HESI A2 Biology Practice Test

Correct Answer: B

Rationale: Thymine is not present in RNA because thymine is a pyrimidine base found in DNA instead of RNA. RNA contains uracil as its complementary base to adenine, while DNA contains thymine. Adenine, uracil, and cytosine are all present in RNA, making them incorrect choices. Thymine is the only base not present in RNA, making option B the correct answer.

Correct Answer: B

Rationale: Thymine is not present in RNA because thymine is a pyrimidine base found in DNA instead of RNA. RNA contains uracil as its complementary base to adenine, while DNA contains thymine. Adenine, uracil, and cytosine are all present in RNA, making them incorrect choices. Thymine is the only base not present in RNA, making option B the correct answer.

Correct Answer: D

Rationale: The correct answer is D because all the statements mentioned in choices A, B, and C are true. A: The respiratory system consists of all organs involved in breathing, including the nose, pharynx, larynx, trachea, bronchi, and lungs. B: Organs included in the respiratory system are the nose, pharynx, larynx, trachea, bronchi, and lungs. C: The respiratory system conveys oxygen into our bodies and removes carbon dioxide from our bodies. Therefore, as all three statements are true, the correct answer is D - All of the Above. The other choices are incorrect because they do not encompass all the organs involved in the respiratory system or the functions it performs.

Correct Answer: A

Rationale: The correct answer is A: DNA-RNA-protein. This process is known as protein synthesis or gene expression. It starts with DNA being transcribed into RNA by RNA polymerase. The RNA then undergoes translation, where ribosomes read the RNA sequence and assemble amino acids into a protein. Choice B is incorrect because genes are segments of DNA, not chromosomes. Choice C is incorrect because ATP is not involved in protein synthesis. Choice D is incorrect because RNA is transcribed from DNA, not the other way around.

Correct Answer: D

Rationale: Cytokinesis occurs to physically separate the two daughter cells after cell division. This process ensures that each daughter cell receives a complete set of organelles and genetic material. The correct answer, choice D, states that daughter cells can divide, which aligns with the purpose of cytokinesis. Choices A and B are incorrect as they do not directly relate to the process of cytokinesis. Choice C is also incorrect as cytokinesis is not primarily involved in killing bacteria, but rather in ensuring successful cell division.