Nursing Elites

1. 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 the Mitral valve. The mitral valve is located between the left atrium and the left ventricle of the heart. Its function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. Choice A, the Tricuspid valve, is incorrect as it is located between the right atrium and right ventricle. Choice C, the Aortic valve, and Choice D, the Pulmonic valve, are also incorrect as they are involved in the circulation of blood leaving the heart rather than preventing backflow within the atria and ventricles.

2. What is the main function of peroxisomes in the cell?

• A. To break down hydrogen peroxide
• B. To synthesize lipids and other cellular components
• C. To package and transport proteins
• D. To store genetic material

Correct answer: A

Rationale: Peroxisomes are membrane-bound organelles found in eukaryotic cells that contain enzymes involved in various metabolic processes. One of the main functions of peroxisomes is to break down hydrogen peroxide, a toxic byproduct of metabolism, into water and oxygen through the action of the enzyme catalase. This process helps protect the cell from oxidative damage caused by hydrogen peroxide. While peroxisomes are involved in other metabolic functions such as lipid metabolism and the synthesis of bile acids, their primary role is the breakdown of hydrogen peroxide. Choices B, C, and D are incorrect because peroxisomes are not primarily responsible for synthesizing lipids, packaging and transporting proteins, or storing genetic material within the cell.

3. Homologous structures are similar structures in different organisms that have a common evolutionary origin. An example is:

• A. Butterfly wings and bird wings (analogous structures with different origins)
• B. The arm of a human, the wing of a bat, and the flipper of a whale
• C. The eyes of an octopus and a human (convergent evolution with different origins)
• D. The stinger of a bee and the barb of a cactus (unrelated structures)

Correct answer: B

Rationale: Homologous structures are similar structures found in different organisms that share a common evolutionary origin. The arm of a human, the wing of a bat, and the flipper of a whale are all examples of homologous structures. Despite serving different functions, they share a common underlying structure due to their evolutionary relationship, evidencing a shared ancestry. These structures are modified over time to suit the specific needs of each species. Option A (Butterfly wings and bird wings) refers to analogous structures with different origins. Option C (The eyes of an octopus and a human) describes convergent evolution where traits evolve independently. Option D (The stinger of a bee and the barb of a cactus) are unrelated structures.

4. What is the main function of dietary fiber in the digestive system?

• A. To provide energy
• B. To break down fats
• C. To promote gut bacteria growth
• D. To aid in absorption of nutrients

Correct answer: C

Rationale: Dietary fiber refers to the indigestible portion of plant foods that passes relatively intact through the digestive system. While fiber does not directly provide energy to the body, it plays a crucial role in promoting the growth of beneficial gut bacteria. These bacteria help in the fermentation of fiber, producing short-chain fatty acids that can be used as an energy source by the body. Additionally, fiber aids in regulating bowel movements, maintaining gut health, and supporting overall digestive function. The functions described in the incorrect choices do not align with the primary role of dietary fiber in the digestive system. Choice A is incorrect because fiber itself is not a direct energy source. Choice B is incorrect as fiber does not break down fats. Choice D is incorrect because while fiber affects nutrient absorption indirectly by supporting gut health, its primary role is not to aid in the absorption of nutrients.

5. Which macromolecules are composed of nucleotides and store information and energy?

• A. Lipids
• B. Proteins
• C. Carbohydrates
• D. Nucleic acids

Correct answer: D

Rationale: The correct answer is D: Nucleic acids. Nucleic acids, such as DNA and RNA, are composed of nucleotides and are responsible for storing genetic information and energy (e.g., ATP). Lipids, proteins, and carbohydrates are distinct macromolecules with varying functions and structures. Lipids primarily serve as energy reservoirs, structural components, and cell signaling molecules. Proteins play crucial roles in cellular functions like enzyme activity, structural support, and intracellular signaling. Carbohydrates are mainly utilized as an energy source and for structural purposes within cells.

Similar Questions