Nursing Elites

1. What protein complex controls the progression of mitosis through its activation and degradation?

• A. Ribosome
• B. Cyclin-dependent kinase (CDK)
• C. Centriole
• D. Microtubule

Correct answer: B

Rationale: A) Ribosome: Ribosomes are cellular organelles responsible for protein synthesis and are not directly involved in controlling the progression of mitosis. B) Cyclin-dependent kinase (CDK): CDKs are a family of protein kinases that regulate the cell cycle, including the progression of mitosis. CDK activity is controlled by cyclins, which bind to CDKs to activate them at specific points in the cell cycle. The activation and degradation of cyclins regulate the activity of CDKs, which in turn control the progression of mitosis. C) Centriole: Centrioles are involved in organizing the microtubules of the mitotic spindle but do not directly control the progression of mitosis. D) Microtubule: Microtubules are structural components of the cytoskeleton and are involved in various cellular processes, including mitosis, but they do not control

2. What is a rod-shaped structure that forms when a single DNA molecule and its associated proteins coil tightly before cell division?

• A. Centromere
• B. Chromatid
• C. Chromosome
• D. Gene

Correct answer: C

Rationale: A chromosome is a rod-shaped structure that forms when a single DNA molecule and its associated proteins coil tightly before cell division. It contains the genetic material and is essential for cell division and replication. The centromere is a specific region of a chromosome that plays a role in cell division. A chromatid is one half of a duplicated chromosome, and a gene is a unit of heredity responsible for specific traits. Therefore, the correct answer is 'Chromosome' as it represents the entire condensed DNA molecule during cell division.

3. 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.

4. Which of the following hormones would cause skin color to become darker?

• A. Follicle-stimulating
• B. Growth-stimulating
• C. Thyroid-stimulating
• D. Melanocyte-stimulating

Correct answer: D

Rationale: The correct answer is D, Melanocyte-stimulating. Melanocyte-stimulating hormone (MSH) stimulates melanocytes in the skin to produce more melanin, leading to darker skin pigmentation. Choices A, B, and C are incorrect as Follicle-stimulating hormone (FSH) stimulates follicle growth in the reproductive system, Growth-stimulating hormone is a vague term not specific to any known hormone, and Thyroid-stimulating hormone (TSH) stimulates the thyroid gland to produce thyroid hormones, not affecting skin color pigmentation.

5. Which of the following best describes the relationship among density, volume, and mass?

• A. As volume increases, density decreases.
• B. As volume decreases, density increases.
• C. An object's mass does not affect its density.
• D. As volume decreases, mass increases.

Correct answer: B

Rationale: The correct answer is B: 'As volume decreases, density increases.' This is because density is defined as mass divided by volume. When volume decreases and mass remains constant, the ratio of mass to volume increases, leading to higher density. Choice A is incorrect because as volume increases, density typically remains constant or increases due to the mass also increasing. Choice C is incorrect because an object's density is directly influenced by its mass. Choice D is incorrect as decreasing volume does not lead to an increase in mass.

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