Nokea
Which of the following cell types produce and release antibodies?
- A. Helper T cells
- B. Cytotoxic T cells
- C. Plasma B cells
- D. Natural Killer cells
Correct Answer: C
Rationale: Plasma B cells are specialized cells that are responsible for producing and releasing antibodies. These antibodies play a vital role in the immune response by recognizing and neutralizing harmful pathogens like bacteria and viruses. Helper T cells aid in activating B cells and other immune cells, cytotoxic T cells are involved in eliminating infected or abnormal cells, and natural killer cells are part of the innate immune system, targeting virus-infected and tumor cells.
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In light of the recent discovery that worm infection can relieve certain autoimmune disorders, how should the hypothesis be modified regarding parasitic infections?
- A. Worm infection reduces certain autoimmune disorders.
- B. Worm infestation is a cause of some autoimmune disorders.
- C. Worm infestation prevents immune malfunction.
- D. Worm infections exacerbate immune reactions.
Correct Answer: A
Rationale: The recent discovery that worm infection can relieve certain autoimmune disorders suggests a need to modify the hypothesis. Instead of viewing all parasitic infections as harmful, the new information indicates that worm infection can actually reduce certain autoimmune disorders. This challenges the previous belief and highlights a potential therapeutic benefit. Choices B, C, and D do not reflect the new understanding and should be eliminated. Therefore, option A, 'Worm infection reduces certain autoimmune disorders,' aligns with the updated hypothesis based on the recent discovery and is the correct answer.
Which one of the following structures drains oxygen-depleted blood from the kidneys?
- A. Ureter
- B. Renal artery
- C. Urethra
- D. Renal vein
Correct Answer: D
Rationale: The correct answer is D, Renal vein. The renal vein is responsible for draining oxygen-depleted blood from the kidneys back to the heart for reoxygenation. The ureter carries urine from the kidneys to the bladder, the renal artery supplies oxygenated blood to the kidneys, and the urethra is the tube that carries urine from the bladder out of the body. Therefore, in the context of blood drainage from the kidneys, the renal vein is the correct choice.
htmlspecialchars(The mitochondrial inner membrane carries out the same functions in cellular respiration as the ......... membrane of chloroplasts in photosynthesis. Which of the following correctly completes the sentence above?)
- A. htmlspecialchars(Epithelial)
- B. htmlspecialchars(Nuclear)
- C. htmlspecialchars(Thylakoid)
- D. htmlspecialchars(Tonoplast)
Correct Answer: htmlspecialchars(C)
Rationale: htmlspecialchars(The correct answer is C - Thylakoid. The inner membrane of mitochondria is where cellular respiration occurs, just as the thylakoid membrane in chloroplasts is where photosynthesis takes place. These membranes are essential for energy production in their respective processes. Understanding the role of these membranes is crucial in comprehending how cells generate energy through cellular respiration and photosynthesis.)
Where do both digestion and absorption occur in the digestive system?
- A. Stomach
- B. Esophagus
- C. Gallbladder
- D. Small intestine
Correct Answer: D
Rationale: Both digestion and absorption take place in the small intestine. The small intestine is a crucial organ where the breakdown of food into smaller molecules, digestion, occurs with the help of enzymes. This process is essential for the absorption of nutrients, where the smaller molecules are taken up by the bloodstream for distribution throughout the body. While the stomach aids in digestion through the action of gastric juices, the esophagus serves as a tube for food passage, and the gallbladder stores bile produced by the liver to aid in fat digestion. However, neither digestion nor absorption occurs in the stomach, esophagus, or gallbladder, making the small intestine the correct answer for both processes.
Why do chloride ions have a negative charge?
- A. It lost a proton.
- B. It gained a proton.
- C. It gained an electron.
- D. It lost an electron.
Correct Answer: C
Rationale: Chloride ions (Cl-) have a negative charge because they gained an electron. When an atom gains an electron, it increases the number of negative charges relative to positive charges, resulting in a net negative charge, as seen in chloride ions. In the case of chloride ions, a chlorine atom gains an extra electron to achieve a stable electron configuration, turning it into a chloride ion with a negative charge.