Nursing Elites

1. Which of the following is unique to covalent bonds?

• A. Most covalent bonds are formed between the elements H, F, N, and O.
• B. Covalent bonds are dependent on forming dipoles.
• C. Bonding electrons are shared between two or more atoms.
• D. Molecules with covalent bonds tend to have a crystalline solid structure.

Correct answer: C

Rationale: The correct answer is C: 'Bonding electrons are shared between two or more atoms.' This statement is unique to covalent bonds. In covalent bonds, atoms share electrons to achieve a stable electron configuration, which leads to the formation of a bond. This sharing of electrons is a fundamental characteristic of covalent bonds and distinguishes them from other types of chemical bonds, such as ionic bonds, where electrons are transferred rather than shared. Choices A, B, and D do not represent unique characteristics of covalent bonds. Choice A describes some common elements involved in covalent bonds, choice B refers to the concept of dipoles, which can also exist in other types of bonds, and choice D describes a property of molecules (crystalline solid structure) that is not exclusive to covalent bonds.

2. Which of the following meninges is a thin membrane containing numerous nerves and blood vessels that supply nourishment to the underlying brain cells and spinal cord?

• A. Arachnoid mater
• B. Dura mater
• C. Periosteum
• D. Pia mater

Correct answer: D

Rationale: The pia mater is the correct answer. It is a thin, innermost layer of the meninges that contains numerous nerves and blood vessels, providing nourishment to the underlying brain cells and spinal cord. The arachnoid mater (Choice A) is the middle layer of the meninges and does not contain as many nerves and blood vessels as the pia mater. The dura mater (Choice B) is the tough, outermost layer of the meninges and is not responsible for supplying nourishment. The periosteum (Choice C) is a connective tissue membrane covering bones, not part of the meninges.

3. Which of the following structures is responsible for transmitting electrical impulses in the nervous system?

• A. Neuron
• B. Axon
• C. Myelin
• D. Dendrite

Correct answer: A

Rationale: The correct answer is A: Neuron. Neurons are specialized cells that transmit electrical impulses in the nervous system. While the axon is the part responsible for conducting these impulses over long distances, it is the neuron as a whole that is ultimately responsible for transmitting electrical impulses. Myelin is a fatty substance that surrounds and insulates axons, speeding up signal transmission. Dendrites, on the other hand, receive signals from other neurons. Therefore, although the axon plays a significant role in transmission, the neuron is the fundamental unit responsible for transmitting electrical impulses in the nervous system.

4. What is the term for a genetic disorder caused by a mutation in a mitochondrial gene?

• A. Autosomal dominant disorder
• B. Autosomal recessive disorder
• C. Sex-linked disorder
• D. Mitochondrial disorder

Correct answer: D

Rationale: A) Autosomal dominant disorder: This type of genetic disorder is caused by a mutation in one copy of an autosomal gene. It is not related to mitochondrial gene mutations. B) Autosomal recessive disorder: This type of genetic disorder is caused by mutations in both copies of an autosomal gene. It is not related to mitochondrial gene mutations. C) Sex-linked disorder: This type of genetic disorder is caused by mutations in genes located on the sex chromosomes (X or Y). It is not related to mitochondrial gene mutations. D) Mitochondrial disorder: Mitochondrial disorders are genetic disorders caused by mutations in genes located in the mitochondria, the energy-producing structures within cells. These disorders are inherited maternally and can affect various organs and systems in the body due to the role of mitochondria in energy production.

5. Which condition involves an overactive immune system attacking healthy tissues, leading to inflammation and damage?

• A. Immunodeficiency
• B. Autoimmune disease
• C. Allergy
• D. Cancer

Correct answer: B

Rationale: Autoimmune diseases occur when the immune system mistakenly targets and attacks healthy tissues in the body, leading to inflammation and damage. This is different from immunodeficiency, where the immune system is weakened and unable to effectively protect the body against infections. Allergies involve an exaggerated immune response to harmless substances, while cancer is characterized by uncontrolled cell growth. Therefore, the correct answer is autoimmune disease (Choice B) as it specifically describes the scenario of an overactive immune system attacking healthy tissues, distinguishing it from the other conditions listed.

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