Nursing Elites

1. What effect does a catalyst have on a chemical reaction?

• A. It speeds up the reaction.
• B. It slows down the reaction.
• C. It makes a reaction go in reverse.
• D. It prevents a reaction from taking place.

Correct answer: A

Rationale: A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. It works by providing an alternate pathway for the reaction to occur, lowering the activation energy needed for the reaction to proceed. As a result, more reactant molecules can overcome this energy barrier and participate in the reaction, leading to a faster overall reaction rate. This explanation contradicts choices B, C, and D as a catalyst does not slow down, reverse, or prevent a reaction; instead, it accelerates the reaction by facilitating a more efficient route for the reaction to take place. Therefore, the correct answer is that a catalyst speeds up the reaction.

2. What is the term for the transfer of energy through a food chain?

• A. Photosynthesis
• B. Cellular respiration
• C. Transpiration
• D. Trophic cascade

Correct answer: D

Rationale: Rationale: A) Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll. B) Cellular respiration is the process by which cells break down glucose and other molecules to produce energy in the form of ATP. C) Transpiration is the process by which water is absorbed by plant roots, moves through the plant, and is released as vapor through pores in the leaves. D) Trophic cascade refers to the transfer of energy through a food chain or food web, where the impact of a predator on its prey cascades down the food chain, affecting multiple trophic levels. This term describes the indirect effects that predators can have on lower trophic levels, influencing the entire ecosystem.

3. Which of the following enzymes unwinds the double-stranded DNA during replication?

• A. Helicase
• B. Ligase
• C. Nuclease
• D. Polymerase

Correct answer: A

Rationale: Helicase is the enzyme responsible for unwinding the double-stranded DNA during replication by breaking the hydrogen bonds between the base pairs. This process creates the replication fork where DNA polymerase can then synthesize new DNA strands. Ligase functions to join Okazaki fragments on the lagging strand, not unwind DNA. Nuclease is involved in DNA repair by removing damaged DNA segments. Polymerase is responsible for synthesizing new DNA strands based on the existing template strands, not for unwinding the DNA.

4. Where does gas exchange take place in the respiratory system?

• A. Alveoli
• B. Bronchioles
• C. Bronchi
• D. Trachea

Correct answer: A

Rationale: Gas exchange in the respiratory system occurs in the alveoli, which are tiny air sacs in the lungs. Within the alveoli, oxygen from the inhaled air diffuses into the bloodstream, while carbon dioxide from the blood enters the alveoli to be exhaled. This exchange of gases is essential for the body to obtain oxygen and remove carbon dioxide, supporting vital bodily functions. The bronchioles (choice B), bronchi (choice C), and trachea (choice D) are part of the airway passage system that transports air to and from the alveoli but do not participate in gas exchange. Therefore, the alveoli play a crucial role in the respiratory system by facilitating gas exchange.

5. What is the name of the curved bone in the back that provides support and attachment for muscles?

• A. Sternum
• B. Scapula
• C. Clavicle
• D. Vertebral column

Correct answer: D

Rationale: The vertebral column, also known as the spine, is the curved bone in the back that provides support and attachment for muscles. It consists of individual vertebrae stacked on top of each other, forming a flexible and protective structure for the spinal cord. The sternum, scapula, and clavicle are bones in the chest and shoulder regions, not in the back where the vertebral column is located. Therefore, the correct answer is the vertebral column (Option D). Options A, B, and C are incorrect as they are bones situated in the chest and shoulder areas, not in the back where the vertebral column is found.

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