List of top Biology Questions on Mendelian Disorders

Which of the following is a dominant autosomal disorder?

Match the following chromosomal abnormalities with their correct definitions: \[ \begin{array}{|c|c|} \hline \text{Chromosomal Abnormality} & \text{Definition} \\ \hline 1. \text{Monosomy} & D. \text{Presence of only one copy of a particular chromosome} \\ \hline 2. \text{Nullisomy} & B. \text{Absence of both homologous chromosomes} \\ \hline 3. \text{Trisomy} & A. \text{Presence of three copies of a particular chromosome} \\ \hline 4. \text{Tetrasomy} & C. \text{Presence of four copies of a particular chromosome} \\ \hline \end{array} \]

In a family, a man with hemophilia, a genetic disorder where blood doesn't clot properly, marries a woman who is a carrier of the gene but does not express the disorder. What is the probability that their son will have hemophilia?

Phenylketonuria is caused by: