Nursing Elites

1. During which of the following stages does crossing over occur?

• A. Mitosis Prophase
• B. Meiosis Prophase I
• C. Meiosis Prophase II
• D. Interphase

Correct answer: B

Rationale: Crossing over occurs during Prophase I of meiosis. This stage is specifically associated with genetic recombination, where homologous chromosomes exchange genetic material. This process contributes to genetic diversity by creating new combinations of alleles. Choices A, C, and D are incorrect. In mitosis, crossing over does not occur as it involves the separation of replicated chromosomes. Meiosis Prophase II is focused on the reformation of nuclei and does not involve crossing over. Interphase is a stage where the cell prepares for division and is not associated with crossing over.

2. Positron emission tomography (PET) scans utilize a key property of positrons for medical imaging. What is this property?

• A. High mass
• B. Positive charge
• C. Extreme stability
• D. Identical behavior to electrons

Correct answer: B

Rationale: Positron emission tomography (PET) scans utilize the property of positrons having a positive charge. Positrons are the antimatter counterpart of electrons, having the same mass but opposite charge. When a positron collides with an electron, they annihilate each other, producing gamma rays that can be detected by the PET scanner to create images of the body's internal structures and functions. Choice A is incorrect because positrons have the same mass as electrons. Choice C is incorrect as positrons are not extremely stable due to their tendency to annihilate when they encounter electrons. Choice D is incorrect as positrons exhibit different behavior than electrons due to their opposite charges.

3. Which of the following is NOT a type of epithelium?

• A. Stratified squamous
• B. Simple cuboidal
• C. Stratified columnar
• D. Pseudostratified columnar

Correct answer: D

Rationale: The correct answer is D, Pseudostratified columnar. Pseudostratified columnar epithelium is not a type of epithelium. It is a specialized form of simple columnar epithelium. Stratified squamous, simple cuboidal, and stratified columnar are all types of epithelial tissues found in the human body. Stratified squamous epithelium is found in the skin, mouth, and esophagus; simple cuboidal epithelium lines kidney tubules and glands; stratified columnar epithelium is present in parts of the respiratory tract and male urethra.

4. What is the microscopic functional unit of the kidney responsible for filtering blood?

• A. Ureter
• B. Nephron
• C. Renal pelvis
• D. Bladder

Correct answer: B

Rationale: The nephron is the correct answer as it is the microscopic functional unit of the kidney responsible for filtering blood. It is composed of a renal corpuscle (glomerulus and Bowman's capsule) and a renal tubule. The other options, such as (A) Ureter, (C) Renal pelvis, and (D) Bladder, do not play a role in filtering blood within the kidney. The ureter is a tube that carries urine from the kidney to the bladder. The renal pelvis is a part of the kidney where urine collects before entering the ureter. The bladder is an organ that stores urine until it is excreted from the body.

5. What does the P-wave in an ECG correspond to?

• A. Atrial repolarization
• B. Depolarization of SA node
• C. Ventricular depolarization
• D. Ventricular repolarization

Correct answer: B

Rationale: The P-wave in an ECG represents the depolarization of the SA node and the atria, not atrial repolarization. Choice C, ventricular depolarization, is incorrect because the P-wave does not correspond to ventricular activity. Choice D, ventricular repolarization, is also incorrect as the P-wave does not depict ventricular repolarization. The correct interpretation is that the P-wave signifies the initiation of the electrical impulse at the SA node and subsequent atrial depolarization, making option B the correct answer.

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