Nursing Elites

1. Which type of joint allows for rotational movement around a single axis?

• A. Ball-and-socket joint
• B. Pivot joint
• C. Hinge joint
• D. Saddle joint

Correct answer: B

Rationale: The correct answer is a Pivot joint. A pivot joint, like the joint in the neck, enables rotational movement around a single axis. This type of joint is crucial for allowing the head to turn from side to side. Choice A, Ball-and-socket joint, allows for movement in multiple axes due to its spherical structure, not limited to single-axis rotation. Choice C, Hinge joint, allows movement in one plane like a door hinge, but not rotational movement around a single axis. Choice D, Saddle joint, allows movement in multiple directions but is not specifically designed for rotational movement around a single axis.

2. What happens to the force of gravity between two objects when the distance between them is doubled?

• A. The force increases by a factor of 2
• B. The force increases by a factor of 4
• C. The force decreases by a factor of 2
• D. The force decreases by a factor of 4

Correct answer: D

Rationale: According to the law of universal gravitation, the force of gravity between two objects is inversely proportional to the square of the distance between them. When the distance is doubled, the force decreases by a factor of 2 squared, which is 4. Therefore, the force decreases by a factor of 4. Choice A is incorrect because the force doesn't increase when the distance is doubled. Choice B is incorrect as the force doesn't increase but actually decreases. Choice C is incorrect as the force decreases by a factor of 4, not 2.

3. What property of matter explains why ice floats on water?

• A. Viscosity
• B. Density
• C. Buoyancy
• D. Surface tension

Correct answer: C

Rationale: The correct answer is C, buoyancy. Ice floats on water due to buoyancy, a property of matter. When water freezes into ice, it becomes less dense than liquid water, causing it to float. This phenomenon occurs because the molecules in ice are more spread out compared to liquid water, resulting in ice being less dense and able to float on the surface. Choice A, viscosity, is incorrect because viscosity refers to a fluid's resistance to flow, not its ability to float. Choice B, density, is incorrect because while ice being less dense than water is the reason it floats, this choice does not explain the specific property that causes this phenomenon. Choice D, surface tension, is incorrect as it pertains to the cohesive forces between molecules at the surface of a liquid, not the reason why ice floats on water.

4. How are sister chromatids distinguished from homologous chromosomes in meiosis I?

• A. Sister chromatids share the same centromere, while homologous chromosomes have different centromeres.
• B. Sister chromatids have identical DNA sequences, while homologous chromosomes have slightly different sequences due to crossing over.
• C. Sister chromatids repel each other, while homologous chromosomes attract each other during synapsis.
• D. Sister chromatids separate during anaphase I, while homologous chromosomes separate during anaphase II.

Correct answer: B

Rationale: In meiosis I, sister chromatids are exact copies of each other, containing identical DNA sequences. On the other hand, homologous chromosomes are pairs of chromosomes, with one inherited from each parent, and they can have different versions of genes due to genetic recombination during crossing over in prophase I. Choice A is incorrect because homologous chromosomes naturally have different centromeres. Choice C is incorrect as sister chromatids and homologous chromosomes do not exhibit repulsion or attraction during synapsis. Choice D is incorrect as sister chromatids separate during anaphase II, not anaphase I, while homologous chromosomes separate during anaphase I.

5. What substance is required to drive the sliding filament process during muscle contraction?

• A. ATP
• B. Hormone
• C. Potassium
• D. Water

Correct answer: A

Rationale: The substance required to drive the sliding filament process during muscle contraction is ATP (adenosine triphosphate). ATP provides the energy needed for muscle contraction by enabling the myosin heads to bind to actin and generate force. This energy release drives the sliding of the filaments, causing muscle fibers to contract. Hormones, potassium, and water do not directly drive the sliding filament process in muscle contraction. Hormones are signaling molecules that regulate various physiological processes but do not directly provide energy for muscle contraction. Potassium is an electrolyte important for nerve and muscle function but is not the primary driver of the sliding filament process. Water is essential for overall hydration and bodily functions but does not directly participate in the muscle contraction process.

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