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.
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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.
Which FHR finding is the most concerning to the nurse providing care to a laboring client?
- A. Accelerations with fetal movement.
- B. Early decelerations.
- C. Average FHR of 126 beats per minute.
- D. Late decelerations.
Correct Answer: D
Rationale: Late decelerations are caused by uteroplacental insufficiency, resulting in fetal hypoxemia. They are considered ominous if persistent, indicating compromised oxygen supply to the fetus. Accelerations with fetal movement (Choice A) are reassuring signs of fetal well-being. Early decelerations (Choice B) are typically benign, associated with head compression during contractions. An average FHR of 126 beats per minute (Choice C) falls within the normal range for fetal heart rate and is not concerning. Therefore, the most concerning FHR finding in a laboring client is late decelerations (Choice D).
What is the structure of deoxyribonucleic acid (DNA)?
- A. single spiral
- B. double helix
- C. sphere
- D. cube
Correct Answer: B
Rationale: The correct answer is B: double helix. DNA is structured as a double helix, resembling a twisted ladder made up of two strands of nucleotides. Choice A, single spiral, is incorrect as DNA is not a single spiral structure. Choice C, sphere, is incorrect as DNA does not form a spherical shape. Choice D, cube, is incorrect as DNA does not have a cubic structure. Understanding the double helix structure of DNA is essential as it allows for the storage and transmission of genetic information in living organisms.
A nurse is reviewing laboratory results for a term newborn who is 24 hours old. Which of the following results require intervention by the nurse?
- A. WBC count 10,000/mm3
- B. Platelets 180,000/mm3
- C. Hemoglobin 20g/dL
- D. Glucose 20 mg/dL
Correct Answer: D
Rationale: A glucose level of 20 mg/dL is critically low for a newborn and requires immediate intervention. Hypoglycemia in a newborn can lead to serious complications such as neurologic deficits. The normal range for glucose levels in a newborn is typically 40-60 mg/dL. Choices A, B, and C represent normal or acceptable values for a term newborn and do not require immediate intervention. A WBC count of 10,000/mm3, platelets of 180,000/mm3, and hemoglobin of 20g/dL are all within normal ranges for a term newborn and do not raise immediate concerns.
Which of the following is a sexually transmitted infection that, in advanced stages, can attack major organ systems?
- A. Rubella
- B. Syphilis
- C. Cystic fibrosis
- D. Phenylketonuria
Correct Answer: B
Rationale: Syphilis is the correct answer. Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum. If left untreated, it can progress through various stages and potentially attack major organ systems, causing severe complications. Rubella, Cystic fibrosis, and Phenylketonuria are not sexually transmitted infections. Rubella is a viral infection, Cystic fibrosis is a genetic disorder affecting the lungs and digestive system, and Phenylketonuria is a genetic metabolic disorder. These conditions do not typically affect major organ systems in the same way as untreated syphilis.