Nursing Elites

1. What is the energy required to break a chemical bond called?

• A. Kinetic energy
• B. Potential energy
• C. Activation energy
• D. Bond energy

Correct answer: C

Rationale: Activation energy is the energy required to break a chemical bond and initiate a chemical reaction. It is the minimum amount of energy needed to start a chemical reaction by breaking bonds in the reactant molecules. Kinetic energy (option A) is the energy of motion and is not directly related to breaking chemical bonds. Potential energy (option B) is stored energy that can be converted into other forms of energy but is not specifically about breaking chemical bonds. Bond energy (option D) refers to the energy required to break a particular chemical bond in a molecule and is not the general term for the energy needed to break any chemical bond. Activation energy is crucial in determining the rate of a chemical reaction as it affects the probability of reactant molecules colliding with sufficient energy to surpass the energy barrier and form products.

2. What is a monohybrid cross, and what is the ratio of dominant to recessive gene manifestation?

• A. A cross involving two traits, 9:3:3:1
• B. A cross involving one trait, 3:1
• C. A cross involving two traits, 1:2:1
• D. A cross involving one trait, 1:1

Correct answer: B

Rationale: A monohybrid cross is a genetic cross involving one trait. The ratio of dominant to recessive gene manifestation in the offspring is typically 3:1 when both parents are heterozygous. This ratio is the genotypic ratio, not just the phenotype ratio, where the dominant allele is present in 3 out of 4 offspring, and the recessive allele is present in 1 out of 4 offspring. Choice A is incorrect because it describes a dihybrid cross ratio. Choice C is incorrect as it represents the genotypic ratio for a monohybrid cross involving incomplete dominance. Choice D is incorrect as it does not reflect the typical ratio for a monohybrid cross.

3. During which phase of the cell cycle does cytokinesis typically occur?

• A. Interphase
• B. Mitosis
• C. Meiosis
• D. G2 phase

Correct answer: B

Rationale: Cytokinesis is the process of dividing the cytoplasm of a cell into two daughter cells after the nucleus has divided during mitosis. In the cell cycle, cytokinesis typically occurs at the end of the mitotic phase, following the separation of the duplicated chromosomes into two identical sets in the daughter nuclei. Interphase (option A) is the phase where the cell grows, carries out its normal functions, and prepares for cell division, but cytokinesis does not occur during this phase. Meiosis (option C) is a specialized type of cell division that occurs in sexually reproducing organisms to produce gametes, and cytokinesis occurs at the end of meiosis II, not meiosis I. G2 phase (option D) is the phase of the cell cycle following DNA replication in S phase and preceding mitosis, where the cell prepares for cell division, but cytokinesis occurs during mitosis, not in the G2 phase.

4. How can a concave mirror be used?

• A. Focus light to a single point
• B. Create only virtual images
• C. Always magnify objects
• D. Scatter light

Correct answer: A

Rationale: A concave mirror can be used to focus light to a single point. This property is known as converging light rays to a focal point. When light rays parallel to the principal axis strike a concave mirror, they converge at a specific point called the focal point. This ability to focus light makes concave mirrors useful in applications such as reflecting telescopes and shaving mirrors. Choice B is incorrect because concave mirrors can create both real and virtual images, depending on the object's position relative to the mirror. Choice C is incorrect as concave mirrors can magnify, reduce, or maintain the size of objects, depending on the object's position and the distance from the mirror. Choice D is incorrect as concave mirrors do not scatter light but instead have the ability to reflect and focus light to produce clear images.

5. What are the finger-like projections that increase the surface area for absorption in the small intestine called?

• A. Crypts of Lieberkühn
• B. Goblet cells
• C. Villi
• D. Paneth cells

Correct answer: C

Rationale: A) Crypts of Lieberkühn are small pits in the lining of the small intestine that contain cells involved in the production of intestinal juices, but they do not increase the surface area for absorption. B) Goblet cells are specialized cells that secrete mucus to protect the lining of the digestive tract, but they do not increase the surface area for absorption. C) Villi are finger-like projections in the small intestine that increase the surface area available for nutrient absorption. Each villus contains blood vessels and lacteals (lymphatic vessels) that help absorb nutrients from digested food. D) Paneth cells are specialized cells found in the small intestine that secrete antimicrobial substances, but they do not increase the surface area for absorption.

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