What ion is sometimes used as a second messenger of amino acid-base hormones?

Correct Answer: B

Rationale: The correct answer is B: Calcium. Calcium ions are commonly used as second messengers for amino acid-base hormones due to their ability to trigger various cellular responses. When the hormone binds to its receptor on the cell surface, it activates specific signaling pathways that lead to an increase in intracellular calcium levels. This rise in calcium ions then initiates downstream signaling cascades, ultimately regulating processes such as gene expression, cell growth, and metabolism. Choice A - Iron: Iron is not typically involved in signaling pathways for amino acid-base hormones. It is more commonly known for its role in oxygen transport and storage in hemoglobin. Choice C - Sodium: While sodium ions play essential roles in cellular functions, they are not typically utilized as second messengers for amino acid-base hormones. Sodium is more commonly associated with maintaining cell membrane potential and fluid balance. Choice D - Chlorine: Chlorine ions are not typically involved in signaling pathways for amino acid-base hormones. Chlorine is primarily known for its role in maintaining

Correct Answer: C

Rationale: The correct answer is C: growth hormone does not promote glucose metabolism. Growth hormone primarily promotes protein synthesis in bones, cartilage, and muscles (B), stimulates the rate of amino acid entrance into the cell (A), and promotes fat metabolism (D). Glucose metabolism is mainly regulated by insulin, not growth hormone.

Correct Answer: A

Rationale: The correct answer is A: sympathetic. Epinephrine and norepinephrine are neurotransmitters released by the sympathetic nervous system. They activate the fight-or-flight response, increasing heart rate, dilating airways, and redirecting blood flow to muscles. The sympathetic nervous system prepares the body for action in response to stress or danger. Choices B, C, and D are incorrect because parasympathetic regulates rest and digest functions, somatic controls voluntary movements, and central refers to the brain and spinal cord, not a division of the autonomic nervous system like sympathetic.

Correct Answer: D

Rationale: Sure! The correct answer is D because type I diabetes (IDDM) is characterized by the body's inability to produce insulin, leading to high blood sugar levels. Insulin injections are necessary to replace the missing insulin. A is incorrect because type I diabetes is not associated with obesity. B is incorrect because type II diabetes is actually the most common form. C is incorrect because in type I diabetes, the body's cells do not produce insulin, rather than not responding to it.

Correct Answer: C

Rationale: The correct answer is C: Epinephrine and norepinephrine. These hormones are responsible for the 'fight-or-flight' response. When the body perceives a threat, these hormones are released by the adrenal glands, preparing the body for a rapid response to danger. Epinephrine increases heart rate, blood pressure, and blood flow to muscles, while norepinephrine helps maintain alertness and focus. Choice A (Thyroxine and melatonin) are hormones involved in regulating metabolism and sleep-wake cycles, not the 'fight-or-flight' response. Choice B (Insulin and glucagon) are hormones that regulate blood sugar levels, not the 'fight-or-flight' response. Choice D (Oestrogen and progesterone) are reproductive hormones that regulate the menstrual cycle and pregnancy, not the 'fight-or-flight' response.