Biological Approach

Genetic inheritance

Section A Model Answer

Question

Explain how genetic inheritance influences one human behavior. [4]

Model Answer

Genetic inheritance refers to the process by which specific genotypes are passed from parents to offspring, providing a biological predisposition for certain behaviors or disorders. To investigate the extent of genetic influence, researchers compare concordance rates (the probability that two people with shared genes will both exhibit a trait) between monozygotic (MZ) twins and dizygotic (DZ) twins. A higher concordance in MZ twins suggests a stronger genetic component for that behavior. An example is the investigation of Major Depressive Disorder (MDD) through twin studies. Research has found that MZ twins have a significantly higher concordance rate for depression than DZ twins, often linking this vulnerability to variations in the 5-HTT gene. The higher concordance rate in MZ twins suggests that genetic inheritance contributes to the vulnerability to depression, although a rate below 100% indicates that environmental factors also play a critical role.

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Section B Model Answer

Scenario

The Master Scenario: "The Workspace Study" A university department designs a new "collaborative innovation hub" to improve student performance. The room features open seating, bright lighting, and digital whiteboards. Researchers observe that when students work in this specific environment, their problem-solving speed increases by 20%. However, they also notice that students from different cultural backgrounds use the space differently, and those who feel "out of place" in the high-tech setting often perform worse than they did in traditional libraries.

Question

To what extent could genetic inheritance explain why some students "thrive" while others "struggle" in the new workspace? [6]

Model Answer

Genetic inheritance involves the transmission of alleles from parent to offspring, creating a genotype that influences an individual's phenotype. Traits show varying degrees of heritability, meaning some students are more biologically sensitive to environments. In this scenario, performance may be linked to a genetic predisposition involving the 5-HTT gene. The "short" allele is associated with reduced serotonin transporter efficiency; this dysregulated signaling can heighten the emotional reaction to the "high-tech" setting, impairing the cognitive focus needed for puzzles. This explains the scenario by showing that genetic inheritance may predispose a student to environmental stress, explaining why only some students struggle.

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Exam Technique Guides

Overview

Section A vs Section B: Key Differences

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Section A

How to Write the Perfect Section A Response (4 marks)

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Section B

How to Write the Perfect Section B Response (6 marks)

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