BMST - Basic Math and Science Genetics and Heredity Questions and Answers Flashcards

A plant with genotype TtYy is crossed with a plant that is ttYy. What fraction of offspring will be tall and yellow (T_Y_)?

Answer: 3/8

Tt × tt gives 1/2 T_; Yy × Yy gives 3/4 Y_; multiplying gives 3/8 tall and yellow.

Which term describes the physical appearance or observable traits of an organism?

Answer: Phenotype

Phenotype refers to the observable characteristics of an organism, while genotype refers to its genetic makeup.

In humans, hemophilia A is an X-linked recessive disorder. A carrier mother and an unaffected father have children. What percentage of their sons will be affected?

Answer: 50%

A carrier mother (X^H X^h) passes the X^h allele to half her sons, so 50% of sons will be affected.

Two genes are said to be linked when they:

Answer: Are located on the same chromosome

Linked genes are located on the same chromosome and tend to be inherited together unless crossing over separates them.

A mother is blood type A (I^A i) and a father is blood type B (I^B i). What blood types are possible in their children?

Answer: A, B, AB, and O

The cross I^A i × I^B i produces I^A I^B (AB), I^A i (A), I^B i (B), and ii (O) offspring.

Which process during meiosis increases genetic variation by exchanging segments between homologous chromosomes?

Answer: Crossing over

Crossing over (recombination) occurs during prophase I of meiosis, shuffling alleles between homologous chromosomes.

A pedigree shows a trait that appears in every generation and affects both males and females equally. This pattern most likely indicates:

Answer: Autosomal dominant inheritance

A trait appearing every generation in both sexes without skipping is characteristic of autosomal dominant inheritance.