Heredity: Crash Course Biology #9

Q: What is heredity?

A: Heredity is the passing on of traits from parents to offspring via genes.

Q: Who is Gregor Mendel and what is his contribution to genetics?

A: Gregor Mendel was an Austrian monk known as the father of genetics for his experiments with pea plants that led to the discovery of inheritance patterns.

Q: What are chromosomes and genes, and how do they relate to traits?

A: Chromosomes are structures in cells that contain genes, which are segments of DNA responsible for heredity and determining traits.

Q: What are polygenic traits, pleiotropic genes, and single gene traits?

A: Polygenic traits are controlled by multiple genes, pleiotropic genes influence multiple traits, and single gene traits are determined by one gene.

Q: Can you provide examples of Mendelian traits in humans?

A: Examples of Mendelian traits in humans include attached or detached earlobes, Hitchhiker's thumb, and tongue rolling.

Q: What is the role of alleles in determining traits?

A: Alleles are different forms of a gene, with dominant alleles masking the expression of recessive alleles in determining traits.

Q: How does allele inheritance demonstrate randomness?

A: Allele inheritance is random due to the independent assortment of chromosomes during meiosis, resulting in various combinations of alleles in offspring.

Q: Explain dominance and recessiveness in alleles using earwax as an example.

A: In earwax type, the wet allele (W) is dominant over the dry allele (w), leading to individuals with both WW and Ww genotypes having wet earwax.

Q: How are Punnett Squares used to determine phenotypes based on genotypes?

A: Punnett Squares are diagrams used to predict the possible genotypes and phenotypes of offspring based on the genotypes of the parents.

Q: What is the correlation between genes, traits, and phenotypes in individuals?

A: Genes determine traits, which in turn manifest as phenotypes in individuals, showcasing the direct relationship between genetics and observable characteristics.

Q: Can you explain the role of sex chromosomes in inheritance patterns in males and females?

A: Sex chromosomes determine the biological sex of an individual and influence the inheritance patterns of specific genetic traits that are located on the X and Y chromosomes.