Nursing Elites

1. During which developmental process does the first trimester of gestation roughly correspond?

• A. Embryogenesis
• B. Fertilization
• C. Meiosis
• D. Menstruation

Correct answer: A

Rationale: The correct answer is A: Embryogenesis. The first trimester of gestation involves the process of embryogenesis, where the basic structures of the embryo are formed. This period is critical for the development of major organ systems and the establishment of the embryo's overall body plan. Fertilization occurs at the beginning of pregnancy when the sperm fertilizes the egg, marking the start of embryonic development. Meiosis is a cell division process that produces gametes (sperm and egg cells) with half the number of chromosomes. Menstruation is the shedding of the uterine lining when pregnancy does not occur.

2. The Gram stain is a differential staining technique used to classify bacteria based on their cell wall composition. Gram-positive bacteria appear

• A. Pink
• B. Blue
• C. Red
• D. Purple

Correct answer: D

Rationale: The Gram stain is a differential staining technique that categorizes bacteria into two groups based on their cell wall composition: Gram-positive and Gram-negative. Gram-positive bacteria have a thick layer of peptidoglycan in their cell walls, which retains the crystal violet stain used in the Gram staining procedure. Consequently, Gram-positive bacteria appear purple under the microscope after staining. On the other hand, Gram-negative bacteria possess a thinner peptidoglycan layer and an outer membrane that can be penetrated by the counterstain safranin, leading them to appear pink or red. Blue is not typically used to describe the color of bacteria in a Gram stain, making it an incorrect choice.

3. What is the primary function of the CRISPR-Cas9 system in gene editing?

• A. To amplify specific DNA sequences.
• B. To cut DNA at specific locations.
• C. To deliver genes into cells.
• D. To sequence entire genomes.

Correct answer: B

Rationale: The CRISPR-Cas9 system is a powerful tool used in gene editing to precisely target and cut DNA at specific locations within the genome. This system consists of a guide RNA that directs the Cas9 enzyme to the desired DNA sequence, where it creates a double-strand break. This break can then be repaired by the cell's natural DNA repair mechanisms, allowing for the introduction of specific genetic modifications. Options A, C, and D are incorrect as they do not accurately describe the primary function of the CRISPR-Cas9 system in gene editing. Amplifying DNA sequences, delivering genes into cells, and sequencing entire genomes are not the main functions of the CRISPR-Cas9 system, which is primarily focused on precise DNA cutting for targeted genetic modifications.

4. Which blood vessels transport blood from the capillaries back to the heart?

• A. Arterioles
• B. Veins
• C. Venules
• D. Capillaries

Correct answer: B

Rationale: Veins are the correct answer as they are the blood vessels that carry blood from the capillaries back to the heart. Veins have thinner walls compared to arteries and contain valves to prevent blood from flowing backward. This transport of blood from the capillaries to the heart is essential for the circulatory system to maintain proper blood flow and oxygenation levels. Arterioles are small branches of arteries that lead to capillaries, not vessels that transport blood back to the heart. Venules are small vessels that collect blood from capillaries and lead to veins. Capillaries are the smallest blood vessels where the exchange of gases and nutrients occurs between blood and tissues, not vessels that transport blood back to the heart.

5. What does the term 'colligative property' refer to in solutions?

• A. Properties that depend on the nature of the solute particles
• B. Properties that depend on the concentration of solute particles
• C. Properties that depend on the temperature of the solution
• D. Properties that depend on the pressure of the solution

Correct answer: B

Rationale: Colligative properties are properties of a solution that depend on the concentration of solute particles, regardless of the identity of the solute. These properties include lowering the vapor pressure, elevation of boiling point, depression of freezing point, and osmotic pressure. The concentration of solute particles affects these properties, not the nature, temperature, or pressure of the solution. Therefore, choice B is the correct answer as it accurately reflects the definition of colligative properties. Choices A, C, and D are incorrect because colligative properties are not based on the nature, temperature, or pressure of the solute, but rather on the concentration of solute particles in the solution.

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