ATI TEAS Practice Test Science

Correct Answer: B

Rationale: The main function of red blood cells is to carry oxygen from the lungs to all the body's tissues and organs, where it is needed for cellular functions and metabolism. This process is essential for sustaining life and providing energy to cells. Choice A is incorrect because fighting infection is primarily done by white blood cells. Choice C is incorrect because antibody production is mainly carried out by specialized white blood cells. Choice D is incorrect as the primary role of red blood cells is not to transport waste, but rather to transport oxygen and some carbon dioxide.

Correct Answer: C

Rationale: Adrenaline is the correct answer. It is released by the adrenal glands in response to stress to prepare the body for the 'fight or flight' response. Adrenaline increases heart rate, dilates airways, and mobilizes energy stores to help the body deal with the perceived threat. Insulin (Choice A) is produced by the pancreas to regulate blood sugar levels, not in response to stress. Cortisol (Choice B) is another hormone released by the adrenal glands in response to stress, but it primarily helps regulate metabolism and immune response. Glucagon (Choice D) is also produced by the pancreas to increase blood sugar levels when they are low, not by the adrenal glands in response to stress.

Correct Answer: B

Rationale: The correct answer is B: Deoxyribose. DNA is composed of nucleotides containing deoxyribose sugar, phosphate group, and nitrogenous bases (adenine, thymine, guanine, and cytosine). Deoxyribose is the sugar component specific to DNA, while ribose is found in RNA. Guanine (choice C) is a nitrogenous base present in both DNA and RNA. Uracil (choice A) is a nitrogenous base specific to RNA, replacing thymine found in DNA. The phosphate group (choice D) is an essential part of nucleotides in both DNA and RNA, providing the backbone structure for the nucleic acid chains.

Correct Answer: C

Rationale: Chromosomes, which contain genetic information, are found in the nucleus of a cell. They play a crucial role in cell division, gene expression, and inheritance. Mitochondria, responsible for energy production, are located in the cytoplasm, not the nucleus. The endoplasmic reticulum is mainly involved in protein and lipid synthesis and is not a component of the nucleus. Ribosomes, essential for protein synthesis, are found in the cytoplasm and on the endoplasmic reticulum, but not in the nucleus.

Correct Answer: D

Rationale: The correct answer is Polymerase. Polymerase is the enzyme responsible for adding nucleotides to a growing DNA chain during DNA replication. Helicase unwinds the DNA double helix to separate the DNA strands for replication, Ligase joins DNA fragments together by catalyzing the formation of phosphodiester bonds between them, and Nuclease cuts or degrades DNA strands. Therefore, choices A, B, and C are incorrect in the context of adding nucleotides to a growing DNA chain.