Question 1:

Which of the following is a genetic disorder caused by an abnormal number of sex chromosomes?

Explanation: Turner syndrome is a genetic disorder caused by the presence of only one X chromosome in females (X0). It is an example of a genetic disorder caused by an abnormal number of sex chromosomes. Therefore, option B is correct.

Question 2:

Which of the following inheritance patterns is characteristic of autosomal recessive disorders?

Explanation: Autosomal recessive disorders can affect males and females. They are characterized by the presence of two copies of the mutated gene (one inherited from each parent) for the disorder to manifest. Therefore, option D is correct.

Question 3:

Which of the following genetic disorders is caused by a mutation in the CFTR gene?

Explanation: Cystic fibrosis is caused by a mutation in the CFTR gene. This gene encodes a protein involved in the regulation of salt and water movement across cell membranes. Therefore, option D is correct.

Question 4:

Which of the following inheritance patterns is characteristic of X-linked recessive disorders?

Explanation: X-linked recessive disorders primarily affect males. They are caused by mutations in genes located on the X chromosome. The inheritance of these disorders follows a pattern of passing the mutation from carrier females to affected males. Therefore, option A is correct.

Question 5:

Which of the following is an example of a chromosomal disorder caused by the presence of an extra copy of chromosome 21?

Explanation: Down syndrome, also known as trisomy 21, is caused by the presence of an extra copy of chromosome 21. This genetic disorder is characterized by intellectual disability and certain physical features. Therefore, option A is correct.