AQA GCSE Biology Foundation (8461), Foundation tier · Cell biology › Cell division
Practise Stem cells. 5 exam-style questions plus unlimited generated ones on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
What stem cells are, where they are found in embryos, adults and plants, and how they could be used in medicine and to clone plants. Expect recall questions and a longer 'evaluate' question weighing up benefits, risks and ethical issues.
Key facts
Stem cell: an undifferentiated cell that can make more cells of the same type and can differentiate into other types
Embryonic stem cells: can form most types of human cell
Adult bone marrow stem cells: form many types of cell, including blood cells
Meristems (root and shoot tips): can form any type of plant cell, throughout the plant's life
Possible treatments: diabetes, paralysis
Risks and issues: viral infection; ethical and religious objections
Meristem cloning: fast and cheap; protects rare species; copies crops with useful features
Notes
What stem cells are
diagram
A stem cell is an undifferentiated cell. It can divide to make many more cells of the same type, and other types of cell can form from it by differentiation.
Stem cells are undifferentiated: they can divide, and they can differentiate into other types of cell.
Embryonic stem cells (from human embryos) can be cloned and made to differentiate into most types of human cell.
Adult stem cells, e.g. from bone marrow, can form many types of cell, including blood cells, but fewer types than embryonic stem cells.
Meristem tissue in plants (at the tips of roots and shoots) can differentiate into any type of plant cell, throughout the life of the plant.
Uses in medicine
Treatment with stem cells may be able to help conditions such as diabetes (replacing insulin-producing cells) and paralysis (replacing damaged nerve cells).
Adult stem cells from bone marrow are already used, e.g. in bone marrow transplants to treat some blood cancers.
Risks and issues
Stem cells grown in a laboratory could be infected with a virus, which would then be passed to the patient.
Some people have ethical or religious objections: embryos are destroyed to collect the stem cells, and some believe an embryo has a right to life.
Treatments are still being researched and may not work. Cells that keep dividing could also form a tumour.
Adult stem cells raise fewer objections (no embryo is destroyed) but can form fewer types of cell.
Plant meristems
Meristem cells can be used to produce clones of plants quickly and economically.
Rare species can be cloned to protect them from extinction.
Crop plants with special features, such as disease resistance, can be cloned to produce large numbers of identical plants for farmers.
How to answer each type of question
Compare stem cells from different sources
1 to 2 marksGrade 4
State which cells each type of stem cell can form.
Write it as a comparison, using 'but' or 'whereas'.
Example. Give one difference between stem cells from a human embryo and stem cells from adult bone marrow.
Show the model answerHide the model answer
Embryonic stem cells can differentiate into most types of human cell, whereas adult bone marrow stem cells can form fewer types, such as blood cells (1).
Give reasons for cloning plants from meristems
2 to 3 marksGrade 5
Speed and cost: clones are produced quickly and economically.
Conservation: rare species can be saved from extinction.
Crops: every clone has the same useful feature, e.g. disease resistance.
Example. Give two reasons why plant growers use meristem tissue to clone plants.
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Any two from: large numbers of plants can be produced quickly (1) it is cheap / economical (1) all the plants have the same desired features, e.g. disease resistance (1) rare species can be protected from extinction (1)
Don’t lose marks
Saying adult stem cells can become any type of cell. Bone marrow stem cells form only some types, such as blood cells.
Saying stem cells are 'specialised'. They are undifferentiated.
Saying therapeutic cloning produces a baby. It produces an embryo as a source of stem cells.
Writing a one-sided answer to an 'evaluate' question, with no risks or no conclusion.
Giving vague ethical points, such as 'it is wrong'. Say why: embryos are destroyed, and some believe an embryo has a right to life.
More tips
Memory tricks
Three sources of stem cells: Embryos, Adult bone marrow, Meristems ('EAM').
Stem cell uses in medicine: think 'D and P': Diabetes and Paralysis.
Evaluate = both sides + a conclusion. No conclusion, no top level.
Exam technique
In 6-mark 'evaluate' questions, plan quickly: benefits, risks, ethics, conclusion.
Use the words 'undifferentiated' and 'differentiate' when you describe stem cells.
If the question is about plants, write about meristems and cloning, not embryos.
What each grade needs
What you need to be able to do, from the first marks up to the top grade.
Grade 3
State what a stem cell isAn undifferentiated cell that can make more cells of the same type and can differentiate into other types of cell.
Grade 4
Name where stem cells are foundIn embryos, in adult bone marrow, and in the meristems of plants.
Grade 5
Compare embryonic and adult stem cellsEmbryonic stem cells can become most types of human cell; adult bone marrow stem cells form fewer types, including blood cells.
Grade 5
Describe uses of meristem cloningMaking clones quickly and cheaply, saving rare species, and producing crops with useful features.
Quick recall
Cover the answers and test yourself. The app has these as flashcards that come back just before you'd forget them.
Stem cells are found in animals and plants. Name the tissue in plants that contains stem cells.
meristem
Therapeutic cloning can be used to produce stem cells for a patient. The steps are listed below, but they are not in the correct order.
A Stem cells are removed from the embryo.
B The nucleus is removed from an egg cell from a donor.
C The egg cell divides to form an embryo.
D The nucleus from one of the patient’s body cells is put into the egg cell.
E The stem cells are made to differentiate into the type of cell the patient needs.
Write the letters A to E in the correct order.
B, D, C, A, E
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy4 marks
Stem cells are found in animals and plants.
(a) Which statement describes a stem cell? Tick (✓) one box.[1]
A cell that has no nucleus
A specialised cell that can no longer divide
An undifferentiated cell that can give rise to many more cells of the same type
A cell that is found only in plant stems
(b) Name the tissue in plants that contains stem cells.[1]
(c) Name one type of cell that stem cells from adult bone marrow can form.[1]
(d) Give one medical condition that treatment with stem cells may be able to help.[1]
Show the answer and mark scheme
(a)Answer: An undifferentiated cell that can give rise to many more cells of the same type
(b)Answer: meristem
meristem (tissue)
(c)
blood cells / red blood cells / white blood cells / platelets
(d)
diabetes / paralysis
Question 2Medium5 marks
Stem cells can be taken from human embryos or from adult bone marrow.
(a) Give one difference between stem cells from embryos and stem cells from adult bone marrow.[1]
(b) Describe how therapeutic cloning is used to produce stem cells for a patient. Explain why these stem cells are useful for medical treatment.[3]
(c) Give one risk of using stem cells in medical treatment.[1]
Show the answer and mark scheme
(a)
embryonic stem cells can differentiate into most types of human cell, but adult bone marrow stem cells can form only some types, e.g. blood cells
(b)
an embryo is produced with the same genes as the patient
stem cells are taken from the embryo (and made to differentiate into the cells needed)
the cells are not rejected by the patient’s body / immune system