ATI TEAS Practice Science Test

Correct Answer: C

Rationale: The correct answer is C: Paracrine. This is because somatostatin is a chemical signal that acts locally on neighboring cells within the pancreas to inhibit insulin secretion. Paracrine signals are released by one cell and act on nearby cells of the same tissue. Autocrine signals act on the same cell that produced them, which is not the case here. Neuromodulators modulate the activity of neurons, not endocrine cells like in this scenario. Pheromones are chemical signals that are used for communication between individuals of the same species, not within the same organism like in this case.

Correct Answer: A

Rationale: The correct answer is A: Flagellum. Cells rely on flagella for movement because flagella are whip-like structures that enable cells to propel themselves through fluid environments. Flagella are composed of microtubules, which provide structural support and enable movement through their bending and contracting motion. Microtubules alone (B) do not facilitate movement; they serve as a scaffold within cells. Pili (C) are short, hair-like structures used for attachment rather than movement. Vesicles (D) are membrane-bound sacs involved in transportation within cells, not in cell movement. Therefore, flagellum is the most suitable structure for cellular movement.

Correct Answer: B

Rationale: The correct answer is B because endocrine glands release hormones directly into the bloodstream. Therefore, an extensive network of blood vessels is necessary to facilitate the direct release of hormones into the blood for systemic circulation. The other choices are incorrect because: A: Filtering waste from the blood is the function of the kidneys, not the endocrine glands. C: Blood does not "empty" into the endocrine system; rather, hormones are released into the bloodstream. D: Endocrine glands do not filter waste; instead, they produce and release hormones into the blood for various physiological functions.

Correct Answer: A

Rationale: During Prophase I of meiosis, chiasmata structures form as homologous chromosomes exchange genetic material through crossing over. This occurs after homologous chromosomes pair up during synapsis. Chiasmata play a crucial role in genetic diversity. In contrast, Prophase II is focused on preparing the cells for division, and chiasmata formation does not occur during this phase. Metaphase I is characterized by the alignment of homologous chromosomes at the metaphase plate, while Metaphase II involves the alignment of sister chromatids. Therefore, the correct answer is A: Prophase I, as it is the specific phase where chiasmata formation takes place.

Correct Answer: D

Rationale: The impaired posterior pituitary gland leads to decreased production of antidiuretic hormone (ADH), resulting in the inability to concentrate urine. This causes the patient to excrete large volumes of dilute urine. Thirst (choice A) is a symptom of diabetes insipidus, a condition related to ADH deficiency. Tiredness (choice B) and weight gain (choice C) are not directly associated with impaired posterior pituitary function. Thus, choice D, concentrated urine, is the correct symptom related to kidney function in this scenario.