Nursing Elites

1. Which of the following statements is true of a sperm cell?

• A. A sperm cell is significantly larger than an egg cell.
• B. A sperm cell contains two Y chromosomes.
• C. A sperm cell travels randomly inside a woman’s reproductive tract.
• D. A sperm cell is one of the smallest types of cells in the body.

Correct answer: D

Rationale: The correct answer is D. A sperm cell is indeed one of the smallest cells in the human body, much smaller than an egg cell. Choice A is incorrect as sperm cells are much smaller than egg cells. Choice B is incorrect because a sperm cell carries either an X or a Y chromosome, not two Y chromosomes. Choice C is incorrect since sperm cells move in a purposeful manner guided by various factors within a woman's reproductive tract, not randomly.

2. Most victims of _____ die of respiratory infections in their 20s.

• A. Tay-Sachs disease
• B. cystic fibrosis
• C. Turner syndrome
• D. Klinefelter syndrome

Correct answer: B

Rationale: Individuals with cystic fibrosis have a genetic disorder that causes mucus to be thick and sticky, leading to blockages in the lungs and digestive system. This mucus buildup makes them more susceptible to severe respiratory infections, which can ultimately result in premature death in their 20s. Tay-Sachs disease (Choice A) is a genetic disorder that affects the nervous system, not typically causing respiratory infections. Turner syndrome (Choice C) and Klinefelter syndrome (Choice D) are chromosomal disorders that do not directly lead to the respiratory issues observed in cystic fibrosis.

3. Before meiosis, a sperm cell:

• A. contains 46 chromosomes.
• B. contains two X chromosomes.
• C. is significantly larger than an egg cell.
• D. contains both an X and a Y chromosome.

Correct answer: A

Rationale: Before meiosis, a sperm cell contains 46 chromosomes. This is because sperm cells, like other somatic cells, have a diploid number of chromosomes. During meiosis, the number of chromosomes is halved to 23 to combine with an egg cell during fertilization. Choice B is incorrect because a sperm cell carries either an X or a Y chromosome, not both (Choice D). Choice C is incorrect as sperm cells are generally smaller than egg cells, which is an adaptation that aids in motility and penetration of the egg during fertilization.

4. Which field of biology studies heredity?

• A. Etiology.
• B. Ecology.
• C. Genetics.
• D. Eugenics.

Correct answer: C

Rationale: Genetics is the branch of biology that focuses on the study of heredity and variation in organisms. Etiology (choice A) deals with the causes of diseases, not heredity. Ecology (choice B) is concerned with the relationships between organisms and their environment, not specifically heredity. Eugenics (choice D) is a controversial field that involves improving the genetic quality of the human population through selective breeding, which is different from the study of heredity itself.

5. In the structure of deoxyribonucleic acid (DNA), which of the following bases combines with thymine?

• A. Cytosine
• B. Adenine
• C. Rhodamine
• D. Serine

Correct answer: B

Rationale: The correct answer is B: Adenine. In the structure of DNA, adenine pairs with thymine through hydrogen bonding, forming one of the complementary base pairs that make up the double helix structure of DNA. Cytosine pairs with guanine, not thymine. Rhodamine and serine are not DNA bases and do not participate in DNA base pairing. Therefore, choices A, C, and D are incorrect.

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