HESI LPN
HESI Focus on Maternity Exam
1. Which of the following is most likely to develop sickle cell anemia?
- A. European American
- B. Native American
- C. African American
- D. Asian American
Correct answer: C
Rationale: Sickle cell anemia is most commonly found in individuals of African American descent. This is because sickle cell trait provides some protection against malaria, and historically, regions where malaria is or was prevalent have higher rates of sickle cell anemia. Therefore, individuals with African ancestry are at a higher risk of developing sickle cell anemia compared to other populations. Choices A, B, and D are less likely to develop sickle cell anemia due to lower genetic prevalence in their respective populations.
2. What determines a child’s sex?
- A. Presence of teratogens at the time of conception.
- B. Sex chromosome received from the mother.
- C. Presence of teratogens at the time of ovulation.
- D. Sex chromosome received from the father.
Correct answer: D
Rationale: The correct answer is the sex chromosome received from the father. The father contributes either an X or Y chromosome, which determines the child's sex. This occurs at the moment of fertilization when the sperm carrying either an X (resulting in a female) or Y (resulting in a male) chromosome fertilizes the egg. Choices A, B, and C are incorrect because the presence of teratogens at the time of conception or ovulation does not determine the child's sex. While the sex chromosome received from the mother is important, it is the father's contribution that ultimately determines the child's sex.
3. Which of the following statements about Rh incompatibility is true?
- A. Rh incompatibility occurs most commonly during a woman’s first pregnancy.
- B. Rh incompatibility is an untreatable condition that leaves a woman infertile for the rest of her life.
- C. Rh incompatibility is an abnormality that is transmitted from generation to generation and carried by a sex chromosome.
- D. Rh incompatibility occurs due to antibodies transmitted to a fetus during subsequent deliveries causing brain damage or death.
Correct answer: D
Rationale: Rh incompatibility occurs when the mother's antibodies attack the fetus's red blood cells, leading to serious complications, usually in subsequent pregnancies. Choice A is incorrect because Rh incompatibility often occurs in subsequent pregnancies, not necessarily the first one. Choice B is incorrect as Rh incompatibility does not render a woman infertile but can lead to complications during pregnancies. Choice C is incorrect as Rh incompatibility is not carried by a sex chromosome but involves the Rh factor on red blood cells.
4. Individuals with Klinefelter syndrome produce:
- A. less estrogen than normal males.
- B. less testosterone than normal males.
- C. less adenine than normal males.
- D. less thymine than normal males.
Correct answer: B
Rationale: Individuals with Klinefelter syndrome have an extra X chromosome (XXY), leading to reduced production of testosterone, the primary male sex hormone. This deficiency can result in various physical and developmental characteristics associated with the syndrome. Estrogen levels may actually be relatively elevated due to the imbalance between testosterone and estrogen. Choices C and D are incorrect as adenine and thymine are nucleotide bases found in DNA and are not related to hormone production.
5. Dizygotic (DZ) twins share _________ percent of their genes.
- A. 100
- B. 75
- C. 50
- D. 25
Correct answer: C
Rationale: Dizygotic (DZ) twins share approximately 50% of their genes. This is because dizygotic twins, also known as fraternal twins, originate from two separate fertilized eggs and share similar genetic similarity to regular siblings. Choice A (100%) is incorrect because if twins shared 100% of their genes, they would be identical twins (monozygotic). Choice B (75%) is incorrect as it is not the typical genetic similarity seen in dizygotic twins. Choice D (25%) is incorrect as it represents a significantly lower genetic similarity than what is observed in dizygotic twins.
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