Which enzyme excises incorrect nucleotides on the newly synthesized DNA?
- A. DNA gyrase
- B. RNA primase
- C. DNA ligase
- D. DNA polymerase II
Correct Answer: E
Rationale: I'm sorry, but it seems like there was a mistake in the question as there is no option E provided. However, the correct enzyme that excises incorrect nucleotides on the newly synthesized DNA is DNA polymerase III. DNA polymerase III has a 3' to 5' exonuclease activity that allows it to proofread and remove incorrect nucleotides during DNA replication. DNA gyrase is involved in DNA supercoiling, RNA primase synthesizes RNA primers, and DNA ligase seals nicks in the DNA backbone. DNA polymerase II is involved in DNA repair.
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Which immune cells are primarily responsible for antibody production?
- A. Neutrophils
- B. Plasma cells (derived from B lymphocytes)
- C. Natural killer cells
- D. Macrophages
Correct Answer: B
Rationale: The correct answer is B: Plasma cells (derived from B lymphocytes). B lymphocytes are responsible for producing antibodies. When activated, B cells differentiate into plasma cells, which are specialized in secreting antibodies. Neutrophils are primarily involved in phagocytosis, not antibody production. Natural killer cells are involved in killing infected cells, not antibody production. Macrophages are phagocytic cells that present antigens to activate B lymphocytes but do not produce antibodies themselves. Therefore, the correct answer is B as plasma cells derived from B lymphocytes are primarily responsible for antibody production.
The patient is learning about skin care related to the external radiation that he is receiving. Which instructions should the nurse include in this teaching?
- A. Moisturize skin with lotion
- B. Keep the area covered if it is sore
- C. Dry the skin thoroughly after cleansing it
- D. Avoid extreme temperatures to the area
Correct Answer: D
Rationale: Avoiding extreme temperatures protects the radiated skin from further irritation.
Individuals unable to make the J protein found in certain immunoglobulins would be expected to have frequent infections of the
- A. intestinal tract
- B. blood.
- C. liver.
- D. pancreas.
Correct Answer: A
Rationale: The correct answer is A: intestinal tract. The J protein is crucial for the proper functioning of immunoglobulins in the mucosal immune system, which plays a major role in defending against pathogens in the intestinal tract. Without the J protein, individuals would have impaired immune responses in the gut, leading to frequent infections in the intestinal tract. Choices B, C, and D are incorrect because the J protein deficiency specifically affects the mucosal immune system in the intestinal tract, not the blood, liver, or pancreas.
A heart attack is
- A. damage to cardiac muscle
- B. Typically from a blocked coronary artery
- C. Death of brain tissue from blocked arteries in the head
- D. A & b
Correct Answer: D
Rationale: The correct answer is D because a heart attack, also known as a myocardial infarction, involves damage to the cardiac muscle due to a blocked coronary artery. Choice A is correct as it directly relates to the definition of a heart attack. Choice B is also correct as a blocked coronary artery is the main cause of decreased blood flow to the heart muscle leading to a heart attack. Choice C is incorrect as it refers to a stroke, which is the death of brain tissue due to blocked arteries in the head, not a heart attack. Therefore, A & B (choices A and B) are the correct options, making D the correct answer.
Which of the following is not a function of the immune system?
- A. Protecting the body from foreign substances
- B. Producing hormones
- C. Repairing damaged tissues
- D. All of the above are functions of the immune system
Correct Answer: B
Rationale: The correct answer is B: Producing hormones. The immune system's main functions are to protect the body from foreign substances and repair damaged tissues. Producing hormones is not a direct function of the immune system. Hormone production is primarily regulated by the endocrine system, not the immune system. Therefore, option B is not a function of the immune system. Options A and C are incorrect as protecting the body from foreign substances and repairing damaged tissues are essential roles of the immune system. Option D is incorrect because not all functions listed are actually performed by the immune system.