ATI TEAS Science Practice Test

Correct Answer: B

Rationale: Nuclei are structures that are unique to eukaryotic cells. Prokaryotic cells lack a defined nucleus, and their genetic material floats freely in the cytoplasm. Eukaryotic cells have nuclei that house the genetic material in the form of chromosomes, separated from the cytoplasm by a nuclear membrane. This distinct organelle is a key feature that sets eukaryotic cells apart from prokaryotic cells. Cell walls (Choice A) are found in plant cells, fungi, and some prokaryotes but are not unique to eukaryotic cells. Cell membranes (Choice C) are present in both prokaryotic and eukaryotic cells, serving as a barrier that encloses the cell contents. Vacuoles (Choice D) are membrane-bound organelles found in both plant and animal cells, making them not unique to eukaryotic cells.

Correct Answer: C

Rationale: The parasympathetic nervous system is often referred to as the 'rest and digest' system because it promotes activities that occur when the body is at rest, such as digestion. This system helps stimulate digestion by increasing gastrointestinal motility, secretion of digestive enzymes, and blood flow to the digestive organs. Choices A, B, and D are incorrect because they are functions associated with the sympathetic nervous system, which is responsible for the 'fight-or-flight' response, increasing heart rate, and dilating bronchioles to facilitate more oxygen intake during stressful situations.

Correct Answer: C

Rationale: The correct answer is C: 'Bonding electrons are shared between two or more atoms.' This statement is unique to covalent bonds. In covalent bonds, atoms share electrons to achieve a stable electron configuration, which leads to the formation of a bond. This sharing of electrons is a fundamental characteristic of covalent bonds and distinguishes them from other types of chemical bonds, such as ionic bonds, where electrons are transferred rather than shared. Choices A, B, and D do not represent unique characteristics of covalent bonds. Choice A describes some common elements involved in covalent bonds, choice B refers to the concept of dipoles, which can also exist in other types of bonds, and choice D describes a property of molecules (crystalline solid structure) that is not exclusive to covalent bonds.

Correct Answer: B

Rationale: Accuracy refers to how close a measurement is to the true or accepted value, while precision refers to how close individual measurements are to each other. If the measurements are accurate but not precise, it means they consistently hit the target value but may vary in terms of how closely grouped they are. Choice B, 'They are accurate but not precise,' correctly describes the scenario where the measurements are on target but not consistently close to each other. Choice A is incorrect because it implies both accuracy and precision, which is not the case here. Choice C is incorrect because it suggests precision without accuracy, while choice D is incorrect as it indicates neither accuracy nor precision, which is not a typical scenario for measurements.

Correct Answer: D

Rationale: Human cells typically contain genes that code for proteins necessary for the cell's functions. DNA that codes for proteins the cell doesn't use would be an inefficient use of the cell's resources. Therefore, it is less likely to be found in a human cell's genes. Options A, B, and C are more commonly associated with genes found in human cells. Choice A refers to the genetic information needed for protein synthesis, while choice B involves traits that can be present in the gene pool. Mutated DNA (choice C) can also be found in human cells as a result of genetic alterations. However, DNA that codes for proteins not utilized by the cell would be redundant and not typically retained in the genome.