Nokea
Where and into what do activated B lymphocytes differentiate?
- A. Spleen; natural killer cells that destroy infected cells
- B. Bone marrow; plasma cells that secrete immunoglobulins
- C. Thymus; memory B-cells that retain a memory of the antigen
- D. Bursa of Fabricius; helper cells that in turn activate additional B lymphocytes
Correct Answer: B
Rationale: Activated B lymphocytes differentiate into plasma cells in the bone marrow, which produce and secrete antibodies.
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Which of the following early contributors to the development of immunology is paired up properly with his or her accomplishment?
- A. Louis Pasteur: demonstrated that cowpox vaccination can protect from smallpox
- B. Paul Ehrlich: identified lymphocytes as the cells mediating adaptive immunity
- C. MacFarlane Burnet: proposed the side-chain theory of antibodies which suggested that multiple antigen receptors are expressed on immune cells
- D. Robert Koch: developed techniques to grow pure bacterial cultures
Correct Answer: D
Rationale: Rationale: Robert Koch is correctly paired with developing techniques to grow pure bacterial cultures. Koch's work laid the foundation for bacteriology and allowed for the isolation and identification of specific disease-causing bacteria. This technique, known as Koch's postulates, revolutionized the field of microbiology by linking specific pathogens to specific diseases.
Summary:
A: Louis Pasteur - Incorrect. While Pasteur is known for his work in vaccination and pasteurization, the provided accomplishment is associated with Edward Jenner, not Pasteur.
B: Paul Ehrlich - Incorrect. Ehrlich is known for his work on immunology and coined the term "magic bullet," but he did not identify lymphocytes as cells mediating adaptive immunity.
C: MacFarlane Burnet - Incorrect. Burnet is known for his clonal selection theory, not the side-chain theory of antibodies as described in the choice.
What is a primary reason that the normal immune response fails to contain the HIV infection?
- A. CD4+ T cells become infected with HIV and are destroyed.
- B. The virus inactivates B cells, preventing the production of HIV antibodies.
- C. Natural killer cells are destroyed by the virus before the immune system can be activated.
- D. Monocytes ingest infected cells, differentiate into macrophages, and shed viruses in body tissues.
Correct Answer: A
Rationale: HIV specifically targets CD4+ T cells, depleting the immune system's ability to mount an effective response against pathogens.
A small molecule that combines with a specific allosteric protein so that both prevent RNA polymerase activity is called a(n):
- A. inducer
- B. repressor
- C. corepressor
- D. leader
Correct Answer: C
Rationale: The correct answer is C: corepressor. A corepressor is a small molecule that binds to an allosteric protein to inhibit its activity. In this case, the corepressor prevents RNA polymerase activity. The other choices are incorrect because:
A: Inducer activates gene expression.
B: Repressor inhibits gene expression by binding to DNA.
D: Leader is not a term related to allosteric regulation.
Which condition is associated with increased susceptibility to bacterial infections due to complement deficiencies?
- A. Asthma
- B. Systemic lupus erythematosus (SLE)
- C. Streptococcus pneumoniae infections
- D. Chronic hepatitis
Correct Answer: C
Rationale: The correct answer is C: Streptococcus pneumoniae infections. Complement deficiencies impair the body's ability to fight bacterial infections, particularly encapsulated bacteria like Streptococcus pneumoniae. Asthma (A), SLE (B), and chronic hepatitis (D) are not directly associated with increased susceptibility to bacterial infections due to complement deficiencies. Asthma is a chronic respiratory condition, SLE is an autoimmune disease, and chronic hepatitis affects the liver. Therefore, only Streptococcus pneumoniae infections are directly linked to complement deficiencies.
A patient is scheduled to have a tunneled catheter placed for administration of chemotherapy for breast cancer. When preparing the patient for the catheter insertion, what does the nurse explain about this method of chemotherapy administration?
- A. Decreases the risk for extravasation at the infusion site
- B. Reduces the incidence of systemic side effects of the drug
- C. Does not become occluded as peripherally inserted catheters can
- D. Allows continuous infusion of the drug directly to the area of the tumor
Correct Answer: A
Rationale: Tunneled catheters reduce extravasation risks compared to peripheral lines by delivering medications centrally.