which of the following distinguishes the isotopes of an element

ATI TEAS 7

TEAS 7 Science Practice Test

1. Which of the following distinguishes the isotopes of an element?

A. Isotopes are atoms of the same element that have different ionic charges.
B. Isotopes are atoms of elements within the same group on the periodic table.
C. Isotopes are atoms of the same element that have different numbers of neutrons.
D. Isotopes are atoms of the same element with different electron configurations.

Correct answer: C

Rationale: Isotopes are defined as atoms of the same element that have the same number of protons in their nucleus but different numbers of neutrons. This leads to variations in atomic mass for isotopes of an element. The different number of neutrons in isotopes results in differences in their atomic mass and properties while still belonging to the same element. Choice A is incorrect because isotopes do not have different ionic charges, they have the same chemical properties. Choice B is incorrect because isotopes are not atoms of elements within the same group on the periodic table; they are variants of the same element. Choice D is incorrect because isotopes of an element have the same electron configuration, differing only in the number of neutrons in the nucleus.

2. What is the main difference between a nuclear reactor and a nuclear bomb?

A. Reactors use enriched uranium, while bombs use natural uranium.
B. Reactors have controlled chain reactions, while bombs have uncontrolled chain reactions.
C. Reactors generate electricity, while bombs cause explosions.
D. Reactors use moderators, while bombs don't.

Correct answer: B

Rationale: The main difference between a nuclear reactor and a nuclear bomb is that reactors have controlled chain reactions, while bombs have uncontrolled chain reactions. Nuclear reactors are designed to sustain a controlled nuclear reaction to generate electricity. In contrast, nuclear bombs are designed to release a massive amount of energy in an uncontrolled chain reaction, resulting in an explosion. Choice A is incorrect because both reactors and bombs can use enriched uranium. Choice C is incorrect as nuclear reactors also generate electricity, not just bombs. Choice D is incorrect because both reactors and bombs may or may not use moderators, but the key distinction lies in the control of the chain reaction.

3. What is the main function of vacuoles in plant cells?

A. To provide structural support for the cell
B. To transport substances in and out of the cell
C. To synthesize proteins and lipids
D. To store water, enzymes, and waste products

Correct answer: D

Rationale: Vacuoles in plant cells primarily function as storage organelles. They store water, enzymes, pigments, and waste products, helping to maintain turgor pressure within the cell. This turgor pressure provides structural support for the plant cell. While vacuoles can also participate in transporting substances within the cell, their main role is storage. The synthesis of proteins and lipids is mainly handled by other organelles such as the endoplasmic reticulum and Golgi apparatus. Choice A is incorrect because while vacuoles indirectly contribute to structural support by maintaining turgor pressure, their primary function is storage. Choice B is incorrect as vacuoles are not primarily responsible for transporting substances in and out of the cell. Choice C is incorrect as vacuoles do not synthesize proteins and lipids; this function is carried out by other organelles.

4. What is the term for the process of breaking a large molecule into smaller fragments by applying heat?

A. Polymerization
B. Hydrogenation
C. Isomerization
D. Pyrolysis

Correct answer: D

Rationale: Pyrolysis is the correct answer. It is the process of breaking down large molecules into smaller fragments by applying heat in the absence of oxygen. This results in the decomposition of molecules into simpler compounds. Polymerization, the process of synthesizing large molecules from smaller units, is incorrect as it is the opposite process. Hydrogenation involves adding hydrogen atoms to a compound, usually with a catalyst, which is not related to breaking down large molecules. Isomerization refers to rearranging atoms within a molecule to form isomeric compounds with the same molecular formula but different structural arrangements, which is also unrelated to the process described in the question.

5. Dense irregular connective tissue, found in tendons and ligaments, provides:

A. Flexibility
B. Lubrication
C. Insulation
D. Tensile strength

Correct answer: D

Rationale: Dense irregular connective tissue, found in tendons and ligaments, provides tensile strength. Tendons and ligaments need to withstand tension and forces acting upon them, and the dense irregular connective tissue helps provide this strength and support. Choice A, flexibility, is incorrect because tendons and ligaments primarily provide support and stability rather than flexibility. Choice B, lubrication, is not the main function of dense irregular connective tissue in tendons and ligaments. Choice C, insulation, is also incorrect as this tissue type is not primarily involved in providing insulation.