Practice Science TEAS Test

Correct Answer: B

Rationale: The correct answer is B: Pineal gland. The pineal gland secretes the hormone melatonin, which plays a crucial role in regulating the body's circadian rhythm. Melatonin helps control the sleep-wake cycle, making it responsible for maintaining the body's internal clock. The other choices are incorrect because the thyroid gland regulates metabolism (A), the pancreas regulates blood sugar levels (C), and the hypothalamus controls various bodily functions but is not directly responsible for maintaining the circadian rhythm (D).

Correct Answer: B

Rationale: The correct answer is B: Serotonin. Serotonin is associated with feelings of happiness and well-being because it helps regulate mood, emotions, and sleep. Low levels of serotonin have been linked to depression and anxiety. Dopamine (A) is associated with pleasure and reward, GABA (C) is an inhibitory neurotransmitter that helps reduce anxiety, and Acetylcholine (D) is involved in muscle movement and memory. Serotonin is the most relevant neurotransmitter for happiness and well-being due to its specific role in regulating mood and emotions.

Correct Answer: D

Rationale: The correct answer is D because the liver filters and detoxifies digestion byproducts. It processes nutrients from food, removes toxins, and metabolizes drugs. Choice A is incorrect because the liver produces bile, not just for digestion but also for waste elimination. Choice B is incorrect as the gallbladder stores bile. Choice C is incorrect as the liver converts waste ammonia into urea as part of the metabolic process, not specifically related to digestion.

Correct Answer: B

Rationale: The correct answer is B: Glycolysis. Glycolysis is the process where glucose is broken down into pyruvic acid through a series of enzymatic reactions in the cytoplasm. This process involves multiple steps including phosphorylation, isomerization, cleavage, and oxidation. Glycogenesis (choice A) is the synthesis of glycogen from glucose, not the breakdown. Glycogenolysis (choice C) is the breakdown of glycogen into glucose, not the conversion of glucose to pyruvic acid. Gluconeogenesis (choice D) is the synthesis of glucose from non-carbohydrate precursors, not the conversion of glucose to pyruvic acid.

Correct Answer: C

Rationale: The correct answer is C: Iron (II). In heme, the central cation is Iron (II) because it forms a coordination complex with the porphyrin ring. Iron (II) has a +2 charge, allowing it to bind to the nitrogen atoms in the porphyrin ring. This binding is crucial for the proper functioning of heme in carrying oxygen in hemoglobin. Choice A (Cr III) is incorrect because chromium (III) does not typically bind to porphyrin rings in heme. Choice B (Cu II) is incorrect because copper (II) is not commonly found at the center of heme. Choice D (Iron III) is incorrect because in heme, iron is usually in the +2 oxidation state to efficiently bind and release oxygen. Iron (III) is not as effective in this role.