CMU Genetics Week 2: Chapter 3 & 4 Practice Questions and Answers

CMU Genetics Week 2: Chapter 3 & 4 Practice Questions and Answers What is the distinctive pattern of inheritance found for X-linked recessive traits? a. Affects only males. b. Affected males have an affected father. c. Hemizygous males and homozygous females are affected. d. Mutant characters are combined. e. Affected individuals will always have an affected parent and an unaffected parent. - Ans:-c. Hemizygous males and homozygous females are affected. Which of the following statements is true about sex-linked traits? a. X-linked recessive genes are never expressed in males. ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 2/35 b. In general, males are affected by X-linked recessive disorders far more frequently than females. c.Fathers do not donate their Y chromosome to their sons. d. All of these statements are true. - Ans:-b. In general, males are affected by X-linked recessive disorders far more frequently than females. Congenital generalized hypertrichosis (CGH) is an X-linked dominant condition that produces dense hair on the face and upper body. What is the chance that a male affected by this condition will pass it on to his daughters (assume the mother is unaffected)? a. 0% b. 25% c. 50% d. 100% e. 75% - Ans:-D: 100% Which of the following trisomies is the least likely to lead to a live births? ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 3/35 Trisomy 21. Trisomy 13. Trisomy 18. Trisomy 1. All of these trisomies can lead to live births. - Ans:-Trisomy 1 Different versions of genes are called_____. Homologues Alleles ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 4/35 Autosomes Sister Chromatids Centromeres - Ans:-alleles Jacobs syndrome involves an extra Y chromosome (XYY) an extra X chromosome (XXX) a deletion of Y the chromosome ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 5/35 a deletion of X chromosome too many autosomal chromosomes - Ans:-an extra Y chromosome (XYY) Under what circumstances should a couple meet with a genetic counselor? if the woman will be over 35 years of age at the time of birth couples who are first cousins or other blood relatives couples who come from ethnic groups in which certain types of genetic defects are more common couples who have already had a child with a genetic disorder all of the these - Ans:-all of these ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 6/35 Which of the following properties is characteristic of an autosomal recessive pattern of inheritance? An important protein in the body is produced incorrectly or not at all. If both parents are affected then all children are affected. Male and female children are affected in roughly equal numbers. All of these are true. None of these are true. - Ans:-WRONG If both parents are affected then all children are affected. WRONG male and female children are affected in roughly equal numbers Individuals with Klinefelter's syndrome have XXY sex chromosomes. ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 7/35 True False - Ans:-True If a parent has an autosomal recessive trait then we know what about their children? (note: in this problem we do not know anything about the other parent) They must all have this trait as well None of them can have this trait This parent will not be able to have childr