Cell division (mitosis) and stem cells
Understand the cell cycle and mitosis, then evaluate stem cell therapies and ethics.
Teach (quick)
Cell cycle + mitosis
- Cells grow and replicate DNA.
- Then they divide by mitosis to produce two genetically identical cells.
- Mitosis is used for growth and repair.
Stem cells
Stem cells can divide and then differentiate into other cell types.
- Embryonic stem cells: can become many cell types.
- Adult stem cells: more limited.
- Plant stem cells are in meristems.
Risks + ethics
- Risks: infection, rejection, tumours.
- Ethics: embryonic stem cells involve destroying embryos.
Practice
MCQ
- What does mitosis produce?
- A Two genetically different cells
- B Two genetically identical cells
- C Four genetically different cells
- D One genetically identical cell
- Why must DNA be replicated before mitosis?
- A To make the cell bigger
- B So each new cell gets a full set of genetic material
- C To stop respiration
- D To increase diffusion
- Where are plant stem cells found?
- A In mitochondria
- B In meristems
- C In vacuoles
- D In ribosomes
Short answer
-
Describe the cell cycle at GCSE level (include DNA replication and mitosis). (3)
-
Give one benefit and one risk of using stem cells to treat disease. (2)
Exam-style (6 marks)
Stem cells can be used to treat some diseases.
Evaluate the use of embryonic stem cells compared to adult stem cells. (6)
Mark scheme (condensed)
- Mitosis: two identical cells; growth/repair
- DNA replication before division
- Meristems contain plant stem cells
- Embryonic: many cell types; ethical issues
- Adult: fewer ethical issues; limited differentiation
- Risks: rejection/infection/tumours