Nursing Elites

1. What is the result when a single zygote separates into two parts, each developing into a separate individual?

• A. Dizygotic twin
• B. Monozygotic twin
• C. Fraternal twin
• D. Nonidentical twin

Correct answer: B

Rationale: The correct answer is B, Monozygotic twin. A monozygotic twin, also known as an identical twin, is the result when a single zygote splits into two parts, leading to the development of two genetically identical individuals. Choices A, C, and D are incorrect because they do not accurately describe the scenario where a single zygote splits into two parts to form identical twins. Dizygotic twin (Choice A) refers to fraternal twins, which result from two separate eggs fertilized by two different sperm cells. Fraternal twin (Choice C) is another term for dizygotic twins, arising from two separate zygotes. Nonidentical twin (Choice D) is a synonymous term for dizygotic or fraternal twins, indicating that they are not genetically identical.

2. Why is it particularly useful to study identical twins who were raised in different environments?

• A. Differences in brain function can be easily identified.
• B. Concordance rates tend to be higher.
• C. It is possible that the genetics of twins who have been separated have changed in ways to explain any differences found.
• D. It is possible that high concordance rates between identical twins reared together are due to their being treated more similarly than nonidentical twins.

Correct answer: D

Rationale: Studying identical twins raised in different environments allows researchers to understand the impact of genetics versus environmental factors on traits. Choice A is incorrect because differences in brain function can be influenced by a variety of factors and not solely by environmental differences. Choice B is incorrect as concordance rates tend to be higher in identical twins reared together due to shared genetics and environment. Choice C is incorrect because genetics do not change due to being raised in different environments.

3. In order for one to have a recessive trait (e.g., having red hair), the person must receive?

• A. At least one copy of a recessive gene from a parent
• B. Two copies of a recessive gene, one from each parent
• C. At least one copy of a recessive gene and at least one copy of a dominant gene
• D. At least two copies of a recessive gene from one parent

Correct answer: B

Rationale: Recessive traits are expressed when an individual inherits two copies of the recessive gene, one from each parent. Therefore, the correct answer is B. Choice A is incorrect as one copy of a recessive gene is not sufficient to display a recessive trait. Choice C is incorrect because having at least one copy of a dominant gene is unrelated to expressing a recessive trait. Choice D is incorrect because two copies of a recessive gene must come from both parents, not just one.

4. The site of chemical communication in the brain is the ________.

• A. neuron
• B. synapse
• C. axon
• D. dendrite

Correct answer: B

Rationale: The synapse is the correct answer. It is the site where communication between neurons occurs through the release and reception of neurotransmitters. Choice A, neuron, is incorrect as it is the cell itself rather than a specific site of communication. Choice C, axon, is also incorrect as it is a part of the neuron that transmits signals away from the cell body. Choice D, dendrite, is not the correct answer either, as dendrites receive signals from other neurons but do not release neurotransmitters for communication.

5. Neural plasticity is ________.

• A. the process by which neurotransmitters are broken down in the brain.
• B. the flexibility of the brain—existing neural circuits can change or new ones can be made.
• C. strong evidence of brain damage, leading to the development of a mental disorder.
• D. the best indicator of temperament and its effect on the personality development of a child.

Correct answer: B

Rationale: Neural plasticity refers to the brain's flexibility to change existing neural circuits or create new ones. Choice A is incorrect as it describes neurotransmitter breakdown, not neural plasticity. Choice C is incorrect because neural plasticity does not necessarily indicate brain damage leading to mental disorders. Choice D is incorrect because neural plasticity is not specifically related to temperament or personality development in children.

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