This checkpoint tests the opening block of the Genetics unit: introduction to genetics, DNA structure and function, replication, genes and alleles, inheritance patterns, and genetic variation through mutation.
This checkpoint combines the first five lessons. Strong performance means you can link DNA structure, gene function, inheritance and variation into a coherent explanation.
Introduction to genetics, heredity and variation. Key vocabulary: DNA, gene, chromosome, allele, trait.
DNA structure: double helix, nucleotides, base pairing (A-T, G-C). DNA stores genetic instructions.
DNA replication conceptually. Connection to cell division, growth, repair and reproduction.
Genes, alleles and inheritance patterns. Dominant and recessive traits, genotype and phenotype.
Genetic variation and mutations. Types of mutations and their effects on populations.
1. Which of the following best describes the structure of DNA?
2. In DNA, which bases pair together?
3. What is the main purpose of DNA replication before cell division?
4. What is the difference between a gene and an allele?
5. In a simplified pea-plant model, tall plants are produced by a dominant allele (T) and dwarf plants by a recessive allele (t). Which genotype would result in a dwarf plant?
6. Which statement about mutations is correct?
7. A scientist discovers a new species with very low genetic diversity. Which consequence is most likely?
8. Where are chromosomes found in a human cell?
9. Two tall pea plants produce a dwarf offspring (tt). If tall is dominant, what does this tell you about the parents' genotypes?
10. Which of the following is the best explanation for why sexual reproduction produces genetically different offspring?
11. Explain the relationship between DNA, genes and chromosomes. In your answer, describe what each structure is and how they are connected. 4 MARKS
12. A student states: "Mutations are always bad and should be prevented." Evaluate this statement using at least one example of a harmful mutation and one example of a beneficial or neutral mutation. 4 MARKS
13. The Tasmanian devil population has very low genetic diversity. Using your understanding of variation and inheritance, explain why this makes the species vulnerable to Devil Facial Tumour Disease (DFTD), and suggest why increasing genetic diversity might help conservation efforts. 4 MARKS
Use this section to identify what you have mastered and what needs more work before moving to Block B.
Confusing genes and alleles: A gene is a segment of DNA that can influence a characteristic; an allele is a version of that gene. In a simplified Mendelian model, T and t can represent two alleles of the same gene.
Thinking all mutations are harmful: Mutations can be harmful, beneficial or neutral. Without mutations, there would be no new genetic variation, and evolution could not occur.
Saying dominant means "stronger" or "more common": Dominant simply means the allele is expressed when only one copy is present. It has nothing to do with strength or frequency in the population.
Tick when you have finished all questions and reviewed your answers.