Nokea
Which of the following are not examples of a terminal electron acceptor in anaerobic respiration?
- A. nitrate
- B. hydrogen sulfate
- C. iron hydroxide
- D. Hâ‚‚
Correct Answer: D
Rationale: The correct answer is D: H₂. In anaerobic respiration, H₂ can act as a terminal electron acceptor, so it is not an incorrect example. Nitrate, hydrogen sulfate, and iron hydroxide are all examples of terminal electron acceptors in anaerobic respiration. H₂ is commonly used in microbial processes as an electron donor, not as a terminal electron acceptor. This is because H₂ is typically oxidized to produce energy, rather than accepting electrons.
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The membrane of gas vesicles is composed of:
- A. triglycerides
- B. phospholipids
- C. proteins
- D. lipopolysaccharide
Correct Answer: C
Rationale: The correct answer is C: proteins. Gas vesicles are gas-filled structures found in certain bacteria and archaea to provide buoyancy. The membrane of gas vesicles is predominantly composed of proteins that form a semi-permeable barrier to trap gas. Proteins are essential for the structure and function of gas vesicles. Triglycerides (A) are not typically found in membrane structures, phospholipids (B) are more common in cell membranes, and lipopolysaccharides (D) are typically found in the outer membrane of Gram-negative bacteria, not in gas vesicle membranes.
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.
Which class of biological molecules can be bound by an immunoglobulin?
- A. Proteins
- B. Carbohydrates
- C. Lipids
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D, "All of the above." Immunoglobulins are antibodies produced by the immune system to recognize and bind to foreign molecules called antigens. These antigens can be proteins (choice A), carbohydrates (choice B), or lipids (choice C). Therefore, immunoglobulins can bind to all classes of biological molecules. Choices A, B, and C are incorrect as they each represent individual classes of molecules that can be targeted by immunoglobulins, but the correct answer encompasses all of them.
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.