AQA Biology 4.1.2.3
Stem cells
Three sources, one difference that matters: how many kinds of cell each can become. Compare them, then weigh up using them.
Triple Science · Foundation tier
Start here
A cutting on the windowsill.
A short piece snipped from a houseplant is stood in a glass of water. A few weeks later it has roots, and soon it is a whole new plant.
If you had to guess, could a piece of your arm grow into a whole new you?
What can it become?
Three kinds of stem cell.
A stem cell is an undifferentiated cell. It can divide to make many more cells of the same type, and other kinds of cell can arise from it by differentiation. Pick a source and see which cells it can become.
Can become
Most types of human cell. They come from an early embryo, about 5 days old.
Used for
May be able to help conditions such as diabetes and paralysis, by making the cells that are missing or damaged.
Therapeutic cloning
An embryo with the patient’s own genes.
In therapeutic cloning, an embryo is produced with the same genes as the patient. Stem cells from the embryo are not rejected by the patient’s body, so they may be used for medical treatment. Treatment with stem cells may be able to help conditions such as diabetes and paralysis. Tap each side.
Think again · a copy of the patient?
“Therapeutic cloning makes a baby copy of the patient.”
Your call
ChooseWhat is therapeutic cloning used to produce?
Sort
Embryonic, bone marrow or meristem?
Place each statement.
Tap a card, then tap the box it belongs in. Tap a placed card to take it back.
Command words in this lesson
- Describe
- Where the stem cells come from, and what they can become.
- Compare
- Embryonic against adult: the range of cells.
- Evaluate
- Benefits, practical risks and objections, then a judgement.
Key fact
Embryonic stem cells can become most types of human cell. Adult bone marrow stem cells form a limited range, including blood cells. Meristem cells can become any type of plant cell, throughout the plant’s life.
Key note · AQA 4.1.2.3
Stem cells
- A stem cell is an undifferentiated cell that can divide to make more cells, and can differentiate into other types of cell.
- Embryonic stem cells can become most types of human cell. They may help conditions such as diabetes and paralysis.
- Adult bone marrow stem cells form a limited range of cells, including blood cells.
- Therapeutic cloning: an embryo with the patient’s genes, so its stem cells are not rejected.
- Risks include transfer of viral infection; some people have ethical or religious objections.
- Meristems, at root and shoot tips, can become any plant cell throughout the plant’s life: used to clone rare species and crops.
Photograph this card. Tomorrow, cover it and say each line first.
Previous and next
Connects to
Ask MrBadmus
Not sure how embryonic and adult stem cells differ?
Figures are schematic. The cell types shown are examples, not a complete list.