IAL Biology Edexcel – Differential Gene Expression

Complete Edexcel IAL Biology lesson (spec 3.18): differential gene expression as a five-step chain, worked examples and gene-activity graphs.

Lesson 26 of 32 · Topic 3 · Unit 2 (WBI12) · Spec 3.18 · 63 minutes
The question this lesson answers: how do cells with the same DNA become different from each other?

By the end, students can

• Explain differential gene expression as a chain: gene switched on, mRNA transcribed, protein made, cell specialised.
• Apply the chain to worked examples in animal and plant cells, and avoid the wording that loses marks.
• Read gene-activity data and say what it shows.

How the 23-slide lesson runs
A retrieval starter, then worked examples in animal cells, plant cells specialising in the same way, and “more genes are switched off as development goes on”. “Words that lose marks” and reading gene-activity graphs come next, with a “what 3.18 questions ask” slide and a quick check. Three real WBI12 questions have official mark schemes and model answers: October 2019 Q8, part c(ii); October 2020 Q7, part d; and January 2020 Q7, part c. “Build your own answer, then check it” and an exit ticket close the lesson.

Marks students usually lose here

• Saying cells “lose” the genes they do not use, when every cell keeps the whole genome.
• Skipping a link in the chain, for example gene to specialised cell with no mRNA or protein.
• Describing a graph without data from it, or without saying which gene’s activity rose and which fell.

In the folder (13 files)

• PowerPoint, 3-page lesson plan and 12-page student notes with a one-page knowledge organiser
• 8 practice questions (29 marks) and mark scheme, each question on its own page
• 17-mark homework (ordering the events from active gene to specialised cell, why skin cells have keratin, a two-gene activity table) with mark scheme
• 5-question misconception check with teacher key
• 5 pages of active-learning printables: Graph detectives
• 7 pages of teacher notes (starter and exit mark points, a step-by-step run sheet for the active-learning activity, answer keys), plus catch-up and extension bank decks

Follows Lesson 25 (stem-cell therapy, ethics, and the start of gene expression); Lesson 27 shows how one gene can code for several proteins. The full 32-lesson Topic 3 bundle is in my shop.

An independent resource by bio_boffin_resources, written by a Biology teacher with 10 years’ experience in a leading international school. Not endorsed by Pearson.