TEAS Practice Test Science

Correct Answer: B

Rationale: The pancreas produces insulin to lower blood sugar levels and glucagon to raise them. Insulin helps cells take in glucose for energy or storage. Glucagon signals the liver to release stored glucose. Storing glucose (option C) is not the primary function of the pancreas. Adrenaline (option D) is produced by the adrenal glands, not the pancreas.

Correct Answer: B

Rationale: The correct answer is B: Meiosis Prophase I. Crossing over occurs during Prophase I of meiosis, specifically during the substage called pachytene. This is when homologous chromosomes pair up and exchange genetic material. This process creates genetic diversity among offspring. Choice A, Mitosis Prophase, is incorrect because crossing over does not occur during mitosis, as homologous chromosomes do not pair up in mitosis. Choice C, Meiosis Prophase II, is incorrect because crossing over only occurs during Prophase I, not Prophase II. Choice D, Interphase, is incorrect because crossing over does not occur during interphase, as it is a phase where the cell prepares for division and DNA replication occurs.

Correct Answer: B

Rationale: The correct answer is B: Larynx. The larynx houses the vocal cords, which vibrate to produce sound for voice production. The pharynx is involved in swallowing, the trachea is responsible for air passage to the lungs, and the bronchi are the airways that branch off from the trachea into the lungs. The larynx specifically contains the vocal cords, making it the structure responsible for voice production.

Correct Answer: C

Rationale: The correct answer is C: Natural Killer cells. Natural Killer cells are part of the innate immune response as they can recognize and eliminate infected or abnormal cells without prior exposure. B-cells and cytotoxic T-cells are part of the adaptive immune response, requiring specific antigens to respond. Antigen-Presenting Cells play a crucial role in initiating the adaptive immune response by presenting antigens to T-cells. Therefore, Natural Killer cells are the only cells listed that belong to the innate immune response.

Correct Answer: A

Rationale: The correct answer is A: Helicase. Helicase is responsible for unwinding the double-stranded DNA during replication by breaking the hydrogen bonds between the base pairs. This allows the DNA strands to separate and serve as templates for the synthesis of new DNA strands by DNA polymerase. Ligase is responsible for joining the DNA fragments together, nuclease is involved in DNA repair by cutting out damaged DNA, and polymerase is responsible for synthesizing new DNA strands based on the template strands. Therefore, only helicase directly unwinds the double-stranded DNA during replication.