W08 Biology and Behaviour

1. Which mechanism does NOT contribute to genetic diversity among people?

• Crossing over

• Mutations

• Different nutritional levels in women during pregnancy

• Random assortment

2. In studies of rats, pups that receive more licking and grooming from their mothers show lower stress reactivity as adults. This is because maternal care affects the expression of the glucocorticoid receptor gene in the pups’ brains. What does this finding demonstrate?

• Environmental experiences can alter gene expression through epigenetic mechanisms such as DNA methylation, leading to long-term changes in behaviour.

• Only genes related to stress are affected by environmental factors.

• Maternal behaviour permanently changes the DNA sequence of the glucocorticoid receptor gene.

• The pups’ stress responses are determined entirely by their genotype and cannot be influenced by experience.

3. A person carries a Bb genotype for eye colour, where B = brown and b = blue. Which option correctly describes their genotype and phenotype?

• Genotype heterozygous and phenotype blue eyes

• Genotype homozygous dominant and phenotype brown eyes

• Genotype homozygous recessive and phenotype blue eyes

• Genotype heterozygous and phenotype brown eyes

4. Two biological parents both have brown hair, but each carries one recessive allele for blonde hair. This means both parents have the genotype Bb, where B = brown (dominant) and b = blonde (recessive). According to Mendelian inheritance patterns, if these two parents had 4 biological children together (all singleton births), on average how many would you expect to have blonde hair?

• 4 out of 4

• 2 out of 4

• 1 out of 4

• 3 out of 4

5. Which is considered the ideal behaviour genetics design?

• An adoptive twin study

• A monozygotic twin study

• The equal environments assumption

• A dizygotic twin study

6. What is the basic unit of heredity responsible for instructing the production of proteins?

• Genome

• Chromosome

• Gene

• Phenotype

7. Approximately what percentage of human DNA is made up of genes?

• 1%

• 10%

• 50%

• 99%

8. Which term describes the complete set of genetic material in an organism?

• Genotype

• Genome

• Gamete

• Allele

9. How many pairs of chromosomes does a typically developing human have?

• 46 pairs

• 20 pairs

• 23 pairs

• 12 pairs

10. What determines the biological sex of a child at conception?

• The egg cell from the mother

• The sperm cell from the father

• The mitochondrial DNA

• The random assortment of autosomes

11. Which cells have the ability to express all genes in the genome?

• Specialized liver cells

• Neurons

• Stem cells

• Gametes

12. What is the approximate number of protein-coding genes in humans?

• 100,000 - 150,000

• 2,000 - 3,000

• 20,000 - 21,000

• 500

13. Which process involves members of a chromosome pair swapping sections of DNA?

• Mutation

• Random assortment

• Crossing over

• Methylation

14. Why are X-linked recessive disorders more common in males (XY) than in females (XX)?

• The Y chromosome carries dominant alleles that cause these disorders.

• Males have more chromosomes than females.

• The Y chromosome is smaller and lacks matching alleles to override recessive alleles on the X chromosome.

• Males have higher mutation rates in their DNA.

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15. Polygenic inheritance refers to:

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• [ ] Traits determined by a single gene with two alleles.
  > This is Mend

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