Year 10 - Science
Mutations and genetic variants
DNA and the genome
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit covers the structure and function of eukaryotic and prokaryotic cells, DNA as the genetic material, and key genetic terms. It also explains protein synthesis, genetic variants, and how DNA structure affects proteins. The emphasis is on using models to explain scientific concepts.
Lesson Summary
You will learn to explain how mutations in DNA cause genetic variants.
Key Notes
- A change in the sequence of nucleotide bases in the DNA of the genome is called a mutation.
- Mutations can be caused by some substances and by ionising radiation.
- Most mutations are caused by errors when DNA is copied, when cells divide to make new cells.
- How substitution, insertion and deletion mutations change the base sequence in DNA.
- A mutation creates a genetic variant (a region of DNA in which the sequence of nucleotide bases has been changed).
Vocabulary To Learn
- DNA: DNA is a large chemical molecule made of smaller chemical groups. It carries the genetic code of all living organisms.
- nucleotide: Nucleotides are the chemical groups that are the building blocks of DNA. The four types are coded A, T, C and G.
- mutation: A mutation is a change in the nucleotide base sequence in the DNA of the genome.
- ionising radiation: Ionising radiation (e.g. X-rays, gamma rays and high-energy ultraviolet) can cause mutations in DNA.
- genetic variant: A genetic variant is produced when a mutation causes a change in the genetic sequence of a gene or a non-coding region of DNA.
Common Mistakes To Avoid
- Mixing up amino acids and nucleotides, also nucleotides and bases.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
A change in the sequence of nucleotide bases in the DNA of the genome is called a mutation. Mutations can be caused by some substances and by ionising radiation.
2. Define this scientific word and use it in context. 'DNA'
DNA is a large chemical molecule made of smaller chemical groups. It carries the genetic code of all living organisms. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: Mixing up amino acids and nucleotides, also nucleotides and bases. Correction: Activity checks: Nucleotides contain a base; DNA is a polymer of nucleotides that codes for the order of amino acids in a protein.
More Lessons In This Unit
- Genetic variants in genes can influence phenotype Study Guide
- Genetic variants in non-coding DNA can influence phenotype Study Guide
- Protein synthesis Study Guide
- The chemical structure of DNA Study Guide
- The genetic code Study Guide
- The genome Study Guide
- The genome, the environment and phenotype Study Guide
- The structure of DNA Study Guide
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