Nokea
A 69-year-old woman asks the nurse whether it is possible to 'catch' cancer because many of her friends of the same age have been diagnosed with different kinds of cancer. In responding to the woman, the nurse understands that what factor increases the incidence of tumors in older adults?
- A. An increase in autoantibodies
- B. Decreased activity of the bone marrow
- C. Decreased differentiation of T lymphocytes
- D. Decreased size and activity of the thymus gland
Correct Answer: D
Rationale: The thymus gland shrinks with age, reducing the production of new T cells, which impairs immune surveillance and increases cancer risk.
You may also like to solve these questions
The nurse is counseling a group of individuals over the age of 50 with average risk for cancer about screening tests for cancer. Which screening recommendation should be performed to screen for colorectal cancer?
- A. Barium enema every year
- B. Colonoscopy every 10 years
- C. Fecal occult blood every 5 years
- D. Annual prostate-specific antigen (PSA) and digital rectal exam
Correct Answer: B
Rationale: Colonoscopy every 10 years is recommended for colorectal cancer screening in individuals over 50 with average risk.
Which of the following enzymes removes 5' phosphate groups thereby preventing or decreasing the self-sealing of restricted plasmid vector molecules?
- A. Calf intestinal phosphatase
- B. Pyrophosphatase
- C. Phosphohydrolase
- D. phosphate exonuclease
Correct Answer: A
Rationale: The correct answer is A: Calf intestinal phosphatase. This enzyme removes 5' phosphate groups from DNA molecules, preventing self-ligation of restricted plasmid vectors. This step is crucial in generating linearized vectors for downstream applications. Pyrophosphatase (B) hydrolyzes pyrophosphate bonds, not 5' phosphate groups. Phosphohydrolase (C) is a general term for enzymes that hydrolyze phosphoester bonds, not specific to 5' phosphate removal. Phosphate exonuclease (D) degrades nucleic acids by removing nucleotides from the 3' end, not the 5' phosphate group.
What was Edward Jenner's major contribution to immunology?
- A. Discovering antibodies
- B. Proposing innate immunity theory
- C. Developing the smallpox vaccine
- D. Discovering the germ theory of disease
Correct Answer: C
Rationale: Edward Jenner's major contribution to immunology was developing the smallpox vaccine. He introduced the concept of vaccination by using cowpox to protect against smallpox. This marked the beginning of modern immunization. Discovering antibodies (A) and proposing innate immunity theory (B) were not directly attributed to Jenner. Discovering the germ theory of disease (D) was later proposed by Louis Pasteur and Robert Koch, not Jenner. Overall, choice C is correct as it aligns with Jenner's groundbreaking work in immunization.
Identify the incorrect statement
- A. There are ten times as many bacteria residing in the gut than human cells in the entire body
- B. Human babies, before birth, do not have commensal flora
- C. Studies on germ-free mice indicate that the microbiota is important for the development of the immune system
- D. A lower number of gut bacteria has been associated with obesity
Correct Answer: D
Rationale: The correct answer is D because a lower number of gut bacteria is not associated with obesity. In fact, research shows that an imbalance in gut bacteria, not a lower number, can contribute to obesity. Choice A is correct as there are indeed more bacteria in the gut than human cells in the body. Choice B is also correct as babies develop their commensal flora after birth. Choice C is correct, as studies on germ-free mice have shown the importance of microbiota in immune system development.
The intestinal epithelial cells that specialize in the production of antimicrobial peptides are called:
- A. Goblet cells
- B. Enterocytes
- C. Paneth cells
- D. Epithelial stem cells
Correct Answer: C
Rationale: The correct answer is C: Paneth cells. Paneth cells are specialized intestinal epithelial cells located in the small intestine that produce antimicrobial peptides to help defend against pathogens. They play a crucial role in maintaining gut homeostasis. Goblet cells (A) secrete mucus, enterocytes (B) absorb nutrients, and epithelial stem cells (D) are responsible for cell regeneration, but they do not produce antimicrobial peptides like Paneth cells do.