AP Biology Unit 5 practice questions: Heredity
8 original multiple-choice questions on AP Bio Unit 5, heredity. Answer each one in your browser and read the explanation, then review the key ideas below.
Question 1 of 8
Two heterozygous plants (Aa × Aa) are crossed. A is completely dominant. What phenotype ratio is expected in the offspring?
Question 2 of 8
Crossing over between homologous chromosomes happens during
Question 3 of 8
A woman who carries an X-linked recessive disorder has children with an unaffected man. What fraction of their sons are expected to have the disorder?
Question 4 of 8
Two plants heterozygous for two independently assorting genes (AaBb × AaBb) are crossed. What phenotype ratio is expected?
Question 5 of 8
In the cross AaBb × AaBb, what fraction of offspring are aabb?
Question 6 of 8
Nondisjunction during meiosis produces
Question 7 of 8
Why is a test cross done?
Question 8 of 8
Parents with blood types A (genotype Iᴬi) and B (genotype Iᴮi) have a child. What is the chance the child has type O blood?
Key ideas in Unit 5
- Meiosis makes haploid gametes; crossing over in prophase I and independent assortment create variation.
- Mendel's laws of segregation and independent assortment predict ratios: 3:1 for a monohybrid cross and 9:3:3:1 for a dihybrid cross.
- Use the multiplication rule for independent events and the addition rule for either-or outcomes.
- Non-Mendelian patterns include incomplete dominance, codominance, multiple alleles (ABO blood types), sex linkage and linked genes.
- Nondisjunction produces gametes with the wrong chromosome number.
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