1. Which protein complex in the sarcomere is responsible for the thick filament?

A. Actin
B. Myosin
C. Tropomyosin
D. Troponin

Correct answer: B

Rationale: The correct answer is B: Myosin. In the sarcomere, the thick filament is composed of myosin protein. Myosin is responsible for the interaction with actin filaments during muscle contraction, forming cross-bridges that generate the force required for muscle movement. Actin (choice A) is a component of the thin filament in the sarcomere, while tropomyosin (choice C) and troponin (choice D) are regulatory proteins associated with muscle contraction but are not part of the thick filament. Understanding the specific components of the sarcomere is crucial for comprehending muscle contraction mechanisms.

2. What does the term "dilution" refer to in a solution?

A. Adding more solvent to decrease concentration
B. Adding more solute to increase concentration
C. Reducing the temperature to increase solubility
D. Increasing pressure to increase solubility

Correct answer: A

Rationale: Dilution involves adding more solvent to a solution to decrease the concentration of solute. The other choices do not accurately describe dilution

3. The primary function of the atrioventricular (AV) node within the heart is to:

A. Generate the electrical impulse for contraction (pacemaker function)
B. Transmit the electrical impulse from atria to ventricles, regulating the timing of contraction.
C. Increase blood pressure within the ventricles during systole.
D. Separate oxygenated and deoxygenated blood flow in the heart.

Correct answer: B

Rationale: The correct answer is B: "Transmit the electrical impulse from atria to ventricles, regulating the timing of contraction." The AV node acts as a gateway between the atria and ventricles, ensuring a coordinated and sequential contraction of the heart chambers. It delays the conduction of electrical impulses to allow the atria to fully contract before the ventricles contract, facilitating efficient blood pumping. Options A, C, and D are incorrect because the primary role of the AV node is not to generate electrical impulses, increase blood pressure, or separate blood flow based on oxygenation status. Understanding the AV node's function is crucial in comprehending the heart's electrical conduction system.

4. Stephanie is often seen interacting with the medical intern during coffee breaks and after duty

A. Formal
B. Informal
C. Staff
D. Line

Correct answer: B

Rationale: The correct answer is 'B: Informal.' Stephanie's interactions with the medical intern during coffee breaks and after duty suggest a casual and friendly relationship, rather than a formal or official one. 'Informal' describes interactions that are relaxed, personal, and not bound by strict professional protocols. In contrast, 'formal' interactions would involve more structured and official communication, such as meetings or professional discussions. 'Staff' and 'line' are not relevant in this context, as they do not describe the nature of the relationship between Stephanie and the medical intern.

5. Which sentence uses the colon correctly?

A. I brought snacks: chips, salsa, and guacamole.
B. The winner is: Sarah!
C. He loves all things chocolate: cake, ice cream, and candy bars.
D. Please bring the following items: pen, paper, and stapler.

Correct answer: A

Rationale: Colons are used to introduce a list or explanation that follows an independent clause. Options (a) and (c) use the colon correctly.

6. Why are isotopes of the same element chemically similar?

A. They have the same number of protons.
B. They have the same number of electrons.
C. Their chemical properties are identical.
D. They share the same electron configuration.

Correct answer: A

Rationale: They have the same number of protons. This determines the element's identity and its interactions with other elements, leading to similar chemical behavior, even if the number of neutrons differs.