ATI TEAS 7 Science

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.

Correct Answer: A

Rationale: The correct answer is A: Stapes. The stapes is the smallest bone in the human body, located in the middle ear. It plays a crucial role in transmitting sound vibrations to the inner ear. The other choices are incorrect because the patella is a knee bone, phalanges are finger bones, and ribs are chest bones, none of which are the smallest bone in the body. The stapes' small size and specific location make it uniquely suited for its function in hearing.

Correct Answer: A

Rationale: The correct answer is A: Calcitonin. Calcitonin is produced by the thyroid gland and functions to lower blood calcium levels by promoting calcium deposition in bones and inhibiting calcium reabsorption in the kidneys. This hormone opposes the action of parathyroid hormone (PTH), which increases blood calcium levels by promoting calcium release from bones and increasing calcium reabsorption in the kidneys. Thyroxine is a thyroid hormone that regulates metabolism and growth, not calcium levels. Insulin is a hormone produced by the pancreas that regulates blood sugar levels, not calcium levels. Thus, A is the correct answer as it directly regulates calcium levels in the blood through its actions on bones and kidneys.

Correct Answer: B

Rationale: The correct answer is B: Blood pressure. Blood pressure is the term for the pressure exerted by blood against the walls of blood vessels. It is a crucial indicator of cardiovascular health. Heart rate (A) is the number of times the heart beats per minute, not directly related to blood vessel pressure. Cardiac output (C) is the amount of blood pumped by the heart per minute, not the pressure exerted on blood vessel walls. Stroke volume (D) is the volume of blood pumped by the heart in a single contraction, not the pressure against blood vessel walls.

Correct Answer: C

Rationale: The correct answer is C: Testes. The testes are responsible for producing testosterone, a male sex hormone. They contain specialized cells called Leydig cells that produce testosterone. The adrenal glands (A) produce hormones like cortisol and adrenaline, not testosterone. The pituitary gland (B) regulates hormone production but does not directly produce testosterone. The pancreas (D) produces insulin and other digestive enzymes, not testosterone. Therefore, the testes are the correct answer for testosterone production.