A Level Biology: Lesson 175

Gene Mutations: Deletions and Substitutions

Task 1. Check Where this Lesson fits into your Exam Specification!

Task 2. Watch the Revision Notes Lesson in Full.

00:00 Intro | Learning Outcomes

00:43 Mistakes Happen...

01:21 Deletions and Substitutions.

01:37 Fame shift Mutation

04:06 The Degenerate Code.

05:04 Gene Mutation: Substitution.


Check Your Spec!

★ AQA Specification Reference: - 3.4.3 Genetic diversity can arise as a result of mutation. Gene mutations involve a change in the base sequence of chromosomes. They can arise spontaneously during DNA replication and include base deletion and base substitution. Due to the degenerate nature of the genetic code, not all base substitutions cause a change in the sequence of encoded amino acids. 3.8.1 Alteration of the sequence of bases in DNA can alter the structure of proteins (A-level only). Gene mutations might arise during DNA replication. They include addition, deletion, substitution, inversion, duplication and translocation of bases.


★ CIE Specification Reference: - 6 Nucleic acids and protein synthesis: 6.2 Protein synthesis. b) state that a gene mutation is a change in the sequence of nucleotides that may result in an altered polypeptide. 16 Inherited change: 16.2 The roles of genes in determining the phenotype. e) explain that gene mutation occurs by substitution, deletion and insertion of base pairs in DNA and outline how such mutations may affect the phenotype.


★ Edexcel (Biology A – Salters-Nuffield) Specification Reference: - N/A.

★ Edexcel (Biology B) Specification Reference: - N/A.


★ OCR (Biology A) Specification Reference: - 6.1 Genetics and evolution. Types of gene mutations and their possible effects on protein production and function. To include substitution, insertion or deletion of one or more nucleotides. The possible effects of these gene mutations (i.e. beneficial, neutral or harmful).


★ OCR (Biology B) Specification Reference: - Module 5: Genetics, control and homeostasis 5.1.1 Patterns of inheritance. B) gene mutations (To include cystic fibrosis, sickle cell anaemia, phenylketonuria (PKU) and Huntington’s disease).


★ WJEC Specification Reference: - Continuity of Life 5. Inheritance (f) gene mutation as illustrated by sickle cell anaemia.


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