TEAS 7 practice test free science

Correct Answer: B

Rationale: Passive transport refers to the movement of molecules across a cell membrane without the input of energy. Diffusion of small molecules across a concentration gradient is a classic example of passive transport, as it occurs spontaneously from an area of high concentration to an area of low concentration. Active transport (option A) requires energy input in the form of ATP to move substances against their concentration gradient. Movement of large molecules using vesicles (option C) involves processes like endocytosis and exocytosis that require energy in the form of ATP. Endocytosis of particles into the cell (option D) is an active process that requires energy expenditure by the cell to engulf and internalize extracellular substances.

Correct Answer: C

Rationale: The epiglottis plays a crucial role during swallowing by covering the trachea to prevent food or liquid from entering the airway, which could lead to aspiration. By acting as a lid over the trachea, it ensures that food passes down the esophagus to the stomach, preventing it from entering the lungs. Choice A is incorrect as the swallowing reflex is a coordinated muscular action involving the tongue and throat muscles. Choice B is incorrect as grinding food into smaller pieces is primarily the function of the teeth and the initial stages of digestion. Choice D is incorrect as the storage of saliva for lubrication is not a function of the epiglottis, but rather involves salivary glands.

Correct Answer: D

Rationale: The mitral valve, also known as the bicuspid valve, is located between the left atrium and the left ventricle of the heart. Its primary function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. The aortic valve (A) prevents the backflow of blood from the aorta into the left ventricle, the pulmonary valve (B) prevents the backflow of blood from the pulmonary artery into the right ventricle, and the tricuspid valve (C) prevents the backflow of blood from the right ventricle into the right atrium. Understanding the functions of these heart valves is crucial in maintaining proper blood flow through the heart and preventing regurgitation of blood into the wrong chambers.

Correct Answer: B

Rationale: - In the reaction, potassium ions (K+) and chloride ions (Cl-) are present on both sides of the equation. They are not involved in the formation of the products and remain unchanged. - Lead ions (Pb2+) and nitrate ions (NO3-) are involved in the formation of the products potassium nitrate (KNO3) and lead(II) chloride (PbCl2). - Therefore, the spectator ions in this reaction are K+ and Cl-.

Correct Answer: A

Rationale: Sodium hydroxide (NaOH) is a strong base commonly used in cleaning products due to its effectiveness in breaking down grease and fats. It is known for its corrosive properties and is commonly found in drain cleaners and oven cleaners. While ammonium hydroxide, calcium hydroxide, and potassium hydroxide are also bases, they are not as strong as sodium hydroxide and are not as commonly used in cleaning products. Ammonium hydroxide is more commonly found in household cleaning products for its disinfectant properties, calcium hydroxide is used in agriculture and construction, and potassium hydroxide is often used in industries like soap manufacturing and biodiesel production.