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Medical Genetics 4th Edition by Lynn B. Jorde -Test Bank

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Chapter 2: Basic Cell Biology: Structure and Function of Genes and Chromosomes

Multiple Choice

 

1. Mutation in fibroblast growth factor receptor 3 (FGFR3)
2. Retinoblastoma
3. Achondroplasia
4. Neurofibromatosis type 1
5. Huntington disease
6. Marfan syndrome

 

Answer: b

 

Correct Feedback: b. Mutations in the fibroblast growth factor receptor 3 do cause achondroplasia.

 

Incorrect Feedback: a. Retinoblastoma is caused by mutations in a tumor suppressor on chromosome 13.

1. Neurofibromatosis type one is caused by a mutation of the neurofibromin gene (which may act as a tumor suppressor) on chromosome 17q
2. Huntington disease is caused by a CAG expanded repeat on the distal tip of chromosome 4p.
3. Marfan patients have mutations of the chromosome 15 gene encoding fibrillin, a connective tissue protein.

 

2. Abnormal binding of gene product to GAPDH (enzyme involved in glycolysis)
3. Retinoblastoma
4. Achondroplasia
5. Neurofibromatosis type 1
6. Huntington disease
7. Marfan syndrome

 

Answer: d

 

Correct Feedback: d. This is a characteristic of Huntington disease.

 

Incorrect Feedback: a. Retinoblastoma is caused by mutations in a tumor suppressor on chromosome 13.

1. Mutations in the fibroblast growth factor receptor 3 cause achondroplasia.
2. Neurofibromatosis type one is caused by a mutation of the neurofibromin gene (which may act as a tumor suppressor) on chromosome 17q
3. Marfan patients have mutations of the chromosome 15 gene encoding fibrillin, a connective tissue protein.

 

3. phosphorylation of gene product by cyclin-dependent kinases (CDK); binding of gene product to transcription factors such as E2F
4. Retinoblastoma
5. Achondroplasia
6. Neurofibromatosis type 1
7. Huntington disease
8. Marfan syndrome

 

Answer: a

Correct Feedback: a. The retinoblastoma gene product is phosphorylated by a CDK and then binds to transcription factors.

 

Incorrect Feedback: b. Mutations in the fibroblast growth factor receptor 3 cause achondroplasia.

1. Neurofibromatosis type one is caused by a mutation of the neurofibromin gene (which may act as a tumor suppressor) on chromosome 17q
2. Huntington disease involves abnormal binding of gene product to GAPDH (enzyme involved in glycolysis)
3. Marfan patients have mutations of the chromosome 15 gene encoding fibrillin, a connective tissue protein.

 

4. Mutations in fibrillin gene
5. Retinoblastoma
6. Achondroplasia
7. Neurofibromatosis type 1
8. Huntington disease
9. Marfan syndrome

 

Answer: e

 

Correct Feedback: e. Marfan patients have mutations of the chromosome 15 gene encoding fibrillin, a connective tissue protein.

 

Incorrect Feedback: a. The retinoblastoma gene product is phosphorylated by a CDK and then binds to transcription factors.

1. Mutations in the fibroblast growth factor receptor 3 cause achondroplasia.
2. Neurofibromatosis type one is caused by a mutation of the neurofibromin gene (which may act as a tumor suppressor) on chromosome 17q
3. Huntington disease involves abnormal binding of gene product to GAPDH (enzyme involved in glycolysis)

 

5. Which of the following could produce an XY female?
6. Deletion of the Sry gene
7. Point mutation in the Sry gene
8. Translocation of the Sry gene to the X chromosome during meiosis in the father
9. None of the above
10. All of the above

 

Answer: e

 

Correct Feedback: e. All of the above could produce an XY female.

 

Incorrect Feedback: a. This is true, but it is not the only true answer.

1. This is true, but it is not the only true answer.
2. This is true, but it is not the only true answer.
3. There are true answers.

 

6. Which of the following is not a characteristic of cystic fibrosis?
7. Chloride channel defect
8. Hyperabsorption of intracellular sodium
9. Elevated sweat chloride
10. Fibrous ovarian cysts
11. Pancreatic insufficiency

 

Answer: d

 

Correct Feedback: This is not a characteristic of cystic fibrosis.

 

Incorrect Feedback: This is a characteristic of cystic fibrosis.

 

7. Each of the following chromosome abnormalities involves a 20 megabase region of the long arm of chromosome 5 (5q). Which abnormality is most likely to cause severe disease?
8. Deletion of the region
9. Duplication of the region
10. A balanced translocation involving the region (i.e., in the translocation carrier)
11. Pericentric inversion
12. Paracentric inversion

 

Answer: a

 

Correct Feedback: This is the most likely to cause severe disease.

 

Incorrect Feedback: This can cause problems, but they are not as likely to be as severe as a deletion of the entire gene.

 

8. Which of the following diseases is a good example of locus heterogeneity?
9. Prader-Willi syndrome
10. Myotonic dystrophy
11. Osteogenesis imperfecta
12. Duchenne muscular dystrophy
13. Hemophilia A

 

Answer: c

 

Correct Feedback: c. Locus heterogeneity is where genes have more than on discernible effect. OI effects bones, teeth, and sclera.

 

Incorrect Feedback: a. Prader-Willi syndrome is a good example of genomic imprinting.

1. Myotonic dystrophy is a good example of anticipation.
2. Duchenne muscular dystrophy is an X-linked disease.
3. Hemophilia A is an X-linked disease.

 

9. Why are some autosomal dominant disorders (e.g., Marfan syndrome) seen more commonly in the offspring of older fathers?
10. Replication errors accumulate as sperm-producing stem cells continue to divide
11. Rate of nondisjunction increases in older males
12. Recombination rates increase in older males
13. All spermatocytes are produced during male embryonic development, so older males produce older sperm cells
14. None of the above

 

Answer: a

 

Correct Feedback: a. This is why some autosomal dominant disorders are seen more commonly in the offspring of older fathers.

 

Incorrect Feedback: b. This is seen in older mothers.

1. This is not true.
2. This is not true.
3. There is a correct answer

 

10. A woman with phenotypically normal parents has two brothers with Duchenne muscular dystrophy. She experiences mild muscle weakness in her legs. Which of the following mechanisms is most likely to be directly involved?
11. Germline mosaicism
12. Skewed X inactivation
13. Mutation near the pseudoautosomal region of the Y chromosome
14. New mutation in this woman
15. Nondisjunction of her mother’s X chromosomes

 

Answer: b

 

Correct Feedback: b. This is most likely to be directly involved.

 

Incorrect Feedback: a. This wouldn’t explain why a heterotroph would manifest the disease.

1. A female would not have a Y chromosome.
2. If this were the case it would be unlikely that her brothers had the disease.
3. Duchenne muscular dystrophy is not a chromosomal disease.

 

11. Consider a fetus affected with one of the following conditions. For which condition is spontaneous loss during pregnancy most likely?
12. Down syndrome
13. Neurofibromatosis type 1
14. Retinoblastoma
15. Huntington disease
16. Trisomy 18

 

Answer: e

 

Correct Feedback: e. Chromosomal abnormalities are the number one cause of fetal loss, and trisomy 18 is less compatable with survival than trisomy 21.

 

Incorrect Feedback: a. Chromosomal abnormalities are the number one cause of fetal loss, but trisomy 18 is less compatable with survival than trisomy 21

1. Chromosomal abnormalities are the number one cause of fetal loss.
2. Chromosomal abnormalities are the number one cause of fetal loss.
3. Chromosomal abnormalities are the number one cause of fetal loss.