Nursing Elites

1. Which of the following molecules is an important component of the plasma membrane?

• A. Phospholipids
• B. Steroids
• C. Sugars
• D. Amino acids

Correct answer: A

Rationale: Phospholipids are indeed a crucial component of the plasma membrane. They have a unique structure with hydrophilic heads and hydrophobic tails, which allows them to form the lipid bilayer of the membrane. Steroids, sugars, and amino acids are not primary components of the plasma membrane. Steroids are a different type of lipid, sugars are often found in glycoproteins on the membrane surface, and amino acids are the building blocks of proteins, some of which are membrane proteins, but not the membrane itself.

2. Which of the following is false?

• A. Animal cells use lysosomes to break down old cells
• B. Animal cells use chloroplasts to gain energy
• C. Plant cells have a cell wall to maintain structure
• D. All of the above are true

Correct answer: B

Rationale: The statement "B. Animal cells use chloroplasts to gain energy" is false. Chloroplasts are only present in plant cells and certain algae, where they are responsible for photosynthesis to generate energy from sunlight. Animal cells rely on other organelles, such as mitochondria, for energy production. Choice A is true because animal cells use lysosomes to break down old cells and cellular waste. Choice C is true as plant cells have a cell wall composed of cellulose that provides structural support and protection.

3. Three students measured the mass of a product of combustion. They recorded measurements of 14 g, 16 g, and 17 g. If the known mass of the product is 30 g, how would you describe the students’ measurements?

• A. Accurate
• B. Precise
• C. Both accurate and precise
• D. Neither accurate nor precise

Correct answer: B

Rationale: The students' measurements are precise because they are consistently close to each other. However, they are not accurate because all the measurements deviate from the known mass of the product (30 g). Accuracy refers to how close a measurement is to the true or accepted value, while precision refers to the level of agreement among repeated measurements. Since the students' measurements are consistent but do not align with the true value, they can be considered precise but not accurate. Choice A is incorrect because accuracy relates to the proximity of the measurements to the true value, which is not the case here. Choice C is incorrect because although the measurements are precise, they are not accurate. Choice D is incorrect because the measurements are precise as they show good agreement with each other, even though they are not accurate.

4. What is necessary for active transport through a membrane to take place?

• A. Glucose
• B. Oxygen
• C. Sodium
• D. ATP

Correct answer: D

Rationale: Active transport through a membrane requires energy in the form of ATP (adenosine triphosphate). ATP provides the necessary energy for the transport proteins to move molecules against the concentration gradient, from an area of lower concentration to higher concentration. This process is essential for maintaining cellular functions and regulating the internal environment of a cell. Glucose, oxygen, and sodium are important molecules involved in various cellular processes, but they are not the primary energy source required for active transport across membranes. Therefore, the correct answer is ATP.

5. Which part of a plant’s reproductive system is of a different “gender” than the others?

• A. Stamen
• B. Pistil
• C. Stigma
• D. Style

Correct answer: A

Rationale: The stamen is the male reproductive organ of a plant, producing pollen grains. The pistil, consisting of the stigma, style, and ovary, is the female reproductive organ. Therefore, the stamen is of a different 'gender' than the other parts of the plant's reproductive system. The pistil, stigma, and style are all part of the female reproductive system, involved in receiving pollen and supporting fertilization. Stamen is the correct answer as it is the male part of a plant's reproductive system, making it different 'gender-wise' from the female parts.

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