AQA GCSE Biology (8461) — Cell Biology
Almost all cells in a multicellular organism contain identical genetic information, yet they look and act entirely differently. This happens through a step-by-step mechanism:
There is a major difference in when plant and animal cells lose their ability to differentiate.
| Feature | Animal Cells | Plant Cells |
|---|---|---|
| Timing of differentiation | Most differentiate at an early developmental (embryonic) stage. | Many retain the ability to differentiate throughout their entire life. |
| Location of unspecialised cells |
| A small number of restricted adult stem cells remain in specific locations (e.g., bone marrow). |
| Unspecialised cells are found in the meristem tissue at the growing tips of roots and shoots. |
| Regeneration capability | Most cells lose the ability to differentiate further once specialised. | Can continuously grow and even regrow entirely from stem cuttings. |
To function effectively, specialised cells acquire specific adaptations. You must be able to link these acquired structures directly to their function.
Animal Cells:
Plant Cells:
Students often write that mitochondria 'make' or 'create' energy; you must always state that they 'release energy via respiration' to avoid losing a mark.
When explaining the mechanism of how a cell becomes specialised, examiners look for the exact AQA phrasing: state that the cell 'acquires different sub-cellular structures'.
In 4-mark comparison questions about differentiation timing, ensure you explicitly state both sides: animal cells differentiate at an early stage, whereas plant cells retain the ability throughout life.
If an exam question asks about the purpose of cell division in mature animals, you must write the exact phrase 'repair and replacement' to secure the mark.
Zygote
A single unspecialised cell that a multicellular organism generally begins as.
Mitosis
A type of cell division that results in two genetically identical daughter cells, used for growth, repair, and replacement.
Cell differentiation
The process by which a cell changes to become specialised for its function by acquiring specific sub-cellular structures.
Genes
A short section of DNA that codes for a specific protein.
Gene expression
The process of turning specific genes on or off, dictating which proteins a cell produces.
Sub-cellular structures
The distinct parts inside a cell (e.g., nucleus, mitochondria, ribosomes) that perform specific tasks.
Specialised cell
A cell that has developed a specific structure and set of organelles to perform a particular job within an organism.
Adult stem cells
Undifferentiated cells found in mature organisms that can only differentiate into a restricted range of related cell types.
Meristem
Region of unspecialised cells in a plant (at the tips of roots and shoots) capable of continuous cell division and differentiation.
Repair and replacement
The primary purpose of cell division (mitosis) in mature animals, used to heal damaged tissues or replace dead cells rather than for net growth.
Neurone
A specialised animal cell (nerve cell) adapted to rapidly carry electrical impulses throughout the body.
Lignin
A chemical that strengthens the cell walls of xylem vessels, causing the cells to die and form hollow transport tubes.
Put your knowledge into practice — try past paper questions for Biology
Zygote
A single unspecialised cell that a multicellular organism generally begins as.
Mitosis
A type of cell division that results in two genetically identical daughter cells, used for growth, repair, and replacement.
Cell differentiation
The process by which a cell changes to become specialised for its function by acquiring specific sub-cellular structures.
Genes
A short section of DNA that codes for a specific protein.
Gene expression
The process of turning specific genes on or off, dictating which proteins a cell produces.
Sub-cellular structures
The distinct parts inside a cell (e.g., nucleus, mitochondria, ribosomes) that perform specific tasks.
Specialised cell
A cell that has developed a specific structure and set of organelles to perform a particular job within an organism.
Adult stem cells
Undifferentiated cells found in mature organisms that can only differentiate into a restricted range of related cell types.
Meristem
Region of unspecialised cells in a plant (at the tips of roots and shoots) capable of continuous cell division and differentiation.
Repair and replacement
The primary purpose of cell division (mitosis) in mature animals, used to heal damaged tissues or replace dead cells rather than for net growth.
Neurone
A specialised animal cell (nerve cell) adapted to rapidly carry electrical impulses throughout the body.
Lignin
A chemical that strengthens the cell walls of xylem vessels, causing the cells to die and form hollow transport tubes.
