b2 cell division
4 detailed 50-minute lessons with teaching scripts, worked examples, parent guides, and assessment criteria.
Lesson Overview
Total Lessons: 4
Tier: Foundation and Higher
Duration: 50 minutes per lesson (200 minutes total)
Exam Boards: AQA, Edexcel, OCR, Eduqas, CCEA
Tier: Foundation and Higher
Duration: 50 minutes per lesson (200 minutes total)
Exam Boards: AQA, Edexcel, OCR, Eduqas, CCEA
Learning Objectives
- Explain the key ideas of b2 cell division
- Apply b2 cell division to exam-style questions
- Develop independent study skills
- Build cross-topic connections
Prerequisites
- Read the revision notes for b2 cell division first (GCSE Revise summary)
- Key vocab to pre-teach: Cell division, Chromosomes
- Basic skills: reading the summary notes and answering the practice questions there
Materials & Equipment
- Exercise book, coloured pens
- Scientific calculator
- Ruler
- Printed revision notes (link below)
- Internet for videos (see Resources)
Lesson 1: Introduction: b2 cell division
Duration: 50 minutes
Starter Activity (5 minutes)
Quick Recall
Write down everything you already know about b2 cell division. Then check against the key terms: Cell division, Chromosomes. Use a mini-whiteboard or paper.
Main Content (35 minutes)
Parent/Teacher Guide:
Before lesson: Read the script below. Pre-teach key vocab: Cell division, Chromosomes.
If stuck: Re-read the revision notes (link above), then break the content into smaller steps.
Extension: See the Stretch & Challenge ideas in Lesson 4.
Before lesson: Read the script below. Pre-teach key vocab: Cell division, Chromosomes.
If stuck: Re-read the revision notes (link above), then break the content into smaller steps.
Extension: See the Stretch & Challenge ideas in Lesson 4.
Teaching Script (35 mins):
Mins 0-5 - Hook: "Today: b2 cell division. By the end you will be able to answer exam questions on it unaided. It connects to the rest of Combined Science (Trilogy) because the ideas here recur across the spec."
Mins 5-20 - Direct Instruction: Work through the core ideas below one at a time; after each, ask your student to explain it back in their own words.
Mins 20-30 - Guided Practice: Model the worked example together, then let your student attempt the first practice question with guidance.
Mins 30-35 - Independent Practice: 2-3 practice questions from Lesson 3 below, with immediate feedback.
Mins 0-5 - Hook: "Today: b2 cell division. By the end you will be able to answer exam questions on it unaided. It connects to the rest of Combined Science (Trilogy) because the ideas here recur across the spec."
Mins 5-20 - Direct Instruction: Work through the core ideas below one at a time; after each, ask your student to explain it back in their own words.
Mins 20-30 - Guided Practice: Model the worked example together, then let your student attempt the first practice question with guidance.
Mins 30-35 - Independent Practice: 2-3 practice questions from Lesson 3 below, with immediate feedback.
First Look
Start with the revision notes summary, then attempt: Describe the stages of the cell cycle. (3 marks)
Plenary (5 minutes)
Check Out
Your student states one thing they learned and one question they still have about b2 cell division.
Lesson 2: Core Concepts: b2 cell division
Duration: 50 minutes
Starter Activity (5 minutes)
Review Previous Lesson
Quick recap: write 3 key points from Lesson 1 on b2 cell division. Check them against the notes below.
Main Content (35 minutes)
Cell division: is how organisms grow and repair damaged tissues. New cells are produced when existing cells divide. In humans, this happens constantly - for example, your skin cells divide every few hours to replace worn-out cells.
Chromosomes: are structures in the nucleus that contain DNA (genetic material). Human body cells have 46 chromosomes (23 pairs). Sex cells (gametes) have 23 chromosomes (one of each pair).
| Term | Meaning | Example |
|---|---|---|
| Embryonic stem cells | Early-stage embryo (4-5 days old) | Any type of cell in the body (totipotent/pluripotent) |
| Adult stem cells | Body tissues (e.g. bone marrow) | Limited range of cell types related to their tissue |
| Could cure many serious diseases | Embryo is destroyed - some see this as taking a potential life | |
| Improves quality of life for many people | Each embryo has the potential to become a human being | |
| Embryos used are often from IVF and would be destroyed anyway | Adult stem cells could be used instead (fewer ethical issues) | |
| Research is heavily regulated | Could lead to slippery slope of embryo exploitation |
Practice (10 minutes)
Q: Describe the stages of the cell cycle. (3 marks)
Answer: The cell grows and increases the number of organelles; the DNA is replicated (copied); mitosis occurs where the nucleus divides to produce two identical nuclei, then the cytoplasm and cell membrane divide.
Plenary (5 minutes)
Explain Back
Your student teaches the key points back to you without looking. Fill any gaps immediately.
Lesson 3: Application: b2 cell division
Duration: 50 minutes
Starter Activity (5 minutes)
Quick Recall
Recall the key terms: Cell division, Chromosomes. Define each in one sentence.
Main Content (35 minutes)
Parent/Teacher Guide: Let your student attempt each question alone first, then compare with the model answer. Award method marks for correct working even if the final answer is wrong.
