Nursing Elites

1. What are organisms that break down dead organisms and return nutrients to the environment called?

• A. Producers
• B. Decomposers
• C. Consumers
• D. Parasites

Correct answer: B

Rationale: Decomposers are essential organisms in the ecosystem as they break down dead organisms and organic matter, such as bacteria, fungi, and some insects. By decomposing complex organic materials into simpler forms, they release nutrients back into the environment for other organisms to utilize. Producers (option A) are organisms that generate their own food through photosynthesis; consumers (option C) are organisms that feed on other organisms for energy, and parasites (option D) are organisms that live on or in another organism, benefiting at the host's expense rather than breaking down dead organisms for nutrient recycling.

2. What is the process by which ribosomes use transcribed RNA to assemble the required protein?

• A. Translation
• B. Transcription
• C. Replication
• D. Duplication

Correct answer: A

Rationale: Translation is the correct process where ribosomes decode mRNA to synthesize proteins, following the sequence of codons in the mRNA. During translation, ribosomes use the transcribed RNA (mRNA) as a template to assemble amino acids into a protein according to the genetic code carried by the mRNA. Choice B, Transcription, is incorrect as it is the process of synthesizing mRNA from a DNA template. Choice C, Replication, is also incorrect as it involves the duplication of DNA to produce an identical copy. Choice D, Duplication, is not a biological term related to protein synthesis, making it an incorrect choice.

3. The chemical equation below is unbalanced. When it is properly balanced, how many molecules of carbon dioxide (CO2) are produced for each molecule of propane (C3H8) in the reaction? 3C3H8 + 5O2 → 3CO2 + 4H2O

• A. One Half.
• B. Two.
• C. Three.
• D. Five.

Correct answer: B

Rationale: The balanced chemical equation for the combustion of propane is: 3C3H8 + 5O2 → 3CO2 + 4H2O. This equation shows that for every 3 molecules of propane (C3H8) consumed, 3 molecules of carbon dioxide (CO2) are produced. Therefore, when properly balanced, 3CO2 are produced for each molecule of propane used. Thus, the correct answer is B: Two. Choices A, C, and D are incorrect because they do not reflect the correct stoichiometry as determined by the balanced equation.

4. What unit is used for measuring luminous flux, which indicates the perceived brightness of a light source by the human eye?

• A. Candela
• B. Lumen
• C. Lux
• D. Hertz

Correct answer: B

Rationale: Lumen is the correct unit for measuring luminous flux, which quantifies the total visible light emitted by a source per unit of time. Candela measures luminous intensity, lux measures illuminance, and Hertz measures frequency. Therefore, in the context of measuring the perceived brightness of a light source by the human eye, luminous flux is quantified in lumens.

5. What is the difference between active and passive immunity?

• A. Active immunity is short-lived, while passive immunity is long-lasting.
• B. Active immunity involves the body's own immune response, while passive immunity provides immediate protection through antibodies from another source.
• C. Active immunity only protects against bacterial infections, while passive immunity works against both bacteria and viruses.
• D. Passive immunity requires repeated vaccinations, while active immunity is a one-time process.

Correct answer: B

Rationale: Active immunity involves the body's own immune response, where the individual's immune system produces antibodies in response to exposure to a pathogen or vaccine. This type of immunity is long-lasting because the immune system 'remembers' the pathogen and can mount a rapid response upon re-exposure. In contrast, passive immunity provides immediate protection through the transfer of pre-formed antibodies from another source, such as through maternal antibodies crossing the placenta or receiving antibodies through an injection. Passive immunity is short-lived because the transferred antibodies eventually degrade and are not produced by the recipient's immune system. Choice A is incorrect because active immunity is generally long-lasting, as it involves the production of antibodies by the individual's immune system. Choice C is incorrect as both active and passive immunity can work against various pathogens, not limited to bacteria or viruses. Choice D is incorrect as passive immunity does not require repeated vaccinations but provides temporary protection through the transfer of antibodies from an external source.

Similar Questions