Nursing Elites

1. What type of chemical bond connects the oxygen and hydrogen atoms in a molecule of water?

• A. Static bond
• B. Aquatic bond
• C. Ionic bond
• D. Covalent bond

Correct answer: D

Rationale: The correct answer is D, Covalent bond. Covalent bonds are formed between oxygen and hydrogen atoms in a water molecule. In a water molecule, each hydrogen atom forms a covalent bond with the oxygen atom, sharing electrons to achieve a stable configuration. Static bond (choice A) and Aquatic bond (choice B) are not valid types of chemical bonds. Ionic bond (choice C) involves the transfer of electrons between atoms of different electronegativities, which is not the case between oxygen and hydrogen in a water molecule.

2. An uncharged atom has an electron configuration of 1s² 2s² 2p⁶ 3s² and a mass number of 14. How many protons does it have?

• A. 14
• B. 6
• C. 8
• D. 12

Correct answer: B

Rationale: The number of protons in an atom is determined by the atomic number, which is equal to the number of protons in the nucleus. The electron configuration given corresponds to carbon (C) with 6 protons. The atomic number of an element is the same as the number of protons in its nucleus, so in this case, the atom has 6 protons. Choices A, C, and D are incorrect because they do not correspond to the correct number of protons for an atom with the given electron configuration and mass number. Therefore, option B, 6 protons, is the correct answer.

3. Which concentration unit depends on pressure?

• A. ppm
• B. ppb
• C. molarity
• D. molarity, ppb, and ppm

Correct answer: C

Rationale: The correct answer is 'C: molarity.' Molarity is the concentration unit that depends on pressure. In molarity, the concentration of a solution is expressed as the number of moles of solute per liter of solution. This means that changes in pressure can affect the volume of the solution and consequently the concentration. Choices A and B, ppm (parts per million) and ppb (parts per billion), respectively, are independent of pressure variations as they are based on mass ratios. Therefore, molarity is the only concentration unit listed that is directly influenced by changes in pressure.

4. What is the main function of peroxisomes in the cell?

• A. To break down hydrogen peroxide
• B. To synthesize lipids and other cellular components
• C. To package and transport proteins
• D. To store genetic material

Correct answer: A

Rationale: Peroxisomes are membrane-bound organelles found in eukaryotic cells that contain enzymes involved in various metabolic processes. One of the main functions of peroxisomes is to break down hydrogen peroxide, a toxic byproduct of metabolism, into water and oxygen through the action of the enzyme catalase. This process helps protect the cell from oxidative damage caused by hydrogen peroxide. While peroxisomes are involved in other metabolic functions such as lipid metabolism and the synthesis of bile acids, their primary role is the breakdown of hydrogen peroxide. Choices B, C, and D are incorrect because peroxisomes are not primarily responsible for synthesizing lipids, packaging and transporting proteins, or storing genetic material within the cell.

5. Which of the following types of stem cells can differentiate into any cell type, including forming an entire organism?

• A. Totipotent stem cells
• B. Multipotent stem cells
• C. Pluripotent stem cells
• D. Hematopoietic stem cells

Correct answer: A

Rationale: Totipotent stem cells possess the unique ability to differentiate into any cell type, including forming an entire organism. These cells have the highest potency level and can give rise to both embryonic and extraembryonic cell types, allowing them to develop into a complete organism. Multipotent stem cells (Choice B) can differentiate into a limited range of cell types within a specific tissue or organ. Pluripotent stem cells (Choice C) can differentiate into any cell type in the body except for those needed to support and develop a fetus. Hematopoietic stem cells (Choice D) are a type of multipotent stem cell that can differentiate into various blood cell types.

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