Q1: Describe the stages of the cell cycle. (3 marks)
Answer: The cell grows and increases the number of organelles; the DNA is replicated (copied); mitosis occurs where the nucleus divides to produce two identical nuclei, then the cytoplasm and cell membrane divide.
Q2: How many chromosomes are in a human body cell?
Answer: 46 chromosomes (23 pairs)
Q3: Explain why mitosis is important for growth and repair. (3 marks)
Answer: Mitosis produces new cells that are genetically identical to the parent cell. For growth, this means organisms can produce more cells to increase in size. For repair, mitosis replaces damaged or worn-out cells with identical copies that function the same way.
Q4: What is a stem cell?
Answer: A stem cell is an undifferentiated cell that has not yet specialised. It can divide to produce more stem cells, or differentiate into a specialised cell type.
Q5: Explain the difference between embryonic stem cells and adult stem cells. (2 marks)
Answer: Embryonic stem cells can differentiate into any type of cell in the body, whereas adult stem cells can only differentiate into a limited range of cell types related to their tissue of origin.
Q6: Discuss the ethical issues relating to the use of embryonic stem cells in medical research. (4 marks)
Answer: See Example 5 above - include arguments both for and against, showing both sides of the debate.
Plenary (5 minutes)
Error Review
Review any questions answered incorrectly. Identify whether the error was knowledge, method, or reading the question.
Lesson 4: Exam Practice: b2 cell division
Duration: 50 minutes
Starter Activity (5 minutes)
Command Words
Review what these command words require: state (one point), describe (say what happens), explain (say why), compare (both sides), evaluate (judgement).
Main Content (35 minutes)
Extended Answer
Extended question: Extended Answer 6 marks: Discuss the ethical issues of using embryonic stem cells compared with adult stem cells in medical research. <div class="
Embryonic stem cells can differentiate into any cell type, making them potentially more useful for treating a wide range of diseases such as paralysis and diabetes. However, to harvest embryonic stem cells the embryo is destroyed, which some people believe is unethical as the embryo has the potential to become a human life. Adult stem cells, such as those from bone marrow, avoid this ethical issue because the donor is not harmed. However, adult stem cells can only differentiate into a limited range of cell types, reducing their medical usefulness. Some people argue that embryos from IVF would be destroyed anyway, so using them for research is justified. Others worry about a slippery slope towards embryo exploitation. Therapeutic cloning could produce genetically matched embryonic stem cells but still requires embryo destruction. Mark scheme: 1 mark for embryonic advantage; 1 mark for ethical objection to embryo use; 1 mark for adult stem cell advantage; 1 mark for adult stem cell limitation; 1 mark for IVF counter-argument; 1 mark for balanced discussion
Exam Tips: When describing the cell cycle, mention growth, DNA replication AND mitosis - all three stages | "Two genetically identical daughter cells" - always say "identical" when describing mitosis | Don't confuse mitosis with meiosis - mitosis produces identical cells; meiosis produces gametes | For stem cell ethics questions, always give both sides of the argument | Remember: bone marrow transplant = adult stem cells (not embryonic) | Exam questions often ask you to "discuss" ethical issues - this means give arguments for AND against
Common Errors: Watch Out! 1. Wrong: Mitosis produces identical cells so there is no variation Correct: Mitosis produces genetically identical cells, but mutations can occur during DNA replication, introducing variation 2. Wrong: Stem cells can become any cell type forever Correct: Stem cells differentiate and lose potency — adult stem cells are already partially specialised and can only form limited cell types
AO3 - Reasoning & Interpretation: Analysis and Evaluation A study tested stem cell therapy on 50 patients with spinal cord injuries. 30 patients received stem cell treatment and 20 received a placebo. After 6 months, 18 of the treated group and 4 of the placebo group showed improvement. (a) Calculate the percentage improvement in each group. (b) Evaluate whether the stem cell therapy was effective. Answers: (a) Treated: (18/30) × 100 = 60%. Placebo: (4/20) × 100 = 20%. (b) The therapy appears effective — 60% improved vs 20% in placebo. However, the groups are unequal in size (30 vs 20), and the study is small. A larger trial with equal group sizes and longer follow-up would strengthen the conclusion.
Stretch & Challenge (Grade 8-9):
- Synoptic links: explain how b2 cell division connects to another Combined Science (Trilogy) topic you have studied
- Real-world: research one real-world use or example of b2 cell division
- Critical: "What are the limitations of the models used in b2 cell division?"
Plenary (5 minutes)
Assessment Criteria
- Got it: Confident explanation + correct worked examples
- Getting there: Main points OK, needs support with detail
- Not yet: Confused on key concepts - re-run Lesson 2
Homework & Consolidation
- Consolidation: Re-answer any Lesson 3 practice questions answered incorrectly (20 mins)
- Retrieval: Write flashcards for the key terms: Cell division, Chromosomes (10 mins)
- Exam practice: One past-paper question on b2 cell division from the board websites (15 mins)
- Extension: Explain b2 cell division to someone else in your own words (10 mins)