Nokea
What is the role of the spleen in the body?
- A. To produce bile
- B. To filter blood and remove old red blood cells
- C. To produce red blood cells
- D. To store fat
Correct Answer: B
Rationale: The correct answer is B. The spleen acts as a blood filter, removing old or damaged red blood cells. It also plays a role in immune responses, storing blood reserves, and helping to fight infection. The production of bile is primarily associated with the liver, not the spleen. While the bone marrow is responsible for red blood cell production, the spleen's main functions do not include this process. Storing fat is not a primary function of the spleen.
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Which property remains constant despite possible changes to the element?
- A. Atomic number
- B. Number of electrons
- C. Atomic mass
- D. Isotopic form
Correct Answer: A
Rationale: The correct answer is 'Atomic number' (A). The atomic number of an element remains constant as it defines the number of protons in the nucleus, which does not change despite various chemical reactions or physical processes affecting the element. The number of protons in the nucleus determines the identity of the element, and this fundamental property remains unchanged even if the element undergoes chemical reactions, forms ions, or changes its physical state. Choices B, C, and D are incorrect because the number of electrons (B) can change in chemical reactions, atomic mass (C) can vary with isotopes, and isotopic form (D) refers to variations in the number of neutrons in the nucleus, which can result in different isotopes of an element.
Which organ in the human body is responsible for filtering blood and producing urine?
- A. Liver
- B. Kidneys
- C. Pancreas
- D. Heart
Correct Answer: B
Rationale: The correct answer is B: Kidneys. The kidneys are vital organs in the human body responsible for filtering blood to remove waste products and excess substances, producing urine as a result. The liver plays a role in detoxification and metabolism. The pancreas is involved in digestion and blood sugar regulation. The heart pumps blood throughout the body but does not filter blood or produce urine.
What is the purpose of sodium bicarbonate when released into the lumen of the small intestine?
- A. It works to chemically digest fats in the chyme.
- B. It decreases the pH of the chyme to prevent harm to the intestine.
- C. It works to chemically digest proteins in the chyme.
- D. It increases the pH of the chyme to prevent harm to the intestine.
Correct Answer: D
Rationale: Sodium bicarbonate, when released into the lumen of the small intestine, functions to increase the pH of the acidic chyme coming from the stomach. This increase in pH helps neutralize the acidity of the chyme, creating a more optimal environment for the digestive enzymes in the small intestine to function properly. Maintaining a slightly basic pH in the small intestine is crucial for overall digestion and absorption of nutrients. Choices A, B, and C are incorrect. Sodium bicarbonate does not chemically digest fats or proteins in the chyme, and it does not decrease the pH of the chyme as it actually increases the pH to prevent harm to the intestine.
What are the three regions of the small intestine?
- A. Duodenum, ileum, jejunum
- B. Cecum, ileum, jejunum
- C. Duodenum, jejunum, ileum
- D. Duodenum, jejunum, colon
Correct Answer: C
Rationale: The correct answer is C: Duodenum, jejunum, ileum. The small intestine is divided into three regions: the duodenum, jejunum, and ileum. The duodenum is the initial segment where most chemical digestion takes place. The jejunum and ileum follow the duodenum and are primarily responsible for nutrient absorption. Choice A is incorrect because the order is incorrect. Choice B is incorrect because the cecum is part of the large intestine, not the small intestine. Choice D is incorrect because the colon is part of the large intestine, not the small intestine.
Most catalysts found in biological systems are which of the following?
- A. Special lipids called cofactors.
- B. Special proteins called enzymes.
- C. Special lipids called enzymes.
- D. Special proteins called cofactors.
Correct Answer: B
Rationale: Enzymes are special proteins that act as catalysts in biological systems. They accelerate chemical reactions by lowering the activation energy required for the reaction to occur. Enzymes play a critical role in the regulation of metabolic pathways and are essential for various biological processes. While some enzymes may require cofactors for activity, the enzymes themselves are the catalysts in biological systems. Therefore, choice B, special proteins called enzymes, is the most suitable answer. Choices A, C, and D are incorrect because enzymes, not lipids, are the primary catalysts in biological systems.