Nursing Elites

1. Which property of a substance refers to its ability to undergo a chemical change and form new substances?

• A. Density
• B. Mass
• C. Reactivity
• D. Volume

Correct answer: C

Rationale: Reactivity is the property of a substance that describes its ability to undergo a chemical change and form new substances through chemical reactions. Density, mass, and volume are physical properties of a substance and do not directly relate to its ability to undergo chemical changes. Density is the mass of a substance per unit volume, mass is the amount of matter present, and volume is the amount of space occupied by the substance. Reactivity specifically deals with how likely a substance is to engage in chemical reactions. Therefore, the correct answer is C - Reactivity.

2. What is the name for the sac-shaped structures in which carbon dioxide and oxygen exchange takes place?

• A. Kidneys
• B. Medulla oblongata
• C. Alveoli
• D. Bronchioles

Correct answer: C

Rationale: The alveoli are the tiny sac-shaped structures in the lungs where gas exchange occurs. Oxygen from the air we breathe diffuses into the bloodstream through the alveoli, while carbon dioxide, a waste product produced by cells, is removed from the blood and exhaled out of the body through the alveoli. Choices A, B, and D are incorrect. Kidneys are organs responsible for filtering waste from the blood, the medulla oblongata is a part of the brain responsible for autonomic functions, and bronchioles are smaller airway passages in the lungs that branch off from the bronchi.

3. 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.

4. What is a rod-shaped structure that forms when a single DNA molecule and its associated proteins coil tightly before cell division?

• A. Centromere
• B. Chromatid
• C. Chromosome
• D. Gene

Correct answer: C

Rationale: A chromosome is a rod-shaped structure that forms when a single DNA molecule and its associated proteins coil tightly before cell division. It contains the genetic material and is essential for cell division and replication. The centromere is a specific region of a chromosome that plays a role in cell division. A chromatid is one half of a duplicated chromosome, and a gene is a unit of heredity responsible for specific traits. Therefore, the correct answer is 'Chromosome' as it represents the entire condensed DNA molecule during cell division.

5. Which of the following hormones is responsible for regulating blood sugar levels?

• A. Insulin
• B. Adrenaline
• C. Cortisol
• D. Melatonin

Correct answer: A

Rationale: Insulin is the hormone responsible for regulating blood sugar levels by facilitating the uptake of glucose into cells. Insulin helps lower blood sugar levels by promoting the storage of glucose in the liver, muscle, and fat cells. Adrenaline, cortisol, and melatonin do not directly regulate blood sugar levels. Adrenaline is involved in the fight-or-flight response, cortisol is a stress hormone that affects metabolism, immune response, and anti-inflammatory actions, while melatonin regulates sleep-wake cycles.

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