TEAS 7 practice test science

Correct Answer: C

Rationale: HIV targets and destroys Helper T cells, which are vital for coordinating the immune response against infections. The destruction of Helper T cells weakens the immune system, leading to acquired immunodeficiency syndrome (AIDS). Neutrophils (Choice A) are primarily involved in acute inflammatory responses and fighting bacterial infections. Macrophages (Choice B) play a role in phagocytosis and antigen presentation but are not the primary target of HIV. Memory B cells (Choice D) are responsible for mounting a quicker and more robust antibody response upon re-exposure to a pathogen, but they are not the main target of HIV infection.

Correct Answer: D

Rationale: Vitamin B12 requires intrinsic factor, a glycoprotein secreted by the parietal cells of the stomach, for proper absorption in the small intestine. Intrinsic factor binds to vitamin B12 and facilitates its absorption in the ileum. Deficiency in intrinsic factor can lead to pernicious anemia, a condition characterized by a lack of vitamin B12 absorption. Options A, B, and C are incorrect. Vitamin A is absorbed in the small intestine with the help of bile salts; Vitamin C is absorbed in the small intestine via active transport; Vitamin D is absorbed in the small intestine through a process involving bile salts and micelles. It is essential for students to understand this relationship as it highlights the importance of intrinsic factor in the absorption of specific vitamins and the consequences of its deficiency.

Correct Answer: B

Rationale: When a person throws a ball horizontally, the initial force that propels the ball forward is the force of throwing (A). However, the force that changes the direction of the ball's motion is the gravitational force (B). Gravitational force acts vertically downward, causing the ball to follow a curved path. Air resistance (C) and normal force from the ground (D) do not directly change the direction of the ball's motion in this scenario.

Correct Answer: C

Rationale: The main target organ for insulin is muscles. Insulin plays a crucial role in regulating glucose metabolism by promoting the uptake of glucose into muscle cells. This glucose can then be utilized for energy production or stored for later use. Therefore, muscles are the primary site where insulin exerts its effects on glucose uptake and utilization. The liver primarily responds to insulin by regulating glucose storage and release, but the main target for insulin-mediated glucose uptake is muscles. Kidneys are not a target organ for insulin action in glucose metabolism. The brain does not heavily rely on insulin for glucose uptake as it primarily uses glucose independently of insulin for energy production.

Correct Answer: A

Rationale: The endoplasmic reticulum (ER) is a network of membranes within the cell that plays a crucial role in protein and lipid synthesis. It consists of two types: rough ER, which is studded with ribosomes and involved in protein synthesis, and smooth ER, which is involved in lipid synthesis and detoxification. The ER's main function is to synthesize proteins and lipids, not just package and transport them. While the ER is involved in transporting these synthesized proteins and lipids to other parts of the cell or outside the cell, its primary role is in their synthesis. Breaking down macromolecules is primarily the function of lysosomes, which are membrane-bound organelles containing enzymes for digestion. Storing genetic material is the function of the nucleus, which houses the cell's DNA. The ER is not involved in storing genetic material.