Nursing Elites

1. Which molecule allows for the selective passage of materials into and out of the cell?

• A. DNA
• B. Protein
• C. Carbohydrate
• D. Phospholipid bilayer

Correct answer: D

Rationale: The correct answer is D, the phospholipid bilayer. The phospholipid bilayer is the main component of the cell membrane, which acts as a selective barrier allowing certain molecules to pass through while blocking others. Its structure consists of hydrophilic heads facing outward towards the aqueous environments inside and outside the cell, while the hydrophobic tails face inward creating a semi-permeable barrier. DNA (A) is the genetic material of the cell and is located within the nucleus, not involved in material passage. Proteins (B) and carbohydrates (C) are important components of the cell membrane and play various roles, but they do not directly control the selective passage of materials in and out of the cell.

2. The adaptive immune system has two main branches: humoral and cell-mediated immunity. Which type of immune cell is primarily responsible for antibody production?

• A. Helper T cells
• B. Cytotoxic T cells
• C. B cells
• D. Natural killer cells

Correct answer: C

Rationale: The correct answer is C: B cells. B cells are a type of lymphocyte that plays a central role in humoral immunity by producing antibodies. When activated by antigens, B cells differentiate into plasma cells, which are responsible for producing and secreting antibodies. Helper T cells (option A) primarily assist in activating B cells and other immune cells. Cytotoxic T cells (option B) are involved in cell-mediated immunity, where they directly kill infected cells. Natural killer cells (option D) are part of the innate immune system and target virus-infected and cancerous cells. Therefore, B cells are the immune cells primarily responsible for antibody production in the adaptive immune system.

3. Which of the following phases of mitosis is characterized by the separation of sister chromatids and their movement to opposite poles?

• A. Metaphase
• B. Anaphase
• C. Anaphase
• D. Cytokinesis

Correct answer: B

Rationale: Rationale: During anaphase of mitosis, the sister chromatids, which are duplicated copies of a chromosome, separate and move towards opposite poles of the cell. This movement is facilitated by the shortening of microtubules attached to the chromatids. As a result, each pole of the cell receives a complete set of chromosomes, ensuring that the daughter cells produced after cell division will have the correct number of chromosomes. Metaphase is characterized by the alignment of chromosomes at the cell's equator, not their separation. Telophase is the phase following anaphase, where the separated chromatids reach the opposite poles and nuclear envelopes start to form around them. Cytokinesis is the final stage of cell division, where the cytoplasm is divided to form two separate daughter cells.

4. Which property of a substance refers to its ability to be stretched into thin wires?

• A. Conductivity
• B. Viscosity
• C. Ductility
• D. Malleability

Correct answer: c

Rationale: Ductility refers to a substance's ability to be stretched into thin wires without breaking.

5. The process of a gas changing directly into a solid is called:

• A. Condensation
• B. Deposition
• C. Sublimation
• D. Evaporation

Correct answer: B

Rationale: This process, also known as sublimation, involves gas particles losing energy and transitioning directly into the solid state.

6. Which gland in the endocrine system is responsible for the production of red blood cells?

• A. Pituitary gland
• B. Thyroid gland
• C. Thymus gland
• D. Parathyroid gland

Correct answer: C

Rationale: The correct answer is the Thymus gland (option C). The Thymus gland is responsible for the production and maturation of T-lymphocytes, a type of white blood cell involved in immune responses. Red blood cells are not produced by any endocrine gland; instead, they are produced in the bone marrow. The Pituitary gland (option A) secretes hormones that control various body functions, the Thyroid gland (option B) regulates metabolism, and the Parathyroid gland (option D) regulates calcium levels in the blood. Therefore, the Thymus gland is not responsible for the production of red blood cells, making it the correct answer in this case.

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