ATI TEAS Practice Science Test

Correct Answer: A

Rationale: The correct answer is A: Cell. Cells are the most basic unit of structure in living things because they are the building blocks of all living organisms. Cells perform all the necessary functions for life, such as growth, reproduction, and energy production. Organelles are structures within cells, not the basic unit themselves. Oxygen is a vital component for life but not a structural unit. Pigments are molecules that give color and have specific functions in organisms but are not the basic unit of structure. Therefore, the correct choice is A: Cell.

Correct Answer: B

Rationale: The purpose of an electrocardiogram (ECG) is to display the heart's rate and rhythm. It measures the electrical activity of the heart, showing how well it is functioning. By analyzing the ECG waveform, healthcare providers can assess the heart's health, detect any abnormalities, and diagnose various heart conditions. It provides crucial information about the heart's electrical impulses, such as the heart rate, rhythm, and any potential irregularities like arrhythmias. Therefore, choice B is correct. Choices A, C, and D are incorrect because an ECG does not indicate the rate of blood flow, identify a person's blood group type, or determine cell type in a blood sample.

Correct Answer: B

Rationale: The correct answer is B because urine is formed in the kidney during the process of fluid filling the collecting duct. This is where the final concentration and composition of urine are regulated. Before reaching the collecting duct, the initial filtration of blood occurs in the glomerulus (eliminating options C) and the fluid does not become urine until it has passed through the collecting duct (eliminating options A and D). So, the correct sequence is filtration in the glomerulus, reabsorption and secretion in the tubules, and final urine formation in the collecting duct.

Correct Answer: B

Rationale: The correct answer is B: Cytoplasm. Pyruvate is an intermediate product of glycolysis, which occurs in the cytoplasm of the cell. The biochemist isolating pyruvate is working with the cytoplasm because that's where glycolysis takes place. Chloroplasts (A) are involved in photosynthesis, not glycolysis. Mitochondria (C) are responsible for aerobic respiration, where pyruvate is eventually transported to. The nucleus (D) contains the cell's genetic material and is not directly involved in pyruvate metabolism. Thus, the biochemist is likely isolating pyruvate from the cytoplasm.

Correct Answer: A

Rationale: The correct answer is A: Adenine. Adenine forms a complementary base pair with cytosine through hydrogen bonding in DNA. This pairing is essential for maintaining the structure and stability of the DNA double helix. Adenine and cytosine form two hydrogen bonds between them. Choices B, C, and D are incorrect because cytosine does not bind with itself (B), guanine (C), or thymine (D) in DNA. Thymine pairs with adenine, while guanine pairs with cytosine. Therefore, the correct base that binds with cytosine is adenine.