Nursing Elites

1. What is the shape of the DNA molecule?

• A. Linear
• B. Circular
• C. Double helix
• D. Straight chain

Correct answer: C

Rationale: The correct answer is C: Double helix. The shape of the DNA molecule is a double helix, a structure first described by James Watson and Francis Crick in 1953. This shape consists of two strands twisted around each other in a spiral. The double helix structure allows DNA to be compactly stored within the cell nucleus and provides stability to the molecule. Options (A) Linear, (B) Circular, and (D) Straight chain are incorrect as they do not accurately represent the shape of the DNA molecule. DNA is not linear but rather forms a twisted double helix; it is not circular like a ring but has a spiral structure, and it is not a straight chain but a twisted ladder-like structure.

2. What is the feedback mechanism in the endocrine system that helps maintain hormone balance?

• A. Positive feedback, where a hormone stimulates its own release
• B. Negative feedback, where a hormone suppresses its own release
• C. Cascade effect, where one hormone triggers the release of another
• D. Dual hormone system, where two hormones work together

Correct answer: B

Rationale: In the endocrine system, negative feedback is the mechanism by which hormone levels are regulated. When hormone levels reach a certain threshold, they signal the body to stop producing more of that hormone, thus maintaining a balance. Negative feedback (option B) is the correct answer as it helps in preventing overproduction of hormones by suppressing their own release. Positive feedback (option A) would lead to an excessive production of hormones, disrupting the balance. The cascade effect (option C) involves one hormone triggering the release of another but does not directly regulate hormone levels. The dual hormone system (option D) refers to two hormones working together but does not specifically address the feedback mechanism for maintaining hormone balance.

3. What is the process by which RNA molecules are modified after transcription but before translation?

• A. Replication
• B. Splicing
• C. Editing
• D. Packaging

Correct answer: B

Rationale: B) Splicing is the correct answer. Splicing is the process by which non-coding regions (introns) are removed from pre-mRNA, and the remaining coding regions (exons) are joined together to form mature mRNA. This modification occurs after transcription but before translation. A) Replication is incorrect as replication is the process by which DNA is copied to produce a new DNA molecule, not RNA modifications. C) Editing may involve RNA editing, but it is not commonly used to describe the modification of RNA molecules after transcription. D) Packaging is not the correct term as it refers to the condensation and organization of DNA into chromatin in eukaryotic cells, not the modification of RNA molecules.

4. How many daughter cells are formed from one parent cell during meiosis?

• A. One
• B. Two
• C. Three
• D. Four

Correct answer: D

Rationale: During meiosis, one parent cell produces four genetically distinct daughter cells. This occurs through two rounds of cell division, resulting in four haploid cells with half the number of chromosomes as the parent cell. Each daughter cell is genetically unique due to processes like crossing over and independent assortment during meiosis. Choice A is incorrect because meiosis results in multiple daughter cells. Choice B is incorrect because meiosis yields more daughter cells. Choice C is incorrect because meiosis produces four, not three, daughter cells.

5. How does kinetic energy change when the velocity of an object is doubled?

• A. Kinetic energy is halved
• B. Kinetic energy quadruples
• C. Kinetic energy doubles
• D. Kinetic energy remains the same

Correct answer: B

Rationale: Kinetic energy is directly proportional to the square of the velocity of an object according to the kinetic energy formula (KE = 0.5 * m * v^2). When the velocity is doubled, the kinetic energy increases by a factor of 2^2 = 4. Therefore, the kinetic energy quadruples when the velocity of an object is doubled. Choice A is incorrect because halving the kinetic energy would be the result if the velocity was halved, not doubled. Choice C is incorrect because doubling the velocity would result in a fourfold increase in kinetic energy, not just a double. Choice D is incorrect because kinetic energy is directly related to the velocity of an object, so if the velocity changes, the kinetic energy changes accordingly.

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