Nursing Elites

1. The phrase "disruptions to ecosystems" refers to

• A. Minor inconveniences experienced by plant and animal species due to changing weather patterns.
• B. Significant changes in ecological relationships and imbalances in populations and food webs.
• C. The aesthetic alteration of landscapes due to melting glaciers and deforestation.
• D. The economic losses suffered by industries relying on natural resources affected by climate change.

Correct answer: B

Rationale: The phrase suggests profound impacts on ecological balance and species interactions, aligning with B.

2. What is the valve that prevents blood from flowing back from the left ventricle into the left atrium?

• A. Tricuspid valve
• B. Mitral valve
• C. Aortic valve
• D. Pulmonic valve

Correct answer: B

Rationale: The correct answer is B: Mitral valve. The mitral valve, also known as the bicuspid valve, is located between the left atrium and the left ventricle. Its primary function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. The tricuspid valve is located between the right atrium and right ventricle, the aortic valve is located between the left ventricle and the aorta, and the pulmonic valve is located between the right ventricle and the pulmonary artery. Therefore, the mitral valve is specifically responsible for preventing backflow in the left side of the heart, making it the correct answer.

3. In a neutral atom, the number of electrons:

• A. Must be equal to the number of protons.
• B. Must be less than the number of protons.
• C. Must be greater than the number of neutrons.
• D. Can vary depending on the atom's temperature.

Correct answer: A

Rationale: Must be equal to the number of protons - For electrical neutrality, the positive charge of protons must be balanced by the negative charge of an equal number of electrons.

4. In what way does spindle fiber dynamics and microtubule attachment regulate cell cycle checkpoints?

• A. Misaligned chromosomes fail to attach to microtubules, triggering a delay in anaphase onset.
• B. The presence of unattached kinetochores on the centromeres sends a signal to pause cell cycle progression.
• C. Microtubule instability and rapid depolymerization lead to the activation of checkpoint proteins.
• D. All of the above.

Correct answer: D

Rationale: Rationale: A) Misaligned chromosomes fail to attach to microtubules, triggering a delay in anaphase onset: During cell division, proper attachment of chromosomes to spindle fibers is crucial for accurate segregation of genetic material. If chromosomes are not correctly attached to microtubules, it can lead to misalignment, which triggers a delay in anaphase onset. This delay allows the cell to correct any errors before proceeding with cell division. B) The presence of unattached kinetochores on the centromeres sends a signal to pause cell cycle progression: Kinetochores are protein structures located at the centromere of chromosomes and are responsible for attaching chromosomes to spindle fibers. When kinetochores are unattached or improperly attached to microtubules, it sends a signal to the cell to pause cell cycle progression. This pause allows the cell to ensure that all chromosomes are properly aligned before proceeding with cell division.

5. Saliva contains an enzyme that breaks down carbohydrates. What is the name of this enzyme?

• A. Pepsin
• B. Amylase
• C. Lipase
• D. Trypsin

Correct answer: B

Rationale: The correct answer is B: Amylase. Saliva contains the enzyme amylase, which is responsible for breaking down carbohydrates into simpler sugars like maltose and glucose. Pepsin (A) is an enzyme found in the stomach that breaks down proteins. Lipase (C) is an enzyme that breaks down fats, and trypsin (D) is another enzyme that breaks down proteins, but both of these are not found in saliva. Knowing the function of amylase in saliva helps in the digestion of carbohydrates, making it the correct answer.

6. Muscles that work together to produce a specific movement are called

• A. Antagonistic muscles
• B. Agonistic muscles
• C. Synergistic muscles
• D. Flexors and extensors

Correct answer: C

Rationale: Synergistic muscles are the correct answer because they are muscles that work together to produce a specific movement. These muscles coordinate their actions to achieve a common goal, such as bending the elbow or extending the knee. Antagonistic muscles work in opposition to each other, while agonistic muscles are the primary movers in a particular movement. Flexors and extensors refer to specific muscle groups that perform opposing actions, rather than working together synergistically. Understanding the concept of synergistic muscles is essential in biomechanics and exercise science.

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