Nursing Elites

1. Why do high-salt content foods not require refrigeration to prevent spoilage?

• A. Osmosis
• B. Diffusion
• C. Active transport
• D. Passive transport

Correct answer: A

Rationale: Osmosis is the natural process that prevents high-salt content foods from spoiling without the need for refrigeration. Osmosis involves the movement of water across a semi-permeable membrane from an area of lower solute concentration (water) to an area of higher solute concentration (salt). In high-salt content foods, the salt acts as a preservative by drawing moisture out of bacteria or other microorganisms, making it difficult for them to survive and spoil the food. This process helps in preserving the food and preventing spoilage even without refrigeration. Choices B, C, and D are incorrect because they do not involve the specific mechanism of water movement in response to the salt concentration in high-salt content foods.

2. Which of the following is an example of human error in an experiment?

• A. an imperfectly calibrated scale
• B. contaminating a sterile sample by breathing on it
• C. a draft in the laboratory slightly changing the temperature of a liquid
• D. failure to account for wind speed when measuring distance traveled

Correct answer: B

Rationale: Contaminating a sterile sample by breathing on it is an example of human error in an experiment because it involves an action directly caused by the researcher that compromises the integrity of the sample. Breathing on a sterile sample introduces external contaminants that can affect the results. Choices A, C, and D involve factors not directly under the researcher's control or are technical errors that do not involve direct human actions.

3. Which two bases are purines?

• A. Adenine (A)
• B. Cytosine (C)
• C. Thymine (T)
• D. Guanine (G)

Correct answer: A

Rationale: Adenine (A) and guanine (G) are the two bases that are purines. Purines are characterized by a double-ring structure containing two carbon rings, distinguishing them from pyrimidines. Adenine and guanine are purines because they possess this unique double-ring structure. Therefore, choices A and D, adenine and guanine, respectively, are the correct answers. Choices B and C, cytosine and thymine, are pyrimidines and do not exhibit the double-ring structure characteristic of purines.

4. Which organelle is the site of photosynthesis in plant cells?

• A. Mitochondria
• B. Chloroplasts
• C. Ribosomes
• D. Endoplasmic Reticulum

Correct answer: B

Rationale: The correct answer is B: Chloroplasts. Chloroplasts are responsible for conducting photosynthesis in plant cells. They contain chlorophyll, a pigment that captures light energy and converts it into chemical energy through the process of photosynthesis. Mitochondria (choice A) are known as the powerhouse of the cell and are involved in cellular respiration, not photosynthesis. Ribosomes (choice C) are responsible for protein synthesis. The endoplasmic reticulum (choice D) is involved in protein and lipid synthesis and transport within the cell, not photosynthesis.

5. Which of the following describes how a bacterium reproduces?

• A. Mitosis
• B. Meiosis
• C. Binary fission
• D. Cytokinesis

Correct answer: C

Rationale: Bacteria reproduce through a process called 'binary fission.' During binary fission, a bacterium duplicates its DNA and then divides into two identical daughter cells. This method is the primary way bacteria replicate. Choice A, 'Mitosis,' is incorrect because mitosis is a process specific to eukaryotic cells, where the nucleus divides to produce two identical nuclei. Choice B, 'Meiosis,' is incorrect as meiosis is a specialized type of cell division that produces gametes with half the chromosome number. Choice D, 'Cytokinesis,' is not the correct answer as cytokinesis is the physical process of cell division, which occurs after the genetic material has been divided in mitosis or meiosis.

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