which of the following statements is true of mutations

HESI LPN

HESI Maternal Newborn

1. 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.

2. A woman gave birth to a 7-pound, 6-ounce infant girl 1 hour ago. The birth was vaginal and the estimated blood loss (EBL) was 1500 ml. When evaluating the woman’s vital signs, which finding would be of greatest concern to the nurse?

A. Temperature 37.9°C, heart rate 120 beats per minute (bpm), respirations 20 breaths per minute, and blood pressure 90/50 mm Hg.
B. Temperature 37.4°C, heart rate 88 bpm, respirations 36 breaths per minute, and blood pressure 126/68 mm Hg.
C. Temperature 38°C, heart rate 80 bpm, respirations 16 breaths per minute, and blood pressure 110/80 mm Hg.
D. Temperature 36.8°C, heart rate 60 bpm, respirations 18 breaths per minute, and blood pressure 140/90 mm Hg.

Correct answer: A

Rationale: An estimated blood loss (EBL) of 1500 ml following a vaginal birth is significant and can lead to hypovolemia. The vital signs provided in option A (Temperature 37.9°C, heart rate 120 bpm, respirations 20 breaths per minute, and blood pressure 90/50 mm Hg) indicate tachycardia and hypotension, which are concerning signs of hypovolemia due to excessive blood loss. Tachycardia is the body's compensatory mechanism to maintain cardiac output in response to decreased blood volume, and hypotension indicates inadequate perfusion. Options B, C, and D do not exhibit the same level of concern for hypovolemia. Option B shows tachypnea, which can be a result of pain or anxiety postpartum. Option C and D have vital signs within normal limits, which are not indicative of the body's response to significant blood loss.

3. A primiparous woman presents in labor with the following labs: hemoglobin 10.9 g/dL, hematocrit 29%, hepatitis surface antigen positive, Group B Streptococcus positive, and rubella non-immune. Which intervention should the nurse implement?

A. Transfuse 2 units of packed red blood cells.
B. Give measles, mumps, rubella vaccine 0.5 mL.
C. Administer ampicillin 2 grams intravenously.
D. Inject hepatitis B immune globulin 0.5 milliliters.

Correct answer: C

Rationale: The correct intervention in this scenario is to administer ampicillin 2 grams intravenously. This is crucial to prevent Group B Streptococcus infection in the newborn during delivery. Option A, transfusing packed red blood cells, is not indicated based on the hemoglobin and hematocrit levels provided. Option B, giving measles, mumps, rubella vaccine, is not necessary at this time. Option D, injecting hepatitis B immune globulin, is not appropriate for the conditions presented in the question.

4. A newborn is 24 hours old, and a healthcare provider is caring for them. Which of the following laboratory findings should the healthcare provider report to the provider?

A. Hgb 20 g/dL
B. Bilirubin 2 mg/dL
C. Platelets 200,000/mm3
D. WBC count 32,000/mm3

Correct answer: D

Rationale: The correct answer is D: WBC count 32,000/mm3. A WBC count of 32,000/mm3 is significantly elevated in a newborn and could indicate an infection, which needs immediate attention and intervention. High white blood cell counts in newborns can be concerning as they may suggest an ongoing infection or other underlying issues that require prompt medical evaluation and treatment. Choices A, B, and C are within normal ranges for a newborn and would not typically warrant immediate reporting to the provider. Hgb levels of 20 g/dL (Choice A) are high for newborns, but this is not as concerning as a significantly elevated WBC count. Bilirubin levels of 2 mg/dL (Choice B) are within normal limits for a newborn and do not indicate immediate issues. Platelet count of 200,000/mm3 (Choice C) is also within the normal range for a newborn and would not require immediate reporting.

5. Dizygotic (DZ) twins share _________ percent of their genes.

A. 100
B. 75
C. 50
D. 25

Correct answer: C

Rationale: Dizygotic (DZ) twins share approximately 50% of their genes. This is because dizygotic twins, also known as fraternal twins, originate from two separate fertilized eggs and share similar genetic similarity to regular siblings. Choice A (100%) is incorrect because if twins shared 100% of their genes, they would be identical twins (monozygotic). Choice B (75%) is incorrect as it is not the typical genetic similarity seen in dizygotic twins. Choice D (25%) is incorrect as it represents a significantly lower genetic similarity than what is observed in dizygotic twins.