Nursing Elites

1. Which of the following is a type of white blood cell that plays a key role in adaptive immunity by seeking out, attacking, and destroying targeted pathogens?

• A. memory B cells
• B. neutrophils
• C. antibodies
• D. cytotoxic T cells

Correct answer: D

Rationale: The correct answer is cytotoxic T cells. Cytotoxic T cells are a type of white blood cell that is crucial in adaptive immunity. They are specialized in recognizing and destroying infected or abnormal cells in the body. Neutrophils are primarily involved in innate immunity, providing rapid response to infections. Antibodies are proteins produced by B cells and are essential in specific immune responses, but they do not directly attack pathogens. Memory B cells are part of the adaptive immune response, responsible for mounting a quicker and stronger response upon re-exposure to a pathogen. However, they do not directly seek out and destroy pathogens like cytotoxic T cells do.

2. Are red hair and a height of six feet part of an individual's genotype or phenotype?

• A. Red hair is part of the phenotype; height is part of the genotype.
• B. Red hair is part of the genotype; height is part of the phenotype.
• C. Both characteristics describe his genotype.
• D. Both characteristics describe his phenotype.

Correct answer: D

Rationale: In the context of genetics, genotype refers to an individual's genetic makeup, while phenotype refers to the observable characteristics resulting from the interaction of the genotype with the environment. Red hair and a height of six feet are observable characteristics, making them part of the individual's phenotype. Therefore, both red hair and height are aspects of the individual's phenotype. Choices A and B are incorrect as they incorrectly assign one characteristic to the genotype and the other to the phenotype, which is not accurate. Choice C is incorrect as it states that both characteristics describe the genotype, which is inaccurate as they are observable traits. The correct answer is D, as both red hair and height are observable traits or characteristics, falling under the definition of phenotype in genetics.

3. DNA has both a 'sense' and 'antisense' strand. What is true about the antisense strand?

• A. It runs 5' to 3'.
• B. It runs 3' to 5'.
• C. It is used in replication.
• D. It is the direction DNA is stored.

Correct answer: B

Rationale: The correct answer is B: 'It runs 3' to 5'. The antisense strand runs in the 3' to 5' direction, complementing the sense strand. Choice A is incorrect as the antisense strand runs in the opposite direction, which is 3' to 5'. Choice C is incorrect because the antisense strand is not directly involved in replication. Choice D is incorrect as the direction DNA is stored is not determined by the antisense strand.

4. Which type of cell is responsible for carrying oxygen throughout the body?

• A. Nerve cell
• B. Muscle cell
• C. Skin cell
• D. Red blood cell

Correct answer: D

Rationale: The correct answer is D: Red blood cell. Red blood cells, also known as erythrocytes, are specifically designed to carry oxygen throughout the body. They contain hemoglobin, a protein that binds to oxygen in the lungs and transports it to tissues and organs in the body. Nerve cells, muscle cells, and skin cells do not have the specialized function of carrying oxygen like red blood cells do. Nerve cells transmit electrical signals, muscle cells are involved in movement, and skin cells provide a protective barrier and regulate body temperature. Therefore, choices A, B, and C are incorrect in the context of carrying oxygen throughout the body.

5. Which valve prevents the return of blood into the right ventricle?

• A. Pulmonary semilunar valve
• B. Aortic semilunar valve
• C. Tricuspid valve
• D. Mitral valve

Correct answer: A

Rationale: The correct answer is A: Pulmonary semilunar valve. The pulmonary semilunar valve is located between the right ventricle and the pulmonary artery. It opens to allow blood to be pumped into the pulmonary artery but closes to prevent blood from returning back into the right ventricle. The aortic semilunar valve is located between the left ventricle and the aorta. The tricuspid valve is located between the right atrium and right ventricle, and the mitral valve is located between the left atrium and left ventricle. Therefore, the pulmonary semilunar valve is the specific valve responsible for preventing the backflow of blood into the right ventricle during the cardiac cycle.

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