Nursing Elites

1. What is the purpose of phloem tissue in plant stems?

• A. It conducts water up through the stem.
• B. It conducts the energy of light to leaves.
• C. It conducts food throughout the plant.
• D. It conducts carbon dioxide throughout the plant.

Correct answer: C

Rationale: The purpose of phloem tissue in plant stems is to conduct food, particularly sugars produced in the leaves during photosynthesis, throughout the plant. The phloem transports these organic compounds to various parts of the plant where they are needed for growth and energy. Choice A is incorrect because water is primarily transported by xylem tissue, not phloem. Choice B is incorrect as the energy of light is captured by chlorophyll in the process of photosynthesis, not conducted by phloem. Choice D is incorrect because carbon dioxide is mainly absorbed through the leaves and transported to other parts of the plant through diffusion, not by phloem.

2. What is the main function of the cell membrane?

• A. Energy production
• B. Communication
• C. Protein synthesis
• D. Waste removal

Correct answer: B

Rationale: The main function of the cell membrane is communication. It acts as a barrier that regulates the passage of substances in and out of the cell, maintaining cellular homeostasis. Choices A, C, and D are incorrect because energy production occurs in the mitochondria, protein synthesis takes place in the ribosomes, and waste removal is primarily handled by the lysosomes and other organelles within the cell.

3. What are the two catabolic pathways that lead to cellular energy production?

• A. Fermentation and internal respiration
• B. Fermentation and external respiration
• C. Fermentation and cellular respiration
• D. Fermentation and anaerobic respiration

Correct answer: C

Rationale: The correct answer is 'Fermentation and cellular respiration.' Fermentation is an anaerobic catabolic process that occurs in the absence of oxygen, producing limited amounts of ATP. Cellular respiration, on the other hand, is the aerobic catabolic pathway that occurs in the presence of oxygen and is the most efficient way of producing ATP. Choices A, B, and D are incorrect because internal respiration, external respiration, and anaerobic respiration are not the correct pathways leading to cellular energy production.

4. Physical factors such as temperature and pH can alter enzyme activity because they have an effect on the enzyme's ___________.

• A. acidity
• B. shape
• C. chemistry
• D. substrate

Correct answer: B

Rationale: Physical factors such as temperature and pH can alter enzyme activity by affecting the enzyme's shape. Enzymes rely on their specific shapes to function properly and catalyze reactions. Any changes in temperature or pH can disrupt these shapes, causing the enzyme to become denatured and lose its functionality. Therefore, alterations in temperature and pH can impact enzyme activity by directly affecting their shapes. Choices A, C, and D are incorrect because while pH can affect acidity and chemical properties of the enzyme, and temperature can influence the enzyme-substrate interaction, the primary reason for enzyme activity alteration due to temperature and pH is the change in the enzyme's shape.

5. As cattle graze, cattle egrets consume the insects they stir up. This is an example of ___________.

• A. Mutualism
• B. Parasitism
• C. Commensalism
• D. Competition

Correct answer: C

Rationale: Commensalism is a relationship between two species in which one benefits without affecting the other species. In this scenario, the cattle egrets benefit from the insects stirred up by cattle while the cattle are not significantly impacted by the presence of the egrets. The egrets obtain food easily, and the cattle are neither harmed nor helped by the egrets' presence, making it an example of commensalism. Mutualism involves both species benefiting, parasitism involves one species benefiting at the expense of the other, and competition involves both species being negatively affected by their interactions, none of which apply to the relationship between cattle and cattle egrets in this context.

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