Nursing Elites

1. The number of protons in an atom determines its:

• A. Mass number
• B. Atomic number
• C. Atomic weight
• D. Valence electron count

Correct answer: B

Rationale: The number of protons in an atom is known as the atomic number. The atomic number uniquely identifies an element and determines its position on the periodic table. It is a fundamental property of an element and directly influences its chemical behavior and interactions. The mass number, on the other hand, is the sum of protons and neutrons in the nucleus of an atom, not just protons. Atomic weight is the average mass of an element's isotopes considering their relative abundance, not solely based on the number of protons. Valence electron count refers to the number of electrons in the outermost energy level of an atom, influencing its ability to form bonds and participate in chemical reactions, but it is not determined by the number of protons in the atom.

2. Which of the following is a common characteristic of alkynes?

• A. They have a triple bond between carbon atoms.
• B. They are saturated hydrocarbons.
• C. They contain only single bonds.
• D. They are aromatic compounds.

Correct answer: A

Rationale: The correct answer is A. Alkynes are hydrocarbons characterized by at least one triple bond between carbon atoms. This triple bond sets them apart from alkanes, which only have single bonds, and alkenes, which feature at least one double bond. The presence of a triple bond makes alkynes unsaturated hydrocarbons. Choice B is incorrect as alkynes are unsaturated hydrocarbons, not saturated. Choice C is incorrect because alkynes contain at least one triple bond, making them different from compounds with only single bonds. Choice D is incorrect because aromatic compounds have a distinct cyclic structure with resonance stabilization, a feature not shared by alkynes.

3. What is the primary mode of CO2 transport in the body?

• A. Bicarbonate
• B. Carbamino compounds
• C. None of these
• D. Plasma

Correct answer: A

Rationale: The correct answer is A: Bicarbonate. In the body, the primary mode of CO2 transport is as bicarbonate. Carbon dioxide is converted to bicarbonate in red blood cells as part of the bicarbonate buffer system, which helps maintain the pH balance in the blood. Bicarbonate is then transported in the plasma to the lungs where it is converted back to carbon dioxide for exhalation. While carbamino compounds also play a role in CO2 transport by binding to amino groups on proteins, bicarbonate is the main mode of transport for carbon dioxide in the body. Options B, C, and D are incorrect as they do not represent the primary mechanism of CO2 transport in the body.

4. Which of the following are the reproductive cells produced by meiosis?

• A. Genes
• B. Alleles
• C. Chromatids
• D. Gametes

Correct answer: D

Rationale: The correct answer is D. Gametes are the reproductive cells produced by meiosis. Meiosis is the cell division process that results in the formation of gametes, which are sperm cells in males and egg cells in females. Genes (A), alleles (B), and chromatids (C) are not the reproductive cells produced by meiosis. Genes are units of heredity, alleles are different forms of a gene, and chromatids are duplicated chromosomes involved in cell division.

5. The pancreas releases a number of digestive enzymes into the small intestine. Which of the following enzymes is NOT produced by the pancreas?

• A. Trypsin (protein digestion)
• B. Amylase (carbohydrate digestion)
• C. Lipase (fat digestion)
• D. Lactase (sugar digestion)

Correct answer: D

Rationale: Lactase is an enzyme responsible for breaking down lactose, a sugar found in dairy products, and it is produced by the small intestine, not the pancreas. The pancreas produces enzymes like trypsin for protein digestion, amylase for carbohydrate digestion, and lipase for fat digestion. Therefore, the correct answer is D. Choices A, B, and C are incorrect because trypsin, amylase, and lipase are indeed enzymes produced by the pancreas for the digestion of proteins, carbohydrates, and fats, respectively.

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