Biology Practice Test

Correct Answer: D

Rationale: The rough endoplasmic reticulum is studded with ribosomes, not microvilli, mitochondria, or lysosomes. Ribosomes are responsible for protein synthesis, making them an essential component of the rough endoplasmic reticulum.

Correct Answer: A

Rationale: The cellular membrane is composed of a phospholipid bilayer with cholesterol, proteins, and glycoproteins distributed throughout. Nucleic acids are not found within the cellular membrane. Cholesterol helps maintain membrane fluidity, while proteins and glycoproteins play important roles in cell signaling, transport, and structural support.

Correct Answer: C

Rationale: The correct answer is C: Uracil. Uracil is found in RNA, not DNA. The four nitrogenous bases in DNA are adenine, thymine, cytosine, and guanine. Choice A, Adenine, is a nitrogenous base in DNA. Choice B, Guanine, is another nitrogenous base in DNA. Choice D, Thymine, is also one of the four nitrogenous bases in DNA. Therefore, the correct answer is Uracil (Choice C).

Correct Answer: C

Rationale: The correct answer is C: 'Water, carbon dioxide, and adenosine triphosphate (ATP).' During cellular respiration, glucose is broken down in the presence of oxygen to produce water, carbon dioxide, and ATP. Choice A is incorrect as oxygen is not a product of cell respiration but a reactant. Choice B is incorrect as it lists glucose and oxygen, which are actually reactants in the process. Choice D is incorrect as glucose is not a product of cell respiration but a substrate that is broken down to release energy.

Correct Answer: C

Rationale: Water molecules are held together by hydrogen bonds, which are weak bonds formed between the slightly positive hydrogen atom of one water molecule and the slightly negative oxygen atom of another. Choice A, electrostatic attraction, is a general term for the attraction between opposite charges but does not specifically describe the bonds in water. Choice B, Van der Waals forces, are weak intermolecular forces that arise from temporary fluctuations in electron distribution, not the primary bonds in water. Choice D, oxygen, is incorrect as oxygen is part of the water molecule but not the bond holding water molecules together.