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 correct answer is C: Lipids. The cell membrane is primarily composed of a double layer of lipids called phospholipids. These phospholipids have a hydrophilic (water-attracting) head and two hydrophobic (water-repelling) tails, which arrange themselves to form a barrier that controls the passage of substances in and out of the cell. While proteins are also present in the cell membrane and play important roles in transport and cell signaling, lipids are the main structural component responsible for the selective permeability of the membrane. Carbohydrates are typically found on the outer surface of the membrane and are involved in cell recognition and communication. Nucleic acids are not a major component of the cell membrane; they are primarily responsible for storing and transmitting genetic information within the cell.

2. In the context of the cardiac cycle, the P wave on an electrocardiogram (ECG) represents:

• A. Atrial depolarization
• B. Ventricular depolarization
• C. Atrial repolarization
• D. Ventricular repolarization

Correct answer: A

Rationale: The correct answer is A: "Atrial depolarization." The P wave on an ECG represents the depolarization of the atria, specifically the spread of electrical activity through the atria causing them to contract and push blood into the ventricles. This is the first wave observed on the ECG and signifies the beginning of the cardiac cycle. Ventricular depolarization is represented by the QRS complex, atrial repolarization is typically not visible on a standard ECG due to its timing with the QRS complex, and ventricular repolarization is represented by the T wave. Therefore, option A is the most appropriate choice in this context.

3. Long-term potentiation (LTP) is a process in the brain associated with:

• A. Sensory perception
• B. Memory formation
• C. Muscle control
• D. Emotional regulation

Correct answer: D

Rationale: Long-term potentiation (LTP) is a process in the brain that is primarily associated with memory formation. During LTP, the strength of synaptic connections between neurons is increased, which is crucial for encoding and storing memories. While sensory perception, muscle control, and emotional regulation involve different brain processes, LTP specifically plays a key role in the formation and retention of memories. Therefore, the correct answer is B: Memory formation.

4. Which of the following is NOT a function of the muscular system?

• A. Movement
• B. Maintaining posture
• C. Generating heat
• D. Regulating blood sugar levels

Correct answer: D

Rationale: The correct answer is D: "Regulating blood sugar levels." The muscular system primarily functions in movement, maintaining posture, and generating heat. Muscles contract and relax to allow movement and help us stay upright. They also produce heat through muscle contractions to maintain body temperature. Regulating blood sugar levels is primarily controlled by the endocrine system, specifically the pancreas and hormones like insulin and glucagon. Therefore, this function is not directly related to the muscular system.

5. What is the term for a substance that can act as both a proton donor and a proton acceptor?

• A. Acid
• B. Base
• C. Amphiprotic
• D. Neutral

Correct answer: C

Rationale: Amphiprotic substances can act as both a proton donor and a proton acceptor. The other choices are specific to either acids or bases.

6. A hypothesis should be:

• A. A definitive statement of fact based on existing knowledge.
• B. A testable prediction based on observations and reasoning.
• C. A broad question without any specific direction or focus.
• D. A personal belief or opinion not requiring further investigation.

Correct answer: B

Rationale: Hypotheses guide scientific exploration by providing a framework for testing potential explanations.

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