Nursing Elites

1. What is the typical sex chromosome pattern for males?

• A. XX
• B. XYY
• C. XY
• D. XXY

Correct answer: C

Rationale: The correct answer is C: XY. In males, the typical sex chromosome pattern consists of one X chromosome and one Y chromosome. Choice A (XX) is the sex chromosome pattern for females. Choice B (XYY) is a chromosomal disorder where males have an extra Y chromosome. Choice D (XXY) is the sex chromosome pattern associated with Klinefelter syndrome, a condition where males have an extra X chromosome.

2. Twenty-year-old Jack is extremely tall and has very thick facial hair. Most of his male secondary sex characteristics are also more pronounced than men of his age. In this scenario, Jack is most likely:

• A. an XYY male.
• B. diagnosed with Klinefelter syndrome.
• C. an XXY male.
• D. diagnosed with Down syndrome.

Correct answer: A

Rationale: The correct answer is A: an XYY male. Individuals with XYY syndrome often exhibit increased height and more pronounced secondary male characteristics, such as thick facial hair. Choice B, Klinefelter syndrome (XXY), typically presents with less prominent male secondary sex characteristics due to the presence of an extra X chromosome. Choice C, XXY male, refers to Klinefelter syndrome, which does not align with the description of Jack having more pronounced male secondary sex characteristics. Choice D, Down syndrome, is caused by a trisomy of chromosome 21 and is not associated with the physical characteristics described in the scenario.

3. What causes Down's syndrome?

• A. Alcohol abuse by the mother at the time of conception.
• B. Sex-linked chromosomal abnormalities.
• C. An extra chromosome on the 21st pair.
• D. Drug abuse by the mother during pregnancy.

Correct answer: C

Rationale: Down's syndrome, also known as trisomy 21, is caused by the presence of an extra chromosome on the 21st pair. Choice A is incorrect as alcohol abuse is not the cause of Down's syndrome. Choice B is incorrect because Down's syndrome is not related to sex-linked chromosomal abnormalities. Choice D is also incorrect as drug abuse by the mother during pregnancy is not the cause of Down's syndrome.

4. What is the central layer of the embryo from which the bones and muscles develop?

• A. neural tube
• B. mesoderm
• C. ectoderm
• D. umbilical cord

Correct answer: B

Rationale: The correct answer is mesoderm. The mesoderm is the middle layer of the embryo that gives rise to the bones, muscles, and other connective tissues. The neural tube (choice A) develops into the nervous system, not bones and muscles. The ectoderm (choice C) forms the skin and nervous system, not bones and muscles. The umbilical cord (choice D) is a structure that connects the developing fetus to the placenta; it is not a layer of the embryo that gives rise to bones and muscles.

5. What term is used to describe each member of a pair of genes?

• A. allele
• B. zygote
• C. autosome
• D. node

Correct answer: A

Rationale: The correct answer is 'allele.' An allele refers to one of two or more versions of a gene located at the same position on a chromosome. In genetics, alleles are responsible for variations in inherited traits. Choice B, 'zygote,' is incorrect as a zygote is a fertilized egg cell formed by the fusion of two gametes. Choice C, 'autosome,' is incorrect as autosomes are non-sex chromosomes that determine an individual's genetic traits excluding sex-linked characteristics. Choice D, 'node,' is incorrect as it does not relate to the concept of genes or genetic inheritance.

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