Nursing Elites

1. What is the primary difference between ionic and metallic bonding?

• A. Ionic bonds involve electron transfer, while metallic bonds involve electron sharing.
• B. Ionic bonds are weak and directional, while metallic bonds are strong and non-directional.
• C. Ionic bonds exist between metals and non-metals, while metallic bonds exist only between metals.
• D. Ionic bonds form discrete molecules, while metallic bonds form extended structures.

Correct answer: B

Rationale: Ionic bonds involve electron transfer, where one atom completely donates an electron to another, resulting in discrete molecules. On the other hand, metallic bonds are non-directional and strong, formed by a 'sea' of delocalized electrons shared among all metal atoms. This shared electron cloud allows for strong bonding throughout the entire material, making metallic bonds non-directional and strong compared to the directional and weaker nature of ionic bonds. Choice A is incorrect because metallic bonds do not involve electron sharing but rather the sharing of a sea of delocalized electrons. Choice C is incorrect as metallic bonds can also exist between metal atoms, not just between metals and non-metals. Choice D is incorrect because metallic bonds do not form discrete molecules but rather extended structures due to the sharing of electrons among all metal atoms.

2. What is the role of RNA interference in silencing genes?

• A. Increases protein production
• B. Promotes gene mutation
• C. Inhibits the expression of specific genes
• D. Repairs damaged DNA

Correct answer: C

Rationale: RNA interference (RNAi) is a biological process that involves the silencing of gene expression by inhibiting the translation of mRNA or by degrading mRNA molecules. This mechanism plays a crucial role in regulating gene expression and can be used to selectively silence specific genes. By interfering with the expression of specific genes, RNAi can downregulate protein production from those genes. Therefore, option C, 'Inhibits the expression of specific genes,' is the correct role of RNA interference in silencing genes. Options A, B, and D are incorrect because RNA interference does not increase protein production, promote gene mutation, or repair damaged DNA; its primary function is to inhibit gene expression by degrading or interfering with mRNA.

3. Which of the following is a balanced chemical equation?

• A. H2 + O2 → H2O
• B. 2H2 + O2 → 2H2O
• C. 3H2O → 2H2 + O2
• D. H2O → H2 + O2

Correct answer: B

Rationale: A balanced chemical equation must have the same number of atoms of each element on both sides of the equation. In option B, 2H2 + O2 → 2H2O, the equation is balanced as there are 2 hydrogen atoms and 2 oxygen atoms on both the reactant and product sides after balancing, satisfying the law of conservation of mass. Option A is unbalanced as there are 2 oxygen atoms on the reactant side but only 1 oxygen atom on the product side. Option C is unbalanced with 3 hydrogen atoms on the reactant side and 2 hydrogen atoms on the product side. Option D is unbalanced with 1 oxygen atom on the reactant side and 2 oxygen atoms on the product side.

4. Where is pseudostratified columnar epithelium primarily found?

• A. Skeletal muscle
• B. Bony skeleton
• C. External ears
• D. Bloodstream

Correct answer: C

Rationale: Pseudostratified columnar epithelium is a type of epithelial tissue found in the respiratory tract, including the lining of the trachea and bronchi. It is also found in the male reproductive system and parts of the auditory tube and external ear canal. Among the options provided, the external ears (option C) are the most relevant location for pseudostratified columnar epithelium. Skeletal muscle (option A) is primarily composed of muscle fibers, not epithelial tissue. The bony skeleton (option B) is composed of bone tissue. The bloodstream (option D) consists of blood cells and plasma, not epithelial tissue.

5. What is the muscular sac in the female body that nourishes and protects a developing fetus?

• A. Ovary
• B. Fallopian tube
• C. Uterus
• D. Vagina

Correct answer: C

Rationale: The correct answer is the uterus. The uterus is a muscular organ in the female body where a fertilized egg implants and grows into a fetus during pregnancy. It provides nourishment and protection to the developing fetus. The ovaries produce eggs, the fallopian tubes transport eggs from the ovaries to the uterus, and the vagina is the muscular tube that connects the uterus to the outside of the body for childbirth. Therefore, the roles of the ovary, fallopian tube, and vagina are not related to nourishing and protecting a developing fetus, making them incorrect choices.

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