Practice TEAS Science Test

Correct Answer: C

Rationale: The correct answer is C: IgG. IgG is the only antibody that can cross the placenta due to its smaller size and ability to bind to neonatal Fc receptors. This allows for passive immunity to be transferred from mother to fetus. IgA is mainly found in mucosal secretions, IgD functions as a B cell receptor, and IgM is primarily involved in the primary immune response. IgG is the most abundant antibody in the circulation and plays a crucial role in protecting the fetus from infections.

Correct Answer: B

Rationale: The correct answer is B: Medulla oblongata. The medulla oblongata, located in the brainstem, controls essential functions like breathing and heart rate. It contains centers that regulate these automatic processes. The cerebrum (A) is responsible for higher brain functions, not controlling basic physiological functions. The thalamus (C) serves as a relay station for sensory information, not for regulating breathing and heart rate. The cerebellum (D) plays a role in coordination and movement, not in controlling vital functions like breathing and heart rate.

Correct Answer: D

Rationale: The correct answer is D: Type O. Type O blood lacks both A and B antigens, making it compatible with all blood types. As a result, it can be safely transfused to individuals with any blood type, earning it the title of the universal donor. Choice A (Type A) has A antigens, Choice B (Type B) has B antigens, and Choice C (Type AB) has both A and B antigens, making them not suitable for universal donation.

Correct Answer: B

Rationale: Iron is the correct answer because it is an essential component of hemoglobin, the protein in red blood cells responsible for transporting oxygen throughout the body. Without iron, the body cannot produce enough hemoglobin, leading to anemia. Calcium, potassium, and sodium do not play a direct role in hemoglobin synthesis. Calcium is important for bone health, potassium is crucial for nerve and muscle function, and sodium helps regulate fluid balance. Iron is the only element among the choices that is directly involved in hemoglobin formation.

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.