IAL Biology Edexcel – Alternative Splicing

Complete Edexcel IAL Biology lesson (spec 3.19): exons, introns and alternative splicing, one gene giving several proteins. Ready to teach, no prep.

Lesson 27 of 32 · Topic 3 · Unit 2 (WBI12) · Spec 3.19 · 70 minutes
The question this lesson answers: how can one gene code for more than one protein?

By the end, students can

• Describe exons and introns, and the difference between pre-mRNA and active mRNA.
• Explain alternative splicing and how it gives more than one protein from one gene.
• Read a splicing diagram, and apply it to examples, including the use of active mRNA in medicine.

How the 25-slide lesson runs
A retrieval starter, a recap and “the puzzle”, then inside a gene (exons and introns), pre-mRNA v active mRNA, and splicing from pre-mRNA to active mRNA. One pre-mRNA gives two active mRNAs, which give different proteins, followed by reading a splicing diagram in five steps and three examples of one gene making several proteins. Active mRNA in medicine, “words that lose marks” and a “what 3.19 questions ask” slide lead into a quick check and two real WBI12 questions with official mark schemes and model answers: October 2020 Q7, part c, and June 2024 Q5, part b. An exit ticket closes the lesson.

Marks students usually lose here

• Saying splicing happens in the cytoplasm, when it happens in the nucleus before the mRNA leaves.
• Writing that introns “are not DNA” or “are junk”, when they are transcribed and then removed from the pre-mRNA.
• Describing alternative splicing as “different genes”, rather than different exons joined in different combinations.

In the folder (13 files)

• PowerPoint, 3-page lesson plan and 14-page student notes with a one-page knowledge organiser
• 8 practice questions (26 marks) and mark scheme, each question on its own page
• 17-mark homework (a 3 600-nucleotide pre-mRNA with four exons, why introns must go, plus spaced retrieval) with mark scheme
• 5-question misconception check with teacher key
• 14 pages of active-learning printables: Cut and join, Order the steps, and Diagram detectives
• 11 pages of teacher notes (starter and exit mark points, a step-by-step run sheet for every active-learning activity, answer keys), plus catch-up and extension bank decks

Follows Lesson 26 (differential gene expression); Lesson 28 moves to genotype, environment and epigenetics. 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.