Nursing Elites

1. Chromosomes contain thousands of segments called:

• A. nuclei.
• B. nodes.
• C. capillaries.
• D. genes.

Correct answer: D

Rationale: Chromosomes are structures composed of DNA and genes. Genes are the functional segments within chromosomes that encode specific traits and characteristics. The other choices ('nuclei,' 'nodes,' 'capillaries') do not accurately describe the segments found within chromosomes and are unrelated to their structure or function.

2. Once the testes have developed in the embryo, they begin to produce male sex hormones, or _____.

• A. androgens
• B. genotypes
• C. blastocysts
• D. teratogens

Correct answer: A

Rationale: Androgens are male sex hormones, such as testosterone, produced by the testes after they have developed in the embryo. Androgens are responsible for the development of male secondary sexual characteristics. Genotypes refer to an individual's genetic makeup, not hormones. Blastocysts are early stage embryos, not male sex hormones. Teratogens are substances that can interfere with fetal development, not male sex hormones produced by the testes.

3. If an individual receives a recessive gene for eye color from both parents, the:

• A. gender of the child will not determine the expression of that trait.
• B. recessive trait will be expressed in the child.
• C. recessive trait will be expressed in all the offspring.
• D. recessive trait will be suppressed, and the dominant trait will not be expressed.

Correct answer: B

Rationale: When an individual inherits a recessive gene for eye color from both parents, the recessive trait will be expressed in the child. This is because having two copies of the recessive gene overrides the presence of any dominant gene. Choice A is incorrect because the expression of the trait is determined by the genetic makeup, not the gender of the child. Choice C is incorrect as the expression of the recessive trait is certain when both parents pass on the recessive gene, but it does not mean that all offspring will express the trait. Choice D is incorrect because if both parents provide a recessive gene, the dominant trait will not be expressed in the child, but it does not mean it will be suppressed; rather, the recessive trait will be expressed.

4. Does the probability of having a child with Down’s syndrome increase with the age of the parents?

• A. TRUE
• B. FALSE
• C. Sometimes
• D. Never

Correct answer: A

Rationale: The correct answer is A: TRUE. Advanced parental age, particularly maternal age, is associated with an increased risk of Down's syndrome in offspring. As parents get older, the likelihood of having a child with Down's syndrome increases. Choices B, C, and D are incorrect because the risk of Down's syndrome is known to rise with parental age, especially maternal age, due to the increased likelihood of chromosomal abnormalities during egg formation.

5. Which of the following pairs of bases is present in the rungs of the ladder-like structure of deoxyribonucleic acid (DNA)?

• A. Cytosine with guanine.
• B. Rhodamine with biotin.
• C. Diaminopurine with ribozyme.
• D. Serine with tyrosine.

Correct answer: A

Rationale: The correct answer is A: Cytosine with guanine. In the DNA double helix, cytosine always pairs with guanine forming a base pair, and adenine pairs with thymine. These complementary base pairs form the rungs of the ladder-like structure of DNA. Choice B, Rhodamine with biotin, is incorrect as they are not base pairs found in DNA. Choice D, Serine with tyrosine, is incorrect as they are amino acids, not DNA bases. Choice C, Diaminopurine with ribozyme, is also incorrect as ribozyme is an enzyme, not a base, and diaminopurine is not one of the standard bases found in DNA.

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