, internal structures, and surface molecules that allow it to perform its specialised role. For example, red blood cells lose their nucleus to make more room to carry haemoglobin.
- Generally irreversible in animals: Once an animal cell has differentiated, it normally cannot change back into a different cell type. The gene expression pattern becomes fixed. This is why, if a nerve cell is destroyed, the body cannot simply make another one from a skin cell.
- Plants retain more flexibility: Many plant cells remain capable of dedifferentiating — reverting to an unspecialised state and then differentiating again. This is why you can grow a whole new plant from a single leaf cutting; individual plant cells retain totipotency throughout their lives.
Key exam point: Differentiation does NOT change the DNA sequence. Every cell still has all the genes. What changes is which genes are being expressed (read and used to make proteins).