Nursing Elites

1. Which of the following illnesses causes degeneration of the central nervous system?

• A. Tay-Sachs disease
• B. Cystic fibrosis
• C. Turner syndrome
• D. Klinefelter syndrome

Correct answer: A

Rationale: Tay-Sachs disease is a genetic disorder that causes a progressive degeneration of the central nervous system, particularly in infants. Choice B, Cystic fibrosis, is a genetic disorder that primarily affects the lungs and digestive system, not the central nervous system. Choices C and D, Turner syndrome and Klinefelter syndrome, are chromosomal disorders that do not directly involve degeneration of the central nervous system.

2. During which of the following periods does the development of arms and legs occur in a pregnancy?

• A. Development of the lungs
• B. Development of the heart
• C. Development of arms and legs
• D. Development of the stomach

Correct answer: C

Rationale: The correct answer is C. The development of arms and legs occurs during the critical period of the fourth to eighth weeks of pregnancy. This timeframe is crucial for the formation of limbs and other key body parts. Choices A, B, and D are incorrect because the development of the lungs, heart, and stomach respectively occurs at different stages of fetal development and is not primarily associated with the fourth to eighth weeks of pregnancy.

3. Do dizygotic (DZ) twins run in families?

• A. Yes
• B. No
• C. Rarely
• D. Never

Correct answer: A

Rationale: Yes, dizygotic (DZ) twins can run in families. This is due to genetic factors that influence hyperovulation, where a woman releases multiple eggs during her menstrual cycle. This genetic predisposition can be passed down through generations, increasing the likelihood of having dizygotic twins. Choices B, C, and D are incorrect because the statement that dizygotic twins run in families is true, as supported by scientific evidence. It is important to note that while the genetic predisposition for dizygotic twins can run in families, it does not guarantee that every generation will have twins, as other factors also play a role in twin pregnancies.

4. Tim, a 27-year-old man, has unusually narrow shoulders, low muscle mass, and has no facial and body hair. His doctor recently prescribed testosterone replacement therapy to him. Tim is most likely suffering from:

• A. Phenylketonuria (PKU).
• B. Cystic fibrosis.
• C. Klinefelter syndrome.
• D. Huntington’s disease (HD).

Correct answer: C

Rationale: Tim's physical characteristics, such as narrow shoulders, low muscle mass, and lack of facial and body hair, are typical signs of Klinefelter syndrome, a genetic condition where males have an extra X chromosome (XXY). This leads to underdeveloped testes and reduced testosterone production, resulting in features like gynecomastia, sparse facial and body hair, and reduced muscle mass. Testosterone replacement therapy is commonly used to address the hormonal imbalance in individuals with Klinefelter syndrome. Phenylketonuria (PKU) is a metabolic disorder unrelated to the symptoms described in Tim's case. Cystic fibrosis is a genetic respiratory condition that does not present with the physical characteristics mentioned. Huntington’s disease (HD) is a neurodegenerative disorder primarily affecting motor function and cognition, not physical appearance and muscle mass.

5. How many pairs of autosomes does a human zygote contain?

• A. 46
• B. 44
• C. 23
• D. 22

Correct answer: D

Rationale: A human zygote contains 22 pairs of autosomes and one pair of sex chromosomes, totaling 46 chromosomes. Therefore, the correct answer is 22. Choices A, B, and C are incorrect because they do not accurately represent the number of autosomes in a human zygote. Option A (46) represents the total number of chromosomes in a human zygote, not the number of autosomes. Option B (44) is incorrect as it does not account for the correct number of autosomes. Option C (23) is inaccurate since it represents the total number of chromosomes in a human gamete, not the number of autosomes in a zygote.

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