Nursing Elites

1. What are the three types of muscle tissues?

• A. Cardiac, smooth, epithelial
• B. Skeletal, cardiac, smooth
• C. Cardiac, smooth, connective
• D. Skeletal, epithelial, connective

Correct answer: B

Rationale: The correct answer is B: Skeletal, cardiac, smooth. Skeletal muscle tissue is responsible for voluntary movement, cardiac muscle tissue is found in the heart and is responsible for involuntary heart contractions, and smooth muscle tissue is located in organs and is responsible for involuntary movements. Therefore, the three types of muscle tissues are skeletal, cardiac, and smooth. Choices A, C, and D are incorrect because they include types of tissues that are not classified as muscle tissues. Epithelial and connective tissues are different types of tissues that serve other functions in the body, not related to muscle contractions.

2. What is a gene, and what is the relationship between genes, genotype, and phenotype?

• A. A gene is a sequence of amino acids; genes make up proteins; genotype determines phenotype
• B. A gene is a portion of DNA; genes determine traits; genotype is the genetic makeup; phenotype is the physical manifestation
• C. A gene is a protein; proteins determine traits; genotype is the set of all genes
• D. A gene is a lipid; lipids determine traits; phenotype is the physical manifestation

Correct answer: B

Rationale: A gene is a portion of DNA that contains the instructions for a specific trait. Genotype refers to the genetic makeup of an organism, encompassing all its genes. Phenotype, on the other hand, is the observable physical manifestation resulting from the interaction between an organism's genotype and environmental factors. Choice A is incorrect because genes do not consist of amino acids directly; they are sequences of nucleotides. Choice C is incorrect as genes do not determine traits directly but provide the instructions for proteins that may influence traits. Choice D is incorrect as genes are not lipids, and lipids do not determine traits; they are a type of biomolecule with different functions.

3. Which of the following organs is responsible for churning and mechanically breaking down food?

• A. Small intestine
• B. Large intestine
• C. Stomach
• D. Esophagus

Correct answer: C

Rationale: The correct answer is C, the stomach. The stomach is responsible for churning and mechanically breaking down food. It contains muscles that contract and relax to mix food with digestive juices, breaking it down into smaller particles. This mechanical digestion process helps prepare the food for further digestion and absorption in the small intestine. The small intestine is primarily responsible for the absorption of nutrients, not for mechanical digestion. The large intestine absorbs water and salts, and the esophagus is a muscular tube that transports food from the mouth to the stomach, not involved in churning or breaking down food.

4. Which of the following structures in the respiratory system is responsible for gas exchange?

• A. Trachea
• B. Alveoli
• C. Bronchi
• D. Diaphragm

Correct answer: B

Rationale: The correct answer is B: Alveoli. The alveoli in the lungs are responsible for gas exchange. They have a thin membrane that allows for the exchange of oxygen and carbon dioxide between the air in the lungs and the blood in the capillaries surrounding them. This process is essential for respiration, providing oxygen to the body's tissues and removing carbon dioxide, a waste product of cellular metabolism. Choices A, C, and D are incorrect. The trachea is a passageway that carries air to and from the lungs but is not directly involved in gas exchange. Bronchi are airway passages that further divide into smaller bronchioles leading to the alveoli but do not perform gas exchange themselves. The diaphragm is a muscle involved in the breathing process by aiding in inhalation and exhalation, but it is not the structure responsible for gas exchange in the respiratory system.

5. Which of the following is a constant?

• A. The number of protons in an oxygen atom
• B. The temperature at which iron ore will melt
• C. The human population size
• D. The time the sun rises each day

Correct answer: A

Rationale: The number of protons in an oxygen atom is a constant. This value is determined by the atomic number of the element and does not change regardless of the isotope of oxygen. The number of protons defines the element and remains consistent under normal conditions. Choices B, C, and D are not constants. The temperature at which iron ore will melt can vary depending on factors like pressure, the human population size is constantly changing, and the time the sun rises each day varies with the seasons and location.

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