Nursing Elites

1. Which transport mechanism uses vesicles to move materials out of the cell?

• A. Endocytosis
• B. Active transport
• C. Diffusion
• D. Exocytosis

Correct answer: D

Rationale: Exocytosis is the transport mechanism that uses vesicles to move materials out of the cell. Vesicles carry substances to the cell membrane, fuse with it, and release their contents outside the cell. This process is essential for secreting molecules such as hormones, enzymes, or neurotransmitters. Endocytosis, on the other hand, is the process of bringing materials into the cell by engulfing them in vesicles. Active transport involves the movement of molecules across a cell membrane against their concentration gradient, requiring energy. Diffusion is the passive movement of molecules from an area of higher concentration to an area of lower concentration.

2. Which of the following structures in the cell is responsible for producing ATP?

• A. Ribosome
• B. Nucleus
• C. Mitochondria
• D. Endoplasmic reticulum

Correct answer: C

Rationale: The correct answer is C, Mitochondria. Mitochondria are known as the powerhouse of the cell and are responsible for producing ATP, the primary energy currency of the cell through cellular respiration. Ribosomes (Choice A) are involved in protein synthesis, the nucleus (Choice B) stores genetic material and controls cell activities, and the endoplasmic reticulum (Choice D) plays a role in protein synthesis, lipid metabolism, and detoxification, but none of these structures are directly responsible for producing ATP.

3. Melanin, the pigment responsible for skin color, is produced by

• A. Keratinocytes (These cells produce keratin)
• B. Melanocytes
• C. Sebocytes (These cells produce sebum)
• D. Langerhans cells (These cells are part of the immune system)

Correct answer: B

Rationale: Melanocytes are the cells responsible for producing melanin, the pigment that determines skin color. Melanin gives skin its color and protects it from the harmful effects of UV radiation. Keratinocytes produce keratin, a tough protein that forms the outer layer of the skin, hair, and nails. Sebocytes produce sebum, an oily substance that helps moisturize and protect the skin. Langerhans cells are a type of immune cell found in the skin that play a role in protecting against infections and foreign substances but do not produce melanin.

4. Two isotopes of the same element have different numbers of:

• A. Electrons
• B. Protons
• C. Neutrons
• D. Nuclei

Correct answer: C

Rationale: The correct answer is C: 'Neutrons.' Isotopes are variants of an element that have the same number of protons and electrons but differ in the number of neutrons they contain. This difference in neutron count is what distinguishes isotopes from each other while maintaining the same chemical properties. Choice A, 'Electrons,' is incorrect because isotopes of the same element have the same number of electrons. Choice B, 'Protons,' is incorrect because isotopes of the same element have the same number of protons. Choice D, 'Nuclei,' is incorrect as nuclei refer to the central part of an atom containing protons and neutrons, and the question specifically asks about differences between isotopes of the same element.

5. Based on the following evidence, what is the most likely reason that spoiled food left out in the open often contains fly larvae?

• A. The spoiled food evolves into fly larvae.
• B. Since the food is left out in the open, flies lay eggs in the food.
• C. Fly larvae are spontaneously generated by the spoiled food.
• D. People only imagine they see fly larvae in the spoiled food.

Correct answer: B

Rationale: The correct answer is B. Flies laying eggs in the food when it is left exposed to the air is a common occurrence and a logical explanation for the presence of fly larvae in spoiled food. Choice A is incorrect as food cannot evolve into fly larvae; fly larvae come from eggs laid by flies. Choice C is incorrect as fly larvae do not spontaneously generate from spoiled food but rather develop from eggs laid by flies. Choice D is incorrect as the presence of fly larvae in spoiled food is a real phenomenon, not merely imagined by people.

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