Nokea
What is the most common cause of hospital-acquired infections (HAIs)?
- A. Viruses
- B. Bacteria
- C. Fungi
- D. Parasites
Correct Answer: B
Rationale: Hospital-acquired infections (HAIs), also known as nosocomial infections, are infections that patients acquire during the course of receiving treatment in a healthcare facility. Among the options provided, bacteria are the most common cause of HAIs. Bacteria such as Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa are known to cause a wide range of infections in healthcare settings. While viruses, fungi, and parasites can also cause HAIs, bacteria are the most prevalent and significant pathogens responsible for these infections. Proper infection control measures, including hand hygiene, environmental cleaning, and antimicrobial stewardship, are essential in preventing and controlling HAIs caused by bacteria.
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Which respiratory structure is responsible for the production of mucus to trap particles and for the movement of cilia to sweep mucus and trapped particles out of the respiratory tract?
- A. Trachea
- B. Larynx
- C. Bronchi
- D. Respiratory epithelium
Correct Answer: D
Rationale: The respiratory epithelium is the correct answer because it is the tissue lining the respiratory tract responsible for producing mucus to trap particles and containing cilia that sweep the mucus and trapped particles out of the respiratory tract. The trachea, larynx, and bronchi are all structures within the respiratory system but do not specifically carry out the functions described in the question. The trachea is a passage for air, the larynx is involved in sound production and protecting the airway, and the bronchi are airway passages that branch from the trachea to the lungs. Only the respiratory epithelium fits the description of producing mucus and utilizing cilia for particle removal in the respiratory tract.
Balance the chemical equation: C4H10 + O2 → CO2 + H2O. What is the coefficient for oxygen?
- A. 5
- B. 6
- C. 7
- D. 8
Correct Answer: B
Rationale: To balance the chemical equation, we need to ensure that the number of each type of atom is the same on both sides of the equation. In this case, there are 10 oxygen atoms on the right side (5 in CO2 and 5 in H2O). To balance this, we need to add a coefficient of 6 in front of O2 on the left side, resulting in 6 O2 molecules. This change will give us a total of 12 oxygen atoms on both sides, making the equation balanced. Choice A (5) is incorrect because it does not account for all the oxygen atoms present in the products. Choices C (7) and D (8) are incorrect as they would result in an imbalance in the number of oxygen atoms on both sides of the equation.
What is the function of ribosomes?
- A. Packaging and transporting proteins
- B. Storing genetic material
- C. Controlling cell division
- D. Synthesizing proteins
Correct Answer: D
Rationale: The correct answer is D: Synthesizing proteins. Ribosomes are cellular organelles responsible for protein synthesis. They read the messenger RNA (mRNA) and utilize the information to assemble amino acids into proteins through a process known as translation. Choice A, packaging and transporting proteins, is incorrect as this function is typically performed by the Golgi apparatus and vesicles. Choice B, storing genetic material, is incorrect as genetic material is usually stored in the nucleus in the form of DNA. Choice C, controlling cell division, is incorrect as this function is primarily regulated by the cell cycle checkpoints and specific proteins involved in cell cycle regulation.
Neurons, the functional units of the nervous system, belong to which tissue type?
- A. Epithelial tissue
- B. Connective tissue
- C. Muscle tissue
- D. Nervous tissue
Correct Answer: D
Rationale: Neurons are the functional units of the nervous system and are specialized cells that transmit nerve impulses. They belong to nervous tissue, which is the primary tissue type of the nervous system. Nervous tissue is composed of neurons and supporting cells called neuroglia. Choices A, B, and C are incorrect because epithelial tissue functions mainly in covering and lining body surfaces, connective tissue provides support and structure, and muscle tissue is responsible for movement. Neurons, being the basic functional units of the nervous system, are specifically classified under nervous tissue.
Which type of glial cell provides structural support and insulation for neurons in the central nervous system?
- A. Schwann cells
- B. Astrocytes
- C. Oligodendrocytes
- D. Microglia
Correct Answer: C
Rationale: Oligodendrocytes are a type of glial cell that provides structural support and insulation for neurons in the central nervous system by forming myelin sheaths around axons. Schwann cells (option A) perform a similar function but in the peripheral nervous system. Astrocytes (option B) are involved in providing nutrients to neurons, maintaining the chemical environment, and repairing damage. Microglia (option D) are primarily responsible for immune defense in the central nervous system, not for providing structural support and insulation for neurons.