Nursing Elites

1. What causes cystic fibrosis?

• A. Sex-linked abnormality.
• B. Abnormality in the 21st pair of chromosomes.
• C. Recessive gene.
• D. Single segment found only on the Y chromosome.

Correct answer: C

Rationale: Cystic fibrosis is a genetic disorder caused by inheriting two copies of a recessive gene, one from each parent. This means that both parents must carry at least one copy of the faulty gene for a child to inherit the condition. Choice A is incorrect because cystic fibrosis is not linked to the sex chromosomes. Choice B is incorrect as cystic fibrosis is not caused by an abnormality in the 21st pair of chromosomes but by a specific gene mutation. Choice D is also incorrect as cystic fibrosis is not related to the Y chromosome, which is specific to males.

2. Which of the following statements is a symptom of cystic fibrosis in children?

• A. Cystic fibrosis leads to uncontrollable muscle movements and personality changes.
• B. Cystic fibrosis leads to the excessive production of thick mucus that clogs the pancreas and lungs.
• C. Cystic fibrosis causes red blood cells to clump together, obstructing small blood vessels and decreasing the oxygen supply.
• D. Cystic fibrosis causes the central nervous system to degenerate, resulting in death.

Correct answer: B

Rationale: The correct answer is B. Cystic fibrosis is a genetic disorder that causes the body to produce thick, sticky mucus. This mucus can clog the airways in the lungs and obstruct the pancreas, leading to severe respiratory and digestive problems. Choice A is incorrect because uncontrollable muscle movements and personality changes are not typical symptoms of cystic fibrosis. Choice C is incorrect because cystic fibrosis does not directly cause red blood cells to clump together and obstruct small blood vessels. Choice D is incorrect because cystic fibrosis primarily affects the respiratory and digestive systems, not the central nervous system.

3. 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.

4. Which of the following statements is true of menstruation?

• A. During this time, the endometrium is shed.
• B. During this time, an unfertilized egg is discharged.
• C. During this time, a female can engage in sexual activity with her partner.
• D. During this time, a fertilized egg implants in the uterine lining.

Correct answer: B

Rationale: The correct statement regarding menstruation is that during this time, an unfertilized egg is discharged along with the shedding of the uterine lining. Choice A is incorrect because the endometrium is shed during menstruation. Choice C is incorrect as menstruation does not prevent a female from engaging in sexual activity with her partner. Choice D is incorrect as a fertilized egg does not undergo mitosis during menstruation but rather implants in the uterine lining for further development.

5. Which of the following statements is true of mutations?

• A. Mutations can only occur by chance.
• B. Mutations produce sperm and ova cells.
• C. Mutations occur through radiation or other environmental influences.
• D. Mutations help adenine combine with guanine to form the single spiral structure of DNA.

Correct answer: C

Rationale: The correct answer is C. Mutations can occur due to environmental influences such as radiation, chemicals, or other external factors, leading to changes in the DNA sequence. Choice A is incorrect because mutations can also occur due to errors in DNA replication, not solely by chance. Choice B is incorrect as mutations affect the DNA sequence itself, not the production of specific cells. Choice D is incorrect because mutations involve changes in the DNA sequence and do not specifically involve the formation of the DNA structure.

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