Nursing Elites

1. What is the small repeating unit in the contractile apparatus of skeletal muscle?

• A. Myofibril
• B. Actin
• C. Sarcomere
• D. Myosin

Correct answer: C

Rationale: The correct answer is 'Sarcomere.' The sarcomere is the smallest repeating unit within myofibrils and is responsible for muscle contraction in skeletal muscle. It consists of overlapping actin and myosin filaments arranged in a highly organized structure that allows for the sliding of filaments during muscle contraction. 'Myofibril' (choice A) is incorrect because it is a larger structure composed of sarcomeres. 'Actin' (choice B) and 'Myosin' (choice D) are incorrect as they are individual proteins that are components of the sarcomere, not the smallest repeating unit itself.

2. Which of the following substances is a common base found in household products?

• A. Sodium chloride (NaCl)
• B. Ammonia (NH₃)
• C. Vinegar
• D. Lemon juice

Correct answer: B

Rationale: The correct answer is B, Ammonia (NH₃). Ammonia is commonly found in household products and is used in cleaning agents due to its alkaline properties. Sodium chloride (NaCl) is a common salt and not a base. Vinegar is acetic acid, which is acidic in nature. Lemon juice contains citric acid, making it acidic as well. Therefore, ammonia is the only base among the choices provided.

3. What impact would the removal of a keystone species have in an ecosystem?

• A. Lead to a decrease in competition among other species
• B. Cause a slight increase in primary productivity
• C. Have a minimal impact on the overall ecosystem structure
• D. Disrupt the food web and cause cascading effects on other populations

Correct answer: D

Rationale: Keystone species play a crucial role in maintaining the balance and structure of an ecosystem due to their significant influence. If a keystone species is removed, it disrupts the delicate food web dynamics and can trigger cascading effects throughout the ecosystem. The disruption in predator-prey relationships can lead to population declines and even extinctions of other species. Options A, B, and C are incorrect because the removal of a keystone species would not decrease competition among other species, cause a slight increase in primary productivity, or have a minimal impact on the overall ecosystem structure. Instead, it would have a profound impact, disrupting the food web and causing cascading effects on other populations.

4. Which part of the heart receives oxygenated blood from the lungs?

• A. Left atrium
• B. Right atrium
• C. Left ventricle
• D. Right ventricle

Correct answer: A

Rationale: The correct answer is A, the left atrium. The left atrium receives oxygenated blood from the lungs, which is then pumped into the left ventricle and out to the rest of the body. The right atrium receives deoxygenated blood from the body and sends it to the right ventricle to be pumped to the lungs for oxygenation. Choices B, C, and D are incorrect as they do not directly receive oxygenated blood from the lungs.

5. What is the scientific name for the common housefly?

• A. Musca domestica
• B. Drosophila melanogaster
• C. Apis mellifera
• D. Anopheles gambiae

Correct answer: A

Rationale: Musca domestica is the scientific name for the common housefly. This species is known for being a common pest found in and around human habitations. Drosophila melanogaster (option B) is a species of fruit fly commonly used in genetic research. Apis mellifera (option C) is the scientific name for the western honeybee. Anopheles gambiae (option D) is a species of mosquito known for being a vector of malaria.

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