TEAS 7 practice test science

Correct Answer: C

Rationale: The correct answer is C, Neutron. Neutrons are subatomic particles found in the nucleus of an atom that have no charge. They have a mass of approximately 1 atomic mass unit (amu). The number of neutrons in an atom's nucleus contributes to the mass number of the atom, which is the total number of protons and neutrons in the nucleus. Choice A, Electron, is incorrect as electrons are negatively charged particles found outside the nucleus. Choice B, Proton, is incorrect as protons are positively charged particles found in the nucleus. Choice D, Positron, is incorrect as positrons are positively charged antiparticles of electrons and are not typically found in the nucleus of an atom.

Correct Answer: A

Rationale: The endoplasmic reticulum (ER) is a network of membranes within the cell that plays a crucial role in protein and lipid synthesis. It consists of two types: rough ER, which is studded with ribosomes and involved in protein synthesis, and smooth ER, which is involved in lipid synthesis and detoxification. The ER's main function is to synthesize proteins and lipids, not just package and transport them. While the ER is involved in transporting these synthesized proteins and lipids to other parts of the cell or outside the cell, its primary role is in their synthesis. Breaking down macromolecules is primarily the function of lysosomes, which are membrane-bound organelles containing enzymes for digestion. Storing genetic material is the function of the nucleus, which houses the cell's DNA. The ER is not involved in storing genetic material.

Correct Answer: B

Rationale: Mass is the quantity of matter in an object and is commonly measured in kilograms or grams. It is a fundamental property of matter and remains constant regardless of the object's location. Weight, in contrast, refers to the force of gravity acting on an object and is measured in newtons. Volume represents the amount of space an object occupies and is typically measured in cubic units like cubic meters or cubic centimeters. Density, on the other hand, is the mass of an object per unit volume, and its unit is, for example, kilograms per cubic meter. Therefore, the correct answer is 'Mass' as it specifically describes the quantity of matter in an object, regardless of the gravitational pull on it. 'Weight,' 'Volume,' and 'Density' do not directly represent the quantity of matter in an object but rather different properties related to it.

Correct Answer: C

Rationale: The correct answer is C, Neutron. Neutrons are subatomic particles found in the nucleus of an atom that have no charge. They have a mass of approximately 1 atomic mass unit (amu). The number of neutrons in an atom's nucleus contributes to the mass number of the atom, which is the total number of protons and neutrons in the nucleus. Choice A, Electron, is incorrect as electrons are negatively charged particles found outside the nucleus. Choice B, Proton, is incorrect as protons are positively charged particles found in the nucleus. Choice D, Positron, is incorrect as positrons are positively charged antiparticles of electrons and are not typically found in the nucleus of an atom.

Correct Answer: B

Rationale: Covalent bonds are formed by the sharing of electrons between atoms, leading to the formation of molecules with directional bonding. This means that the atoms are held together in a specific orientation. Covalent compounds generally exhibit low melting and boiling points compared to ionic compounds due to the weaker intermolecular forces present in covalent compounds. Furthermore, covalent compounds do not conduct electricity in the solid state because the electrons are localized between the atoms and are not free to move and carry charge. Hence, high melting and boiling points are not characteristic of covalent bonds. The correct answer is 'B' because high melting and boiling points are typically associated with ionic compounds due to their strong electrostatic interactions, while covalent compounds have lower melting and boiling points. Choices A, C, and D are all characteristics of covalent bonds, making them incorrect answers for this question.