ATI TEAS 7
ATI TEAS 7 Version 1 Science Questions
Extract:
Question 1 of 5
What summarizes a change that occurs as solids transition into liquids?
Correct Answer: A
Rationale: The correct answer is A. When solids transition into liquids, particles become less ordered. In a solid state, particles are arranged in a fixed, orderly pattern due to strong intermolecular forces. As the solid transitions into a liquid, these forces weaken, allowing the particles more freedom of movement. Consequently, the particles become less ordered in a liquid compared to a solid, where they have more mobility and are not bound in a fixed structure.
Extract:
Question 2 of 5
What is the primary outcome of using a catalyst in a chemical reaction?
Correct Answer: C
Rationale: The primary outcome of using a catalyst in a chemical reaction is to accelerate the reaction and complete it in a shorter timeframe. A catalyst functions by lowering the activation energy required for the reaction to occur, thereby speeding up the process without altering the amount of heat energy released, the yield of the product, or the nature of the final product. This acceleration makes the reaction more efficient by facilitating the conversion of reactants to products in a more rapid manner.
Question 3 of 5
What is the approximate threshold value for mammalian neurons?
Correct Answer: B
Rationale: The approximate threshold value for mammalian neurons is around -55 mV. At this membrane potential, the neuron becomes more excitable and is more likely to generate an action potential. If the membrane potential reaches this level or depolarizes beyond it, it triggers the opening of voltage-gated ion channels, leading to the initiation of an action potential. Values below this threshold are considered subthreshold and do not usually result in action potential generation. Understanding the threshold potential is crucial in assessing the excitability and firing properties of neurons, as it represents the critical point at which the neuron transitions from a resting state to an active state, enabling the transmission of electrical signals.
Question 4 of 5
Which of the following ions binds to the troponin complex, initiating muscle contraction?
Correct Answer: D
Rationale: The correct answer is calcium (D). Calcium ions bind to the troponin complex, initiating muscle contraction. When calcium binds to troponin, it causes a conformational change in the troponin-tropomyosin complex, exposing the binding sites on actin for myosin. This interaction allows muscle contraction by facilitating the sliding of actin and myosin filaments past each other, leading to muscle contraction.
Question 5 of 5
Lithium has an atomic number of 3 and a mass number of 7. What is the number of protons in a lithium atom?
Correct Answer: D
Rationale: The number of protons in an atom is equal to its atomic number. In this case, lithium has an atomic number of 3, so it contains 3 protons. The mass number (7) includes both protons and neutrons, with the difference between the mass number and atomic number representing the number of neutrons. Therefore, the correct answer is 3 protons in a lithium atom.