Nursing Elites

1. How many mL of a 0 M stock solution of HCl should be added to water to create 250 mL of a 50 M solution of HCl?

• A. 31.25 mL
• B. 32 mL
• C. 30 mL
• D. 31.3 mL

Correct answer: B

Rationale: To prepare 250 mL of a 50 M solution of HCl, the formula V1 x C1 = V2 x C2 is used, where V1 is the volume of the stock solution, C1 is the concentration of the stock solution, V2 is the final volume of the desired solution, and C2 is the final concentration of the desired solution. Given V1 x 0 M = 250 mL x 50 M, solving for V1 results in V1 = (250 mL x 50 M) / 0 M = 32 mL. Therefore, 32 mL of the 0 M stock solution of HCl needs to be added to water to create a 250 mL solution of 50 M HCl. Choices A, C, and D are incorrect because they do not represent the accurate volume required for the dilution calculation based on the given concentrations and volumes in the problem.

2. Which enzyme found in saliva is responsible for breaking down carbohydrates into smaller molecules like sugars?

• A. Pepsin
• B. Amylase
• C. Lipase
• D. Trypsin

Correct answer: B

Rationale: The correct answer is B. Saliva contains an enzyme called amylase, which specifically targets carbohydrates and breaks them down into smaller molecules like sugars. Pepsin, choice A, is an enzyme found in the stomach that breaks down proteins, not carbohydrates. Lipase, choice C, is responsible for breaking down fats, not carbohydrates. Trypsin, choice D, is an enzyme that breaks down proteins in the small intestine, not carbohydrates. Therefore, choices A, C, and D are incorrect for this question.

3. What is the cycle of infection?

• A. Reservoir host, means of exit, means of transmission, means of entrance, susceptible host
• B. Entry point, transmission, replication, exit, susceptible host
• C. Susceptible host, replication, transmission, entry, exit
• D. Transmission, replication, entry, exit, susceptible host

Correct answer: A

Rationale: The correct answer is A: 'Reservoir host, means of exit, means of transmission, means of entrance, susceptible host.' This cycle of infection involves the pathogen starting in a reservoir host, exiting through a means, being transmitted to another host, entering the new host through a means, and ultimately infecting the susceptible host. Choices B, C, and D are incorrect because they do not follow the correct sequence of events in the cycle of infection.

4. Which of the following lobes of the brain is primarily responsible for vision?

• A. Frontal
• B. Occipital
• C. Parietal
• D. Temporal

Correct answer: B

Rationale: The occipital lobe is primarily responsible for processing visual information. It contains the primary visual cortex, which plays a key role in interpreting visual stimuli. The frontal lobe is more associated with functions such as decision-making and problem-solving, making choice A incorrect. The parietal lobe is involved in processing sensory information but not specifically vision, making choice C incorrect. The temporal lobe is responsible for functions like memory and auditory processing, so choice D is also incorrect.

5. What is the term for the small air sacs in the lungs where gas exchange (oxygen and carbon dioxide) takes place?

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

Correct answer: B

Rationale: The correct answer is B: Alveoli. The alveoli are the small air sacs in the lungs where gas exchange occurs. Oxygen from the air we breathe passes into the bloodstream through the alveoli, while carbon dioxide from the bloodstream passes out of the body through the alveoli. Choice A, Bronchi, are the main airways in the lungs and not the site of gas exchange. Choice C, Trachea, refers to the windpipe, which is a different structure than the alveoli. Choice D, Bronchioles, are smaller airways branching off from the bronchi and are not where gas exchange primarily occurs.

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