Nursing Elites

1. Antigen-antibody binding is the principle behind:

• A. Vaccination
• B. Disinfection
• C. Sterilization
• D. antibiotic resistance

Correct answer: A

Rationale: Rationale: Antigen-antibody binding is the principle behind vaccination. When a vaccine containing antigens (weakened or killed pathogens) is introduced into the body, the immune system produces antibodies that bind to these antigens. This binding triggers an immune response, leading to the production of memory cells that provide immunity against future infections by the same pathogen. Vaccination helps the body develop immunity without causing the disease itself, thereby protecting individuals from infectious diseases. Disinfection and sterilization involve different processes to eliminate or reduce pathogens on surfaces or objects. Antibiotic resistance is a phenomenon where bacteria evolve to resist the effects of antibiotics and is not directly related to antigen-antibody binding.

2. What is the significance of the nuclear envelope breaking down during mitosis?

• A. It allows the chromosomes to condense and become visible.
• B. It allows the spindle apparatus to form and attach to the chromosomes.
• C. It allows the sister chromatids to separate.
• D. It allows the nuclear material to be evenly distributed to the daughter cells.

Correct answer: B

Rationale: Rationale: A) The breakdown of the nuclear envelope does not directly cause the chromosomes to condense and become visible. Chromosome condensation is a separate process that occurs before mitosis begins. B) The breakdown of the nuclear envelope is crucial for the formation of the spindle apparatus, a structure made of microtubules that helps separate the chromosomes during cell division. The spindle apparatus attaches to the chromosomes and helps move them to opposite poles of the cell. C) The separation of sister chromatids occurs during anaphase, which is facilitated by the spindle apparatus. The breakdown of the nuclear envelope is not directly involved in this process. D) The even distribution of nuclear material to daughter cells is achieved through the movement of chromosomes by the spindle apparatus, which is made possible by the breakdown of the nuclear envelope.

3. Which of the following describes a scalar quantity?

• A. Velocity
• B. Acceleration
• C. Force
• D. Speed

Correct answer: d

Rationale: Speed is a scalar quantity as it only indicates how fast an object is moving without any directional information.

4. A temporary loss of consciousness due to insufficient blood flow to the brain is called:

• A. Stroke
• B. Seizure
• C. Syncope (fainting)
• D. Coma

Correct answer: C

Rationale: The correct answer is C: "Syncope (fainting)". Syncope is a temporary loss of consciousness caused by insufficient blood flow to the brain. During syncope, there is a brief interruption in the brain's blood supply, leading to a temporary loss of consciousness and muscle tone. This is different from a stroke (A), which is caused by a blockage or rupture of blood vessels in the brain, resulting in permanent damage. Seizures (B) involve abnormal electrical activity in the brain and can cause a variety of symptoms, including loss of consciousness, but they are not specifically due to insufficient blood flow. Coma (D) is a state of prolonged unconsciousness where a person is unresponsive and cannot be awakened. Therefore, the most appropriate term for a temporary loss of consciousness due to insufficient blood flow to the brain is syncope.

5. Sunscreen protects the skin from harmful ultraviolet (UV) rays by

• A. Reflecting UV rays away from the skin
• B. Absorbing UV rays and converting them to heat
• C. Blocking UV rays completely
• D. Stimulating melanin production

Correct answer: B

Rationale: The correct answer is B: Absorbing UV rays and converting them to heat. Sunscreen contains ingredients that act as filters to absorb UV radiation before it reaches the skin. These filters then convert the UV rays into a less harmful form of energy, usually heat, which is then released from the body. This process helps prevent UV radiation from damaging the skin cells and causing sunburn or long-term skin damage. Reflecting UV rays away from the skin (A) and blocking UV rays completely (C) are not accurate functions of sunscreen. Additionally, stimulating melanin production (D) is not a direct way in which sunscreen protects the skin from UV rays.

6. Colligative properties of solutions depend on the...

• A. Concentration of the solvent
• B. All of the 3 answers given
• C. Chemical identity of the solute
• D. Number of solute particles in solution

Correct answer: D

Rationale: The correct answer is D: 'Number of solute particles in solution.' Colligative properties, such as boiling point elevation and freezing point depression, depend on the number of solute particles present in a solution, not on the chemical identity of the solute or the concentration of the solvent. This is because the presence of solute particles disrupts the solvent's normal behavior, affecting these properties. Therefore, the number of solute particles in solution directly influences colligative properties, making it the most accurate choice among the options provided.

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