according to a study in 2014 by skakkebaek et al who among the following is most likely to have gynecomastia

HESI LPN

HESI Maternal Newborn

1. According to a study in 2014 by Skakkebaek et al., who among the following is most likely to have gynecomastia?

A. Jennifer, a dancer, who has Down syndrome
B. Frank, a teacher, who is diagnosed with XYY syndrome
C. Peter, a fashion designer, who has Klinefelter syndrome
D. Ria, a gym instructor, who is diagnosed with Turner syndrome

Correct answer: C

Rationale: Individuals with Klinefelter syndrome have an extra X chromosome (XXY) and typically have reduced testosterone levels, which can lead to gynecomastia (enlarged breasts). This condition is not usually associated with Down syndrome (choice A), XYY syndrome (choice B), or Turner syndrome (choice D), making them less likely to have gynecomastia.

2. Humans begin life as a single cell that divides repeatedly. This cell is known as a(n):

A. zygote.
B. gonadotrope.
C. embryo.
D. chromaffin.

Correct answer: A

Rationale: A zygote is the correct answer. It is the initial cell formed when a sperm cell fertilizes an egg cell, marking the beginning of human development. Choice B, gonadotrope, is incorrect as it refers to a type of hormone-secreting cell in the pituitary gland. Choice C, embryo, is incorrect as it is the stage of development after the zygote has implanted into the uterine wall and undergone initial cell divisions. Choice D, chromaffin, is incorrect as it refers to cells found in the adrenal medulla that produce and store catecholamines.

3. Which of the following statements is true of Down’s syndrome?

A. Down’s syndrome is usually caused by an extra copy of chromosome 21 in an individual.
B. The symptoms of Down’s syndrome are similar to those of sickle-cell anemia.
C. Down’s syndrome is caused by a sexually transmitted infection (STI) during conception.
D. The probability of having a child with Down’s syndrome increases with the age of the parents.

Correct answer: D

Rationale: The correct answer is D. The likelihood of having a child with Down’s syndrome increases as the age of the parents increases, particularly the mother's age. Choice A is incorrect because Down’s syndrome is caused by an extra copy of chromosome 21, not a defect in the sex chromosomes. Choice B is incorrect as the symptoms of Down’s syndrome and sickle-cell anemia are different. Choice C is also incorrect as Down’s syndrome is not caused by a sexually transmitted infection during conception.

4. Matt is a 36-year-old male. In the past year, he has noticed that his limbs sometimes move on their own, and he has also started having trouble remembering things and doing simple calculations. Matt’s father and grandfather were also known to have similar problems during their adulthood. Matt is most likely suffering from:

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

Correct answer: D

Rationale: Matt is exhibiting symptoms typical of Huntington’s disease (HD), a hereditary condition characterized by involuntary movements, cognitive impairment, and behavioral changes. The fact that Matt's father and grandfather had similar issues supports the genetic nature of the disease. Phenylketonuria (PKU) is a metabolic disorder that affects amino acid metabolism, not presenting with the symptoms described. Cystic fibrosis primarily affects the respiratory and digestive systems, not causing the neurological symptoms described. Turner syndrome is a genetic condition affecting females and is not associated with the symptoms described in the case of Matt.

5. Chromosomes are _____ structures found in cells.

A. rod-shaped
B. circular
C. cone-shaped
D. octagonal

Correct answer: A

Rationale: Chromosomes are rod-shaped structures that carry genetic information in the form of DNA. They are typically seen as elongated structures when visualized under a microscope. Choice B, circular, is incorrect as chromosomes do not have a circular shape; they are linear. Choice C, cone-shaped, is not accurate as chromosomes do not resemble cones in any way. Choice D, octagonal, is also incorrect as chromosomes do not have an octagonal appearance. Therefore, the correct answer is A, rod-shaped, which accurately describes the shape of chromosomes.