Nokea
Which enzyme catalyzes the addition of deoxynucleotides to the 3'OH ends of DNA molecules?
- A. Phosphohydrolase
- B. T4 DNA ligase
- C. Terminal deoxynucleotidyl transferase
- D. DNA endonuclease
Correct Answer: C
Rationale: The correct answer is C: Terminal deoxynucleotidyl transferase (TdT). TdT catalyzes the addition of deoxynucleotides to the 3'OH ends of DNA molecules. It does so by adding nucleotides in a template-independent manner, making it crucial for generating diversity in immune cell receptor genes.
A: Phosphohydrolase - This enzyme is not involved in adding deoxynucleotides to DNA ends.
B: T4 DNA ligase - This enzyme catalyzes the joining of DNA fragments, not the addition of deoxynucleotides.
D: DNA endonuclease - This enzyme cleaves DNA internally, not involved in adding deoxynucleotides to DNA ends.
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What is hypersensitivity in immunology?
- A. An excessive or inappropriate immune response causing tissue damage
- B. The body's inability to mount an immune response
- C. A low-level immune reaction to antigens
- D. A mechanism for faster immune response during infections
Correct Answer: A
Rationale: Step-by-step rationale:
1. Hypersensitivity in immunology refers to an exaggerated or inappropriate immune response.
2. This excessive response can lead to tissue damage and various immune-mediated conditions.
3. Choice A accurately describes this concept.
Summary:
- Choice A is correct as it accurately defines hypersensitivity.
- Choice B is incorrect as hypersensitivity involves an exaggerated immune response, not an inability to mount one.
- Choice C is incorrect as hypersensitivity is not a low-level immune reaction.
- Choice D is incorrect as hypersensitivity is not a mechanism for faster immune response, but rather an overreaction.
Which of the following is a characteristic of the constant region of a T cell receptor?
- A. Mediates antigen binding
- B. Anchors the receptor in the T cell membrane
- C. Interacts with MHC molecules
- D. Structurally diverse amongst all T cell receptors
Correct Answer: B
Rationale: The correct answer is B: Anchors the receptor in the T cell membrane. The constant region of a T cell receptor is responsible for anchoring the receptor in the T cell membrane, providing stability and structural support. This region does not mediate antigen binding (choice A), as that function is carried out by the variable region. It also does not directly interact with MHC molecules (choice C), which is primarily the role of the variable region. Lastly, the constant region is not structurally diverse amongst T cell receptors (choice D), as it remains relatively consistent within a specific T cell subtype.
The nurse provides care to older adults. What should the nurse recognize as being more likely to occur in an older adult than in a younger adult?
- A. High fevers
- B. Fewer infections
- C. More autoimmune disorders
- D. Greater antibody production
Correct Answer: C
Rationale: The correct answer is C: More autoimmune disorders. As individuals age, the immune system weakens, leading to an increased risk of autoimmune disorders where the immune system mistakenly attacks healthy cells. This is more likely in older adults compared to younger adults. High fevers (choice A) are not more likely in older adults, as fever response tends to decrease with age. Fewer infections (choice B) are also less likely in older adults due to a weakened immune response. Greater antibody production (choice D) is not a characteristic of aging, as antibody production may decline with age.
Innate behaviors are
- A. under strong genetic control
- B. performed in virtually the indifferent way by all individuals of a species
- C. Sociobiology
- D. the environment
Correct Answer: A
Rationale: The correct answer is A because innate behaviors are indeed under strong genetic control. These behaviors are instinctual and are genetically programmed in organisms. This genetic control ensures that all individuals of a species exhibit these behaviors consistently. Choice B is incorrect because while innate behaviors may be performed similarly by individuals of a species, there can still be variations. Choice C, Sociobiology, is incorrect as it is a branch of biology that studies social behavior in animals. Choice D, the environment, is incorrect as innate behaviors are not primarily influenced by the environment but rather by genetic factors.
The nurse is caring for a patient who works as a legal secretary. The patient asks the nurse about ways to avoid developing carpal tunnel syndrome (CTS). Which action should the nurse suggest?
- A. "Exercise your wrists with repetitive flexion movements nightly."
- B. "Wrap your wrists with elastic bandages."
- C. "Acquire a pad to support your wrists while typing."
- D. "Apply warm compresses to wrists every evening."
Correct Answer: C
Rationale: The correct answer is C: "Acquire a pad to support your wrists while typing." This is the best option as wrist supports can help maintain neutral wrist positioning, reducing strain on the median nerve and decreasing the risk of developing CTS.
A: "Exercise your wrists with repetitive flexion movements nightly." - This can actually worsen the symptoms of CTS by putting more strain on the wrists.
B: "Wrap your wrists with elastic bandages." - Elastic bandages do not provide the necessary support and may restrict blood flow.
D: "Apply warm compresses to wrists every evening." - While warm compresses can provide temporary relief for symptoms, they do not address the underlying cause of CTS.