ATI TEAS 7 Science

Correct Answer: B

Rationale: The correct answer is B: Pivot joint. Pivot joints allow rotational movement around a single axis, such as the rotation of the radius around the ulna in the forearm. This type of joint is designed to facilitate the turning or twisting motion. Ball-and-socket joints (A) allow for multi-axial movement, hinge joints (C) enable movement in one direction like a door hinge, and saddle joints (D) have two saddle-shaped surfaces that allow for movement in multiple directions, but not specifically rotational movement around a single axis.

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: 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: A

Rationale: The correct answer is A: Meters per second. The speed of light in a vacuum is a measure of how fast light travels, which is approximately 299,792,458 meters per second. This unit is commonly used in physics to quantify the speed of light. Hertz (B) is a unit of frequency, Candela (C) is a unit of luminous intensity, and Newton (D) is a unit of force, not speed. Therefore, A is the correct unit to measure the speed of light in a vacuum.

Correct Answer: B

Rationale: The correct answer is B: Peptide bond. A peptide bond is a covalent bond that connects amino acids in a protein chain. During protein synthesis, the carboxyl group of one amino acid reacts with the amino group of another amino acid, forming a peptide bond. This bond is crucial for the structural integrity and function of proteins. A: Covalent bonds are generic chemical bonds that can occur between any atoms, not specifically between amino acids in proteins. C: Ionic bonds involve the transfer of electrons between atoms with opposite charges, which is not how amino acids are connected in proteins. D: Hydrogen bonds are weak interactions between hydrogen and electronegative atoms, not the primary bond connecting amino acids in proteins.