Nursing Elites

1. What does half-life refer to?

• A. Radioactive intensity to completely disappear
• B. The number of neutrons in a nucleus to double
• C. The number of protons in a nucleus to change
• D. An isotope to decay by half of its initial quantity

Correct answer: D

Rationale: Half-life refers to the time it takes for half of the radioactive atoms in a sample to decay. This means that after one half-life, half of the initial quantity of the radioactive substance will have decayed. Choice A is incorrect because radioactive intensity doesn't completely disappear during half-life. Choice B is incorrect as half-life doesn't refer to the number of neutrons doubling. Choice C is incorrect as half-life doesn't relate to the number of protons changing.

2. What are chromosomes made of?

• A. DNA and RNA
• B. DNA and protein
• C. Protein and RNA
• D. DNA and lipids

Correct answer: B

Rationale: Chromosomes are made up of DNA and associated proteins. These proteins help package and organize the DNA within the cell, playing a crucial role in gene regulation and cell division. While RNA is involved in various cellular processes, it is not a primary component of chromosomes. Lipids are not a fundamental component of chromosomes, which primarily consist of DNA and proteins.

3. What is the term for the process of separating the components of a solution based on their different rates of movement through a medium?

• A. Filtration
• B. Distillation
• C. Chromatography
• D. Precipitation

Correct answer: C

Rationale: Chromatography is the correct term for the process of separating the components of a solution based on their different rates of movement through a medium. In chromatography, the components move at different speeds due to their interactions with the medium, causing separation. Filtration involves using a barrier to separate solid particles from a liquid. Distillation separates components based on differences in boiling points to collect the vapor of the more volatile component. Precipitation refers to the formation of a solid from a solution by a chemical reaction or change in conditions.

4. Which of the following statements is NOT true about DNA?

• A. DNA contains the nucleotides A, T, C, G and is read 5' to 3'.
• B. DNA contains genetic information and is tightly coiled with proteins to form chromosomes.
• C. DNA contains the nucleotides A, T, C, G and is read 3' to 5'.
• D. DNA is a double-stranded molecule connected by hydrogen bonds.

Correct answer: C

Rationale: The correct answer is C because DNA is typically read from the 5' end to the 3' end, not from 3' to 5'. Choices A, B, and D are all true statements about DNA. DNA contains the nucleotides A, T, C, G and is read in a 5' to 3' direction. DNA also contains genetic information and is tightly coiled with proteins to form chromosomes. Additionally, DNA is a double-stranded molecule connected by hydrogen bonds.

5. Which of the following is NOT a method of sterilization?

• A. Autoclave
• B. UV light
• C. Chemical disinfectants
• D. Boiling water

Correct answer: D

Rationale: A) Autoclave: An autoclave is a method of sterilization that uses high pressure and steam to kill microorganisms, making it an effective way to sterilize equipment and materials.\nB) UV light: UV light is a method of sterilization that damages the DNA of microorganisms, preventing them from reproducing and causing infections.\nC) Chemical disinfectants: Chemical disinfectants are used to kill or inactivate microorganisms on surfaces, but they may not always achieve sterilization, which is the complete destruction of all microorganisms.\nD) Boiling water: Boiling water is a method of disinfection rather than sterilization. While boiling water can kill many microorganisms, it may not be effective against all types of bacteria, viruses, and spores, making it unsuitable for achieving sterilization.\n\nTherefore, the correct answer is D) Boiling water, as it is not a method of sterilization.

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