Nursing Elites

1. What type of molecule forms the cell membrane and controls what enters and exits the cell?

• A. Proteins
• B. Carbohydrates
• C. Lipids
• D. Nucleic acids

Correct answer: C

Rationale: The cell membrane is primarily composed of lipids, specifically phospholipids, which form a lipid bilayer. This lipid bilayer controls what enters and exits the cell, providing a barrier that is selectively permeable. While proteins are also important components of the cell membrane and play various roles, lipids are the main structural component responsible for the membrane's permeability and function. Carbohydrates and nucleic acids are not the primary components of the cell membrane and do not have the same structural role as lipids.

2. What is the difference between heat and temperature?

• A. They are the same thing.
• B. Heat is a form of energy, while temperature measures the average kinetic energy of particles.
• C. Heat flows from cold to hot, while temperature flows from hot to cold.
• D. Heat is measured in Celsius, while temperature is measured in Joules.

Correct answer: B

Rationale: Heat and temperature are distinct concepts. Heat is a form of energy that transfers from a higher temperature object to a lower temperature object, while temperature represents the average kinetic energy of particles in a substance. Heat is quantified in units like Joules or calories, whereas temperature is typically gauged in degrees Celsius or Fahrenheit. Therefore, choice B correctly distinguishes between heat and temperature, making it the correct answer. Choices A, C, and D are incorrect because they do not accurately define the difference between heat and temperature. Choice A erroneously suggests they are the same, choice C confuses the direction of heat and temperature flow, and choice D provides inaccurate units for measuring heat and temperature.

3. A ball is thrown upwards. Which of the following statements is TRUE about its potential energy and kinetic energy at the peak of its trajectory?

• A. Both potential and kinetic energy are zero.
• B. Potential energy is maximum and kinetic energy is minimum.
• C. Potential energy is minimum and kinetic energy is maximum.
• D. Both potential and kinetic energy remain constant.

Correct answer: B

Rationale: At the peak of its trajectory, the ball momentarily stops moving before falling back down. This means its kinetic energy is at a minimum because it has come to a stop. At the same time, its potential energy is at a maximum because it is at the highest point in its trajectory, where it has the most potential to fall and convert that potential energy into kinetic energy as it descends. Choice A is incorrect because at the peak, the ball still has potential energy due to its height. Choice C is incorrect because kinetic energy is at a minimum when the ball is momentarily at rest. Choice D is incorrect because the energy conversion between potential and kinetic energy occurs at different points in the trajectory.

4. Chromatids divide into identical chromosomes and migrate to opposite ends of the cell in which of the following phases of mitosis?

• A. metaphase
• B. anaphase
• C. prophase
• D. telophase

Correct answer: B

Rationale: During anaphase of mitosis, the sister chromatids detach from each other and migrate to opposite poles of the cell. This process ensures that each daughter cell ultimately receives an identical set of chromosomes, as the chromatids separate and become individual chromosomes again. This is a crucial step in ensuring accurate distribution of genetic material during cell division. In metaphase, the chromosomes align at the cell's equator but do not separate yet. Prophase is the phase where chromatin condenses into chromosomes and the nuclear envelope breaks down. Telophase is the final phase where the nuclear envelope reforms around the separated chromosomes.

5. What are the microscopic units responsible for muscle contraction called?

• A. Neurons
• B. Myofibrils
• C. Tendons
• D. Sarcomeres

Correct answer: D

Rationale: Sarcomeres are the fundamental contractile units of skeletal muscles and are responsible for muscle contraction. They consist of actin and myosin filaments that slide past each other during muscle contraction. Neurons are responsible for transmitting signals to and from muscles but are not directly involved in muscle contraction. Myofibrils are composed of sarcomeres and are the structures within muscle cells where muscle contractions take place. Tendons are connective tissues that attach muscles to bones and are not directly involved in muscle contraction.

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