Monohybrid inheritance：練習題

What is the correct biological definition of an allele?

A woman with blood group AB has a child with a man who has blood group A. Which blood group cannot be present in any of their offspring?

A woman is a carrier for the sex-linked recessive condition hemophilia (\(X^H X^h\)). If she has a son with a man who does not have hemophilia (\(X^H Y\)), what is the probability that this son will have the condition?

Which term describes the observable features of an organism resulting from its genetic make-up and its environment?

What is the main purpose of performing a test cross in monohybrid inheritance?

Using the terms dominant and recessive, explain why an individual with the genotype \(Bb\) displays the same phenotype as an individual with the genotype \(BB\).

In a species of plant, the allele for tall stems (\(T\)) is dominant to the allele for short stems (\(t\)). Calculate the phenotypic ratio of offspring produced from a cross between a heterozygous plant (\(Tt\)) and a homozygous recessive plant (\(tt\)).

A man with blood group AB and a woman with blood group O have a child. Calculate the percentage probability that the child will have blood group B.

In a species of pea plant, the allele for purple flowers (P) is dominant over the allele for white flowers (p). A scientist crosses two plants to study the inheritance of flower color.

(a) Define the term genotype.
(b) A plant has the genotype \(Pp\). State whether this plant is homozygous or heterozygous and identify its phenotype.
(c) If this \(Pp\) plant is allowed to self-pollinate, identify the two types of gametes it can produce.

In humans, the sex of an individual is determined by the inheritance of sex chromosomes (X and Y).

(a) Identify the genotype of a human male and a human female regarding their sex chromosomes.
(b) Provide a Punnett square to show the possible genotypes of the offspring produced when a male and a female reproduce.
(c) Using your Punnett square, explain why the probability of a couple having a male child is always \(50\%\). Support your answer by mentioning the gametes produced by the father.