Nursing Elites

1. In a single displacement reaction, one element takes the place of another element in a compound. Which of the following is an example?

• A. 2H2 + O2 -> 2H2O
• B. Zn + 2HCl -> ZnCl2 + H2
• C. CaCO3 -> CaO + CO2
• D. CH4 + 2O2 -> CO2 + 2H2O

Correct answer: B

Rationale: In a single displacement reaction, one element replaces another element in a compound. Option B, 'Zn + 2HCl -> ZnCl2 + H2,' is an example of a single displacement reaction where zinc (Zn) replaces hydrogen (H) in hydrochloric acid (HCl) to form zinc chloride (ZnCl2) and hydrogen gas (H2). The other options do not involve one element displacing another in a compound. Option A is a synthesis reaction, option C is a decomposition reaction, and option D is a combustion reaction. Therefore, option B is the correct answer as it demonstrates the concept of single displacement reactions.

2. Which of the following organelles is responsible for the production of proteins in the cell?

• A. Ribosomes
• B. Golgi apparatus
• C. Mitochondria
• D. Lysosomes

Correct answer: A

Rationale: The correct answer is A: Ribosomes. Ribosomes are the organelles responsible for protein synthesis in the cell. They are found in both prokaryotic and eukaryotic cells and can be free-floating in the cytoplasm or attached to the endoplasmic reticulum. Ribosomes read the messenger RNA (mRNA) and translate the genetic code into proteins through a process called translation. The Golgi apparatus is involved in processing and packaging proteins for secretion, while mitochondria are responsible for energy production. Lysosomes are involved in digestion and waste removal within the cell.

3. Which of the following is an example of a commensal relationship between a microorganism and a human?

• A. Salmonella causing food poisoning
• B. taphylococcus aureus causing skin infections
• C. coli living in the gut
• D. Rabies virus causing neurological disease

Correct answer: C

Rationale: Rationale: A commensal relationship is a type of symbiotic relationship in which one organism benefits, while the other is neither harmed nor benefited. In this case, E. coli living in the gut is an example of a commensal relationship because it can benefit from the environment in the gut without causing harm to the human host. Option A, Salmonella causing food poisoning, is an example of a pathogenic relationship where the microorganism causes harm to the host. Option B, Staphylococcus aureus causing skin infections, is also an example of a pathogenic relationship where the microorganism causes harm to the host. Option D, Rabies virus causing neurological disease, is another example of a pathogenic relationship where the microorganism causes harm to the host.

4. Which of the following is an example of a weak acid?

• A. Hydrochloric acid (HCl)
• B. Sulfuric acid (H2SO4)
• C. Acetic acid (CH3COOH)
• D. Nitric acid (HNO3)

Correct answer: C

Rationale: Weak acids only partially dissociate in water, releasing a lower concentration of hydrogen ions.

5. Electrons occupy specific energy levels around the nucleus with varying probabilities. The electron cloud model depicts electrons existing in distinct energy levels, not fixed orbits, with probabilities of finding them in specific regions.

• A. 2 protons and 6 neutrons
• B. 2 filled s orbitals and 6 filled p orbitals
• C. 2s orbitals with 2 and 6 electrons, respectively
• D. 4 filled electron shells

Correct answer: B

Rationale: 2 filled s orbitals and 6 filled p orbitals. This notation indicates two electrons in the 2s orbital and six electrons in the 2p orbitals.

6. The urethra is the tube that carries urine from the bladder to the outside of the body. How does urine flow through the urethra?

• A. Continuously
• B. Only when the bladder is completely full
• C. Under voluntary control of sphincter muscles
• D. A combination of b) and c)

Correct answer: C

Rationale: The correct answer is C: "Under voluntary control of sphincter muscles." The urethra is the tube responsible for carrying urine from the bladder to the outside of the body. Urine flow through the urethra is not continuous but rather under voluntary control. The sphincter muscles, located at the opening of the bladder and urethra, help control the release of urine. This control allows individuals to regulate when and where they empty their bladder, providing a mechanism to prevent involuntary leakage of urine. Therefore, option C accurately describes how urine flows through the urethra.

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