Questions and Answers
What is the only way new alleles are created?
In which process does genetic variation primarily result from the mixing of pre-existing alleles?
Which type of mutation results in no effect on the protein produced?
What characteristic must a context chosen for an assessment demonstrate?
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How many total words should candidates aim for in their report?
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What type of mutation can create a new allele by altering the DNA base sequence?
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Which of the following contexts could be used to investigate genetic variation?
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During fertilization, which genetic aspect is established?
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What is the consequence of the sickle cell mutation in terms of haemoglobin?
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What type of allele is the mutated sickle cell allele classified as?
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Which genetic condition can arise due to the sickle cell mutation?
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How do the genotypes related to sickle cell disease differ from each other?
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Why is the sickle cell mutation still present in the population?
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What type of observational tool can be used to assess inheritance patterns of traits like sickle cell mutation?
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Which of the following describes the primary function of haemoglobin?
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What is a potential symptom of sickle cell anaemia?
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What is one of the primary mechanisms that contributes to genetic variation during meiosis?
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How many unique combinations of chromosomes can result from independent assortment during meiosis?
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Which of the following accurately describes segregation in the context of meiosis?
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In sexual reproduction, what results from the union of a random sperm and a random egg?
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What method allows for predicting possible offspring traits from two individuals mating?
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Which of the following represents a method for tracking genetic variation through generations?
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What is a significant limitation of using Punnett Squares in predicting offspring traits?
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Which process does NOT contribute to genetic variation in a population?
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Study Notes
Sources of Variation
- Variation arises from genetic mutations, meiosis, and fertilization.
- Mutations are permanent changes in DNA sequences, leading to new alleles.
- Meiosis produces gametes through processes that introduce variation.
Meiosis and Its Sources of Variation
- Crossing Over: Alleles are exchanged between homologous chromosomes, creating new allele combinations.
- Independent Assortment: Chromosomes align randomly during meiosis, enabling over 8 million possible gamete combinations.
- Segregation: Allele pairs are randomly separated, ensuring unique sperm and egg formation.
Fertilization
- Fertilization involves the random joining of sperm and egg to create a unique zygote, enhancing genetic diversity.
Gene Tracking
- Gene tracking identifies inherited genes across generations.
- Methods include:
- Pedigree Charts: Illustrate actual inheritance patterns.
- Gel Electrophoresis: Analyzes DNA fragments to determine genetic relationships.
- Punnett Squares: Predicts potential offspring ratios based on parental alleles, recognizing that real-life ratios can vary.
Sickle Cell Anemia Case Study
- Sickle Cell Anemia is a genetic disorder characterized by:
- Symptoms: Anaemia, pain, lethargy, blindness, organ dysfunction.
- Mutation in the haemoglobin gene affects oxygen transport.
- Patients' red blood cells change shape, forming sickle cells that can clog capillaries.
Sickle Cell Mutation Tracking
- The sickle cell allele (r) is recessive, leading to different genotypes (RR, Rr, rr) and phenotypes.
- Punnett Squares can calculate the likelihood of having the disease or being a carrier.
Persistence of Sickle Cell Mutation
- The mutation persists in populations due to advantages in malaria resistance for carriers, demonstrating natural selection.
Assessment Preparation
- Understanding genetic variation related to an identified characteristic is key for assessment.
- Candidates will write a report featuring two parts:
- Part A: Selection of a context with a single characteristic gene and known mutation (e.g., Sickle Cell Anemia).
- Part B: Response to a provided context, totaling approximately 800 words.
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Description
Explore the essential concepts of genetic variation, including sources such as mutations, meiosis, and fertilization. This quiz covers topics like crossing over, independent assortment, and gene tracking methods to test your understanding of how genetic diversity is achieved.
