Nursing Elites

1. Sunscreen protects the skin from harmful ultraviolet (UV) rays by

• A. Reflecting UV rays away from the skin
• B. Absorbing UV rays and converting them to heat
• C. Blocking UV rays completely
• D. Stimulating melanin production

Correct answer: B

Rationale: The correct answer is B: Absorbing UV rays and converting them to heat. Sunscreen contains ingredients that act as filters to absorb UV radiation before it reaches the skin. These filters then convert the UV rays into a less harmful form of energy, usually heat, which is then released from the body. This process helps prevent UV radiation from damaging the skin cells and causing sunburn or long-term skin damage. Reflecting UV rays away from the skin (A) and blocking UV rays completely (C) are not accurate functions of sunscreen. Additionally, stimulating melanin production (D) is not a direct way in which sunscreen protects the skin from UV rays.

2. Which hormone, produced by the thyroid gland, plays a crucial role in regulating the body's metabolism, growth, and development?

• A. Calcitonin
• B. Parathyroid hormone (PTH)
• C. Thyroxine
• D. Insulin

Correct answer: c

Rationale: The correct answer is C: Thyroxine. Thyroxine, also known as T4, is a hormone produced by the thyroid gland that plays a crucial role in regulating the body's metabolism, growth, and development. It controls how the body uses energy, affects heart rate, and influences other vital functions. Calcitonin (A) is involved in calcium regulation, not metabolism. Parathyroid hormone (PTH) (B) is produced by the parathyroid glands and regulates calcium and phosphorus levels in the body. Insulin (D) is a hormone produced by the pancreas that regulates blood sugar levels, not metabolism or growth.

3. Which group of elements is known for their reactivity and ability to form strong bonds with other elements?

• A. Noble gases
• B. Halogens
• C. Alkali metals
• D. Transition metals

Correct answer: B

Rationale: Rationale: Halogens are a group of elements in the periodic table that are known for their high reactivity and ability to form strong bonds with other elements. They have seven valence electrons, which makes them highly reactive as they only need one more electron to achieve a stable electron configuration. Halogens readily form compounds with other elements by gaining an electron to achieve a full outer shell, resulting in the formation of strong covalent bonds. In contrast, noble gases (option A) are known for their inertness and stable electron configurations, alkali metals (option C) are highly reactive but not as strong bond formers as halogens, and transition metals (option D) are known for their variable oxidation states and ability to form complex ions but are not as reactive as halogens in terms of bond formation.

4. Which type of nuclear force is responsible for holding protons and neutrons together in the nucleus of an atom?

• A. Electromagnetism
• B. Gravity
• C. Strong nuclear force
• D. Weak nuclear force

Correct answer: C

Rationale: The incredibly powerful, strong nuclear force overcomes the repulsive electrostatic force between protons, binding them together and stabilizing the nucleus.

5. You design an experiment to test the effect of temperature on plant growth. Which variable should you keep constant?

• A. The type of soil used.
• B. The amount of sunlight the plants receive.
• C. The amount of water given to the plants.
• D. The temperature variations being tested.

Correct answer: A

Rationale: In this experiment, the variable being tested is the effect of temperature on plant growth. To ensure that any observed changes in plant growth are due to temperature variations and not other factors, it is important to keep other variables constant. The type of soil used can significantly impact plant growth, so it should be kept constant to isolate the effect of temperature. Keeping the amount of sunlight and water constant would also help ensure that any differences in plant growth are due to temperature variations.

6. What is the name of the regulatory region in a gene that controls its expression?

• A. Exon
• B. Intron
• C. Promoter
• D. Enhancer

Correct answer: C

Rationale: Rationale: A) Exon: Exons are the coding regions of a gene that are transcribed into mRNA and eventually translated into proteins. Exons do not regulate gene expression. B) Intron: Introns are non-coding regions of a gene that are removed during RNA processing and do not play a direct role in controlling gene expression. C) Promoter: The promoter is a regulatory region located at the beginning of a gene that initiates the process of transcription by binding transcription factors and RNA polymerase. It plays a crucial role in controlling gene expression. D) Enhancer: Enhancers are regulatory regions that can be located far from the gene they regulate and can increase the transcription of a gene. While enhancers are important for gene expression, the specific region that controls gene expression is the promoter. Therefore, the correct answer is C) Promoter, as it is the regulatory region in a gene that controls its expression by initiating transcription.

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