AP Biology Unit 5 Practice Test: Heredity

Topic 5.1 · Concept check

Which statement correctly describes the result of meiosis in a diploid organism?

Topic 5.1 · Concept check

When do homologous chromosomes separate, and when do sister chromatids separate?

Topic 5.1 · Apply it

A person with Down syndrome has three copies of chromosome 21. Which error during gamete formation can cause this?

Topic 5.2 · Data analysis

An organism has a diploid number of 6 (2n = 6). Ignoring crossing over, how many genetically different gametes can it make through independent assortment alone?

Topic 5.2 · Concept check

During which stage does crossing over occur, and what does it produce?

Topic 5.3 · Data analysis

Two plants heterozygous for two independently assorting genes are crossed (AaBb × AaBb). What fraction of the offspring is expected to be aabb?

Topic 5.3 · Data analysis

A student calculates chi-square to test whether the results fit a 3:1 ratio. The critical value for 1 degree of freedom at p = 0.05 is 3.84. Which conclusion is correct?

Topic 5.4 · Apply it

Red–green colour blindness is an X-linked recessive trait. A woman who is a carrier has children with a man who has normal colour vision. If they have a son, what is the probability that he is colour-blind?

Topic 5.4 · Data analysis

In a test cross, only 8% of offspring show recombinant combinations of two traits, instead of the 50% expected for independent assortment. What is the best explanation?

Topic 5.4 · Concept check

A disease is caused by a mutation in mitochondrial DNA. From which parent is a child most likely to inherit it?

Topic 5.5 · Apply it

Cuttings from one hydrangea plant are planted in soils with different pH. The flowers are blue in acidic soil and pink in alkaline soil. What does this show?

Topic 5.3 · Apply it

Two pea plants, both heterozygous for seed shape (Rr, where R for round is dominant), are crossed. What phenotype ratio is expected in the offspring?