ati teas 7 science

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.

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: B

Rationale: The correct answer is B (25 grams) as the recommended daily fiber intake for adults by the American Heart Association is 25-30 grams. Fiber helps with digestion, heart health, and weight management. Option A (10 grams) is too low and insufficient for daily needs. Option C (35 grams) and D (50 grams) are excessive and may lead to digestive issues like bloating or gas. Therefore, B is the most appropriate choice for optimal health benefits.

Correct Answer: B

Rationale: Insulin is the correct answer as it is responsible for lowering blood sugar levels by promoting the uptake of glucose into cells. Glucagon raises blood sugar levels, adrenaline and cortisol are stress hormones that increase blood sugar levels. Therefore, the correct choice is B.

Correct Answer: C

Rationale: The primary function of the lymphatic system is to fight infection and remove excess fluid. Lymph nodes contain white blood cells that help fight pathogens. Lymphatic vessels collect excess fluid from tissues and transport it back to the bloodstream, aiding in immune response. Other choices are incorrect because A: Oxygen transport is primarily done by the circulatory system, B: Blood filtration is mainly carried out by the kidneys, and D: Hormone transport is primarily through the circulatory system.