Nursing Elites

1. When both of the alleles for a trait, such as hair color, are the same, the person is said to be _____ for that trait.

• A. monozygous
• B. dizygous
• C. homozygous
• D. hemizygous

Correct answer: C

Rationale: A person is homozygous for a trait when they have two identical alleles for that trait. In this case, both alleles are the same, indicating a homozygous genotype. Choice A, 'monozygous,' is incorrect as it refers to identical twins originating from a single fertilized egg. Choice B, 'dizygous,' is also incorrect as it refers to fraternal twins or individuals that develop from two separate fertilized eggs. Choice D, 'hemizygous,' is incorrect because it describes a genetic condition where only one allele is present in a diploid organism, typically related to genes on the sex chromosomes.

2. Rubella, also called German measles, is a viral infection passed from the mother to the fetus that can cause birth defects such as deafness, intellectual disabilities, blindness, and heart disease in the embryo.

• A. Rubella
• B. Syphilis
• C. Cystic fibrosis
• D. Phenylketonuria

Correct answer: A

Rationale: Rubella, also known as German measles, is a viral infection that can lead to severe birth defects when contracted by a mother during pregnancy. Rubella is the correct answer because it is specifically associated with causing birth defects such as deafness, intellectual disabilities, blindness, and heart disease in the embryo. Syphilis (Choice B) can be passed from mother to fetus but does not cause the mentioned birth defects associated with Rubella. Cystic fibrosis (Choice C) and Phenylketonuria (Choice D) are genetic conditions and not infections transmitted from mother to fetus, making them incorrect choices in this context.

3. 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.

4. 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.

5. Which of the following processes happen during mitosis?

• A. Strands of deoxyribonucleic acid (DNA) break apart.
• B. Adenine combines with its appropriate partner, cytosine.
• C. Sperm and ova cells are created.
• D. Twenty-three chromosomes are created.

Correct answer: A

Rationale: The correct process that happens during mitosis is the breaking apart, replication, and division of DNA strands into two new cells, each with the same number of chromosomes as the original cell. Choice B is incorrect because it describes base pairing in DNA, not a process specific to mitosis. Choice C is incorrect as the creation of sperm and ova cells is related to meiosis, not mitosis. Choice D is incorrect because chromosomes are not created during mitosis; they are replicated and divided equally between the daughter cells.

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