Nursing Elites

1. Which of the following statements about prions is TRUE?

• A. They are composed of proteins only
• B. They are easily destroyed by common disinfectants
• C. hey are a type of antibiotic
• D. They are a live organism

Correct answer: A

Rationale: Rationale: A) This statement is true. Prions are infectious agents composed entirely of protein, lacking nucleic acids such as DNA or RNA. They are known for causing neurodegenerative diseases in animals and humans. B) This statement is false. Prions are not easily destroyed by common disinfectants due to their unique structure and resistance to conventional sterilization methods. C) This statement is false. Prions are not a type of antibiotic. They are a distinct class of infectious agents. D) This statement is false. Prions are not live organisms but rather misfolded proteins that can induce abnormal folding in normal proteins, leading to disease.

2. What is the process by which bacteria can acquire new genetic material from their environment?

• A. Transformation
• B. Transduction
• C. Conjugation
• D. All of the above

Correct answer: D

Rationale: Rationale: A) Transformation: Transformation is the process by which bacteria can take up free DNA from their environment and incorporate it into their own genome. This can lead to the acquisition of new genetic material and traits. B) Transduction: Transduction is a process where genetic material is transferred from one bacterium to another by a bacteriophage (a virus that infects bacteria). During transduction, the bacteriophage carries bacterial DNA from one host cell to another, allowing for the transfer of genetic material. C) Conjugation: Conjugation is a mechanism of horizontal gene transfer in bacteria where genetic material is transferred between two bacterial cells that are in direct contact. This transfer is mediated by a conjugative plasmid that carries the genetic information to be transferred. Therefore, all of the processes mentioned (transformation, transduction, and conjugation) are ways in which bacteria can acquire new genetic material from their environment.

3. The diaphragm is a dome-shaped muscle that plays a crucial role in breathing. When it contracts, what happens?

• A. Air is expelled from the lungs.
• B. The lungs expand to allow air intake.
• C. The vocal cords vibrate to produce sound.
• D. The trachea narrows to control airflow.

Correct answer: B

Rationale: The diaphragm is a dome-shaped muscle located beneath the lungs. When it contracts, it moves downward, creating more space in the chest cavity. This downward movement of the diaphragm allows the lungs to expand, which lowers the air pressure inside the lungs. As a result, air from the outside rushes in to equalize the pressure, leading to inhalation. Therefore, when the diaphragm contracts, it facilitates the intake of air into the lungs, making option B, 'The lungs expand to allow air intake,' the correct answer.

4. Which structure in the respiratory system serves as a passageway for both air and food, with a flap-like structure that prevents food from entering the trachea during swallowing?

• A. Larynx
• B. Pharynx
• C. Trachea
• D. Bronchi

Correct answer: B

Rationale: The correct answer is B: Pharynx. The pharynx is a structure in the respiratory system that serves as a passageway for both air and food. It has a flap-like structure called the epiglottis, which prevents food from entering the trachea during swallowing. The larynx is commonly known as the voice box and is responsible for sound production. The trachea is a tube that carries air to and from the lungs, and the bronchi are the two main branches that lead from the trachea to the lungs. Therefore, the pharynx is the correct answer as it specifically fits the description provided in the question.

5. When unpolarized light passes through a polarizing filter, the intensity of the transmitted light is:

• A. Completely absorbed
• B. Reduced by half
• C. Unaffected
• D. Doubled

Correct answer: B

Rationale: When unpolarized light passes through a polarizing filter, the intensity of the transmitted light is reduced by half. This is because a polarizing filter only allows light waves oscillating in one plane to pass through while blocking the other perpendicular plane. Unpolarized light consists of waves oscillating in all possible planes, so when it passes through the polarizer, only half of the light waves aligned with the filter's polarization direction can transmit through. As a result, the intensity of the transmitted light is reduced by half as only a portion of the original light waves can pass through the filter.

6. A light ray travels from air (refractive index 1.00) into water (refractive index 1.33). What happens to its speed and direction?

• A. Speed increases, direction bends towards the normal.
• B. Speed increases, direction bends away from the normal.
• C. Speed decreases, direction bends towards the normal.
• D. Speed and direction remain unchanged.

Correct answer: A

Rationale: Due to the change in refractive index, the light ray bends towards the normal (water) as it slows down upon entering the denser medium.

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