Question 1: In a dihybrid cross between two heterozygous pea plants (AaBb x AaBb), what is the expected phenotypic ratio of the offspring assuming complete dominance?

Answer: 9:3:3:1

Question 2: Define polygenic inheritance and give an example of a trait influenced by it.

Answer: Polygenic inheritance is when multiple genes influence a single trait, resulting in a continuous range of phenotypes; an example is human skin color.

Question 3: What is the difference between homozygous and heterozygous genotypes? Provide an example of each.

Answer: Homozygous means having two identical alleles for a gene (e.g., AA or aa), while heterozygous means having two different alleles (e.g., Aa).

Question 4: In humans, attached earlobes are recessive to free earlobes. If two heterozygous individuals mate, what is the probability that their child will have attached earlobes?

Answer: 25%

Question 1: Describe how a point mutation can affect a protein. Provide an example of a disease caused by such a mutation.

Answer: A point mutation changes a single nucleotide, which can alter the amino acid sequence of a protein, potentially disrupting its function; sickle cell anemia is caused by a point mutation in the hemoglobin gene.

Question 2: Explain the difference between silent, missense, and nonsense mutations.

Answer: Silent mutations do not change the amino acid; missense mutations result in a different amino acid; nonsense mutations create a premature stop codon, truncating the protein.

Question 1: A mother with type AB blood and a father with type O blood have a child. What are the possible blood types of the child?

Answer: A or B

Question 2: Explain how a recessive genetic disorder can skip generations within a family.

Answer: Recessive disorders can skip generations because individuals must inherit two copies of the mutated gene (homozygous recessive) to express the disorder; carriers with only one copy do not show symptoms.

Question 3: If a heterozygous carrier of cystic fibrosis mates with an unaffected individual, what is the probability their child will have cystic fibrosis?

Answer: 25%