Practice TEAS Science Test

Correct Answer: C

Rationale: The correct answer is C because an allergic reaction is triggered by the release of histamine and other inflammatory molecules from mast cells, which are stimulated by Immunoglobulin E. This process leads to symptoms such as hives, itching, swelling, and difficulty breathing. Other choices are incorrect because: A: While integumentary and respiratory systems are involved in allergic reactions, they are not overactive systems but rather respond to the allergen. B: B-cells produce antibodies, not immunoglobulins directly related to allergic reactions. D: Histamine is involved in allergic reactions, but keratin and collagen are not typically associated with allergic responses.

Correct Answer: D

Rationale: The correct answer is D: Pia mater. Pia mater is the innermost meningeal layer that is a thin membrane containing nerves and blood vessels. It directly covers the brain and spinal cord, supplying nourishment to the underlying cells. Arachnoid mater (A) is the middle meningeal layer that does not contain nerves and blood vessels. Dura mater (B) is the tough outermost layer that does not supply nourishment. Periosteum (C) is a connective tissue covering bones, not the meninges.

Correct Answer: A

Rationale: The correct answer is A: Ectoderm. During embryonic development, the nervous system originates from the ectoderm layer. The neural plate forms from the ectoderm, which further develops into the neural tube and neural crest cells, giving rise to the brain, spinal cord, and peripheral nervous system. The other choices, B: Endoderm, C: Gastroderm, and D: Mesoderm, do not give rise to the nervous system. Endoderm forms the innermost layer of organs like the gut, Gastroderm is not a recognized germ layer, and Mesoderm gives rise to structures like muscles, bones, and connective tissues, not the nervous system.

Correct Answer: B

Rationale: The correct answer is B: Alveoli. Alveoli are tiny air sacs in the lungs where gas exchange occurs. Oxygen from the air we breathe passes into the blood vessels surrounding the alveoli, while carbon dioxide from the blood moves into the alveoli to be exhaled. The other choices are incorrect because: A: Trachea is the windpipe that carries air to and from the lungs, but gas exchange does not occur there. C: Bronchioles are small air passages that branch off the bronchi, leading air to the alveoli, but they are not the site of gas exchange. D: Diaphragm is a muscle that helps with breathing by expanding and contracting the chest cavity, but it is not directly involved in gas exchange.

Correct Answer: B

Rationale: The correct answer is B (2 ATP molecules produced per FADH2 molecule) in aerobic respiration. FADH2 enters the electron transport chain at a later stage compared to NADH, leading to the production of 2 ATP through oxidative phosphorylation. FADH2 donates electrons to Complex II, bypassing Complex I, resulting in a lower energy yield compared to NADH which donates electrons to Complex I. Choice A (1 ATP) is incorrect as FADH2 produces more ATP than that. Choice C (3 ATP) is incorrect as FADH2 produces 2 ATP, not 3. Choice D (4 ATP) is incorrect as FADH2 produces 2 ATP, not 4.