Nursing Elites

1. If every child in a certain family suffers from autism, what possible conclusion can be drawn about autism?

• A. Autism may be lethal.
• B. Autism may be genetic.
• C. Autism is related to traditional nuclear family structures.
• D. No conclusion can be drawn based on this evidence.

Correct answer: B

Rationale: The possible conclusion that can be drawn from every child in a certain family suffering from autism is that autism may be genetic. The fact that every child in the family has autism suggests a strong genetic influence on the condition within this particular family. This does not necessarily mean that autism is solely genetic in all cases, but in this specific family, the pattern of all children being affected points towards a genetic connection. Choice A is incorrect as the information provided does not suggest that autism is lethal. Choice C is incorrect as there is no evidence to support a relationship between autism and traditional nuclear family structures. Choice D is incorrect because a conclusion can be drawn from the given evidence, indicating a potential genetic link within this specific family.

2. Which of the following nucleobases does not exist in RNA?

• A. Uracil
• B. Thymine
• C. Cytosine
• D. Guanine

Correct answer: B

Rationale: The correct answer is 'B: Thymine'. Thymine is a nucleobase found in DNA but is replaced by uracil in RNA. RNA contains Uracil, Cytosine, and Guanine as its nucleobases. Cytosine and Guanine are present in both DNA and RNA, while Thymine is exclusive to DNA and Uracil is specific to RNA.

3. Which type of immune cell does the human immunodeficiency virus (HIV) target and destroy?

• A. Neutrophils
• B. Macrophages
• C. Helper T cells
• D. Memory B cells

Correct answer: C

Rationale: HIV targets and destroys Helper T cells, which are vital for coordinating the immune response against infections. The destruction of Helper T cells weakens the immune system, leading to acquired immunodeficiency syndrome (AIDS). Neutrophils (Choice A) are primarily involved in acute inflammatory responses and fighting bacterial infections. Macrophages (Choice B) play a role in phagocytosis and antigen presentation but are not the primary target of HIV. Memory B cells (Choice D) are responsible for mounting a quicker and more robust antibody response upon re-exposure to a pathogen, but they are not the main target of HIV infection.

4. What is the primary function of the myelin sheath that surrounds some axons in the nervous system?

• A. To initiate nerve impulses
• B. To transmit sensory information
• C. To speed up the transmission of nerve impulses
• D. To connect neurons at synapses

Correct answer: C

Rationale: The primary function of the myelin sheath is to speed up the transmission of nerve impulses. The myelin sheath acts as an insulating layer around the axon, allowing for faster conduction of electrical impulses along the nerve fiber. This insulation prevents the electrical signal from dissipating or 'leaking' out, which helps in the rapid and efficient transmission of nerve impulses along the axon. Choice A is incorrect because the myelin sheath does not initiate nerve impulses; it helps in conducting them. Choice B is incorrect as the myelin sheath's main role is not in transmitting sensory information but rather in facilitating the transmission of nerve impulses. Choice D is incorrect because the myelin sheath's function is not to connect neurons at synapses; instead, it is primarily involved in enhancing the speed of nerve impulse transmission.

5. Which statement accurately describes cytokinesis in animal cells?

• A. Which statement accurately describes cytokinesis in animal cells?
• B. A cell plate forms in the center of the dividing cell, eventually separating the cytoplasm into two daughter cells.
• C. A cell plate forms in the center of the dividing cell, eventually separating the cytoplasm into two daughter cells.
• D. The nucleus elongates and pulls apart, physically dividing the cytoplasm into two.

Correct answer: B

Rationale: A) This statement is a duplicate of option C and does not accurately describe cytokinesis in animal cells. B) In animal cells, during cytokinesis, a cleavage furrow forms in the center of the dividing cell. This furrow deepens and eventually pinches the cytoplasm into two daughter cells. This process is distinct from plant cells, where a cell plate forms. C) This statement is a duplicate of option A and does not accurately describe cytokinesis in animal cells. D) This statement describes the process of nuclear division (mitosis) rather than cytokinesis, which is the division of the cytoplasm.

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