ATI TEAS 7
Mometrix TEAS 7 science practice test
1. When is a solution formed?
- A. One substance dissolves in another
- B. Two or more substances react chemically
- C. A solid changes to a liquid
- D. None of the above
Correct answer: A
Rationale: A solution is formed when one substance dissolves in another. This process creates a homogeneous mixture where the solute is dispersed in the solvent, resulting in a uniform composition throughout the mixture. Choice B is incorrect because chemical reactions involve the transformation of substances into new compounds, not the formation of solutions. Choice C is incorrect as it describes a physical change from a solid to a liquid, not the formation of a solution. Choice D is incorrect as one substance dissolving in another is the defining characteristic of a solution.
2. How does AIDS impair the immune system?
- A. AIDS targets and destroys Helper T-Cells, preventing the activation of Cytotoxic T-Cells or B-Cells.
- B. IgE stimulates mast cells to release excessive histamine.
- C. IgE inhibits mast cells from releasing sufficient histamine.
- D. Helper T-Cells deceive the body into attacking itself.
Correct answer: A
Rationale: AIDS targets and destroys Helper T-Cells, which play a crucial role in coordinating the immune response. By affecting these cells, AIDS prevents the activation of other important immune cells like Cytotoxic T-Cells or B-Cells. This disruption in the immune system's communication and response mechanisms leads to immune system failure and increased vulnerability to infections. Choices B and C are incorrect because they refer to the role of IgE in allergic reactions, which is not directly related to how AIDS impairs the immune system. Choice D is also incorrect as Helper T-Cells being destroyed in AIDS is not about deceiving the body into attacking itself, but rather the direct impact on immune system function.
3. What is the functional group present in aldehydes?
- A. Hydroxyl
- B. Carbonyl
- C. Ester
- D. Amine
Correct answer: B
Rationale: The correct answer is B: Carbonyl. Aldehydes contain the functional group -CHO, which is a carbonyl group where a carbon atom is double-bonded to an oxygen atom and single-bonded to a hydrogen atom. This distinguishes aldehydes from other functional groups. Choice A, Hydroxyl (-OH), is not characteristic of aldehydes as it is found in alcohols. Choice C, Ester (-COOR), and choice D, Amine (-NH2), represent different functional groups not typically found in aldehydes. Therefore, the correct functional group present in aldehydes is the carbonyl group.
4. What is the process of converting light energy into chemical energy called?
- A. Respiration
- B. Fermentation
- C. Photosynthesis
- D. Hydrolysis
Correct answer: C
Rationale: - Respiration (Option A) is the process by which cells break down glucose to release energy. - Fermentation (Option B) is an anaerobic process that also involves the breakdown of glucose to release energy. - Hydrolysis (Option D) is a chemical process that involves the breakdown of molecules by adding water. Photosynthesis (Option C) is the process by which green plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose. During photosynthesis, plants use sunlight, carbon dioxide, and water to produce glucose and oxygen. This process is essential for the survival of plants and ultimately sustains life on Earth by providing oxygen for other organisms to breathe and serving as a source of energy in the food chain.
5. What is the term for a solution that contains less solute than the maximum amount it could dissolve at a specific temperature and pressure?
- A. Saturated solution
- B. Unsaturated solution
- C. Supersaturated solution
- D. Concentrated solution
Correct answer: B
Rationale: An unsaturated solution is a solution that contains less solute than the maximum amount it could dissolve at a specific temperature and pressure. In an unsaturated solution, more solute can still be added and dissolved in the solvent. Choice A, a saturated solution, refers to a solution in which the maximum amount of solute has been dissolved at a specific temperature and pressure, leading to equilibrium. Choice C, a supersaturated solution, contains more solute than it can normally hold at a specific temperature and pressure, achieved through special conditions followed by rapid cooling or evaporation. Choice D, a concentrated solution, refers to a solution with a high amount of solute compared to the amount of solvent, regardless of reaching the saturation point.
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