Nursing Elites

1. Which of the following nucleobases does not exist in RNA?

• A. Uracil
• B. Thymine
• C. Cytosine
• D. Guanine

Correct answer: B

Rationale: The correct answer is 'B: Thymine'. Thymine is a nucleobase found in DNA but is replaced by uracil in RNA. RNA contains Uracil, Cytosine, and Guanine as its nucleobases. Cytosine and Guanine are present in both DNA and RNA, while Thymine is exclusive to DNA and Uracil is specific to RNA.

2. Which of the following best describes eosinophils?

• A. A type of granulocyte that secretes histamine to stimulate the inflammatory response.
• B. The most abundant type of white blood cell that secretes substances toxic to pathogens.
• C. A type of granulocyte found under mucous membranes that defends against multicellular parasites.
• D. A circulating granulocyte with high phagocytic activity and aggressiveness.

Correct answer: C

Rationale: Eosinophils are best described as a type of granulocyte found under mucous membranes that defends against multicellular parasites. They release toxic substances to combat parasitic infections and play a significant role in allergic reactions and asthma. Histamine secretion to stimulate inflammation is more characteristic of basophils, while high phagocytic activity and aggressiveness are features of neutrophils, not eosinophils. Describing eosinophils as the most abundant type of white blood cell that secretes toxic substances to pathogens is inaccurate since eosinophils specifically target multicellular parasites, not a broad range of pathogens.

3. Which element has the lowest electronegativity value?

• A. Oxygen
• B. Fluorine
• C. Helium
• D. Chlorine

Correct answer: C

Rationale: The correct answer is Helium (C). Electronegativity is the tendency of an atom to attract electrons towards itself in a bond. Helium, as a noble gas, has a very low electronegativity because its outer electron shell is already full and stable, resulting in minimal attraction for additional electrons. Oxygen (A), Fluorine (B), and Chlorine (D) are all non-noble gas elements that have higher electronegativity values compared to Helium due to their electron configurations and tendencies to attract electrons.

4. Where does fertilization typically occur in the female reproductive system?

• A. uterus
• B. fallopian tube
• C. endometrium
• D. ovary

Correct answer: B

Rationale: Fertilization typically occurs in the fallopian tube, specifically in the ampulla, which is the widest part of the tube. After ovulation, the released egg travels through the fallopian tube where it may encounter sperm for fertilization to take place. The fallopian tube provides the ideal environment for fertilization due to the presence of cilia that help move the egg and sperm towards each other. The uterus is where the fertilized egg will implant and develop into a fetus, not where fertilization occurs. The endometrium is the lining of the uterus that thickens to support a potential pregnancy but is not the site of fertilization. The ovary releases the egg during ovulation but is not where fertilization occurs.

5. Balance the chemical equation: C4H10 + O2 → CO2 + H2O. What is the coefficient for oxygen?

• A. 5
• B. 6
• C. 7
• D. 8

Correct answer: B

Rationale: To balance the chemical equation, we need to ensure that the number of each type of atom is the same on both sides of the equation. In this case, there are 10 oxygen atoms on the right side (5 in CO2 and 5 in H2O). To balance this, we need to add a coefficient of 6 in front of O2 on the left side, resulting in 6 O2 molecules. This change will give us a total of 12 oxygen atoms on both sides, making the equation balanced. Choice A (5) is incorrect because it does not account for all the oxygen atoms present in the products. Choices C (7) and D (8) are incorrect as they would result in an imbalance in the number of oxygen atoms on both sides of the equation.

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