BIOL 3301 EXAM QUESTIONS AND ANSWERS
LATEST UPDATE (GRADED A+)
Q: What are the key features of Mendel's single-factor crosses?
A: They involve one trait at a time, use true-breeding plants, and result in a 3:1 phenotype ratio in the F2
generation.
Q: What conclusions did Mendel draw from single-factor crosses?
A: Traits are determined by unit factors (genes) that exist in pairs, with dominant and recessive traits
segregating during gamete formation.
Q: What was the phenotypic ratio Mendel observed in two-factor crosses?
A: A 9:3:3:1 ratio in the F2 generation.
Q: How does a Punnett square help predict outcomes in genetic crosses?
A: It organizes potential gametes to visualize all possible genotypic and phenotypic combinations.
Q: What is the product rule in genetics?
A: The probability of two independent events occurring is the product of their individual probabilities.
Q: When is the chi-square test used in genetics?
A: To evaluate whether observed data fit an expected ratio or hypothesis.
Q: What is the principle of dominance?
A: In heterozygotes, one allele (dominant) masks the effect of the other (recessive).
Q: How do dihybrid crosses demonstrate the law of independent assortment?
A: They show that alleles for different traits segregate independently.
Q: What is the structural composition of a chromosome?
A: A chromosome consists of DNA and proteins, including histones, organized into chromatin.
Q: What does it mean for a species to be diploid?
A: Diploid organisms have two homologous sets of chromosomes, one from each parent.
Q: How do homologous chromosomes differ from sister chromatids?
A: Homologous chromosomes are similar but non-identical pairs, while sister chromatids are identical
copies.
Q: How does meiosis ensure genetic variation?
A: Through crossing over in prophase I and independent assortment during metaphase I.
LATEST UPDATE (GRADED A+)
Q: What are the key features of Mendel's single-factor crosses?
A: They involve one trait at a time, use true-breeding plants, and result in a 3:1 phenotype ratio in the F2
generation.
Q: What conclusions did Mendel draw from single-factor crosses?
A: Traits are determined by unit factors (genes) that exist in pairs, with dominant and recessive traits
segregating during gamete formation.
Q: What was the phenotypic ratio Mendel observed in two-factor crosses?
A: A 9:3:3:1 ratio in the F2 generation.
Q: How does a Punnett square help predict outcomes in genetic crosses?
A: It organizes potential gametes to visualize all possible genotypic and phenotypic combinations.
Q: What is the product rule in genetics?
A: The probability of two independent events occurring is the product of their individual probabilities.
Q: When is the chi-square test used in genetics?
A: To evaluate whether observed data fit an expected ratio or hypothesis.
Q: What is the principle of dominance?
A: In heterozygotes, one allele (dominant) masks the effect of the other (recessive).
Q: How do dihybrid crosses demonstrate the law of independent assortment?
A: They show that alleles for different traits segregate independently.
Q: What is the structural composition of a chromosome?
A: A chromosome consists of DNA and proteins, including histones, organized into chromatin.
Q: What does it mean for a species to be diploid?
A: Diploid organisms have two homologous sets of chromosomes, one from each parent.
Q: How do homologous chromosomes differ from sister chromatids?
A: Homologous chromosomes are similar but non-identical pairs, while sister chromatids are identical
copies.
Q: How does meiosis ensure genetic variation?
A: Through crossing over in prophase I and independent assortment during metaphase I.
