ATI TEAS 7 Science

Correct Answer: D

Rationale: The correct answer is D: tRNA. Transfer RNA (tRNA) carries amino acids to ribosomes during protein synthesis. tRNA has an anticodon that pairs with the mRNA codon, ensuring the correct amino acid is added to the growing polypeptide chain. A: DNA carries genetic information but does not directly participate in protein synthesis. B: mRNA carries the genetic information from DNA to the ribosomes but does not carry amino acids. C: rRNA is a structural component of ribosomes and helps in protein synthesis but does not carry amino acids to the ribosomes.

Correct Answer: C

Rationale: The correct answer is C: Testosterone. Testosterone is crucial for stimulating sperm production in males as it is the primary male sex hormone responsible for regulating the development of male reproductive tissues. It plays a key role in the production of sperm cells in the testes. Estrogen (A) and Progesterone (B) are female sex hormones and do not have a direct role in sperm production. Insulin (D) is a hormone that regulates blood sugar levels and is not involved in the process of sperm production.

Correct Answer: D

Rationale: The correct answer is D because all the options are valid obstacles to achieving controlled nuclear fusion on Earth. Lack of suitable materials (A) is crucial due to extreme conditions, limited fusion fuels (B) can hinder sustained reactions, and containing plasma (C) is challenging to prevent energy loss. Therefore, all factors must be addressed for successful fusion energy production.

Correct Answer: C

Rationale: The correct answer is C because the main function of the pancreas is to produce enzymes that help digest food. These enzymes are released into the small intestine to break down carbohydrates, proteins, and fats. Choice A is incorrect as the pancreas does not store or break down food. Choice B is incorrect as nutrient absorption primarily occurs in the small intestine, not the pancreas. Choice D is incorrect as regulating blood sugar levels is primarily the role of the endocrine portion of the pancreas, not its main function.

Correct Answer: B

Rationale: The correct answer is B: Myosin. Myosin is the protein complex responsible for the thick filament in the sarcomere. It forms cross-bridges with actin during muscle contraction. Actin (choice A) is the thin filament in the sarcomere. Tropomyosin (choice C) is a regulatory protein that covers the myosin-binding sites on actin when the muscle is at rest. Troponin (choice D) is another regulatory protein that helps regulate muscle contraction by binding calcium ions.