Nokea
Which of the following hormones contributes to the regulation of the body’s fluid and electrolyte balance?
- A. adrenocorticotropic hormone
- B. antidiuretic hormone
- C. luteinizing hormone
- D. all of the above
Correct Answer: B
Rationale: The correct answer is B, antidiuretic hormone (ADH). ADH regulates the body's fluid balance by controlling the amount of water reabsorbed by the kidneys. This helps maintain proper hydration levels and electrolyte balance. Adrenocorticotropic hormone (A) regulates cortisol production, not fluid balance. Luteinizing hormone (C) plays a role in reproductive functions, not fluid balance. Option D is incorrect because only antidiuretic hormone is directly involved in regulating fluid and electrolyte balance.
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Glucagon
- A. Accelerates protein synthesis within cells
- B. Accelerates the conversion of glycogen into glucose
- C. Decreases the conversion of glycogen into glucose
- D. Slows down glucose formation from lactic acid
Correct Answer: B
Rationale: Rationale: Glucagon stimulates the breakdown of glycogen stored in the liver into glucose, increasing blood glucose levels. This process, called glycogenolysis, is crucial during times of low blood sugar to maintain energy levels. Therefore, choice B is correct. Choices A, C, and D are incorrect because glucagon does not directly affect protein synthesis within cells, decrease glycogen conversion into glucose, or slow down glucose formation from lactic acid.
Which of the following hormones does the skin produce?
- A. erythropoietin
- B. melatonin
- C. renin
- D. cholecalciferol
Correct Answer: D
Rationale: The correct answer is D: cholecalciferol. The skin produces cholecalciferol, also known as vitamin D, in response to sunlight exposure. This hormone plays a crucial role in calcium absorption and bone health. Erythropoietin (A) is produced by the kidneys to stimulate red blood cell production. Melatonin (B) is produced by the pineal gland to regulate sleep-wake cycles. Renin (C) is produced by the kidneys to regulate blood pressure. Therefore, the skin does not produce erythropoietin, melatonin, or renin, making them incorrect choices.
What is the definition of a gene?
- A. all the DNA in a cell that controls metabolic reactions
- B. a length of DNA that codes for a protein
- C. the nucleus and its chromosomes
- D. all the DNA in a cell that determines the inheritance of sex
Correct Answer: B
Rationale: The correct answer is B: a length of DNA that codes for a protein. Genes are specific sequences of DNA that encode instructions for building proteins. This is the fundamental role of genes in the process of protein synthesis. Choice A is incorrect because not all DNA in a cell controls metabolic reactions; some DNA is non-coding. Choice C is incorrect as it refers to the entire nucleus and its contents, not just the gene. Choice D is incorrect as genes do not solely determine the inheritance of sex; they also code for other traits. In summary, the definition of a gene as a segment of DNA that codes for a protein aligns with the known function and role of genes in genetics and molecular biology.
Chief cells secrete:
- A. HCl
- B. pepsinogen
- C. intrinsic factor
- D. HCO3-
Correct Answer: B
Rationale: Chief cells in the gastric glands of the stomach secrete pepsinogen. Pepsinogen is an inactive precursor of pepsin, which is an enzyme responsible for breaking down proteins. This process aids in the digestion of proteins in the stomach. Chief cells do not secrete HCl (A), which is secreted by parietal cells. Intrinsic factor (C) is secreted by parietal cells and is essential for vitamin B12 absorption, not by chief cells. HCO3- (D) is secreted by the pancreas to neutralize stomach acid in the duodenum, not by chief cells in the stomach.
Which of the following hormones is responsible for the fight-or-flight response?
- A. Epinephrine & norepinephrine
- B. Insulin & glucagon
- C. Estrogen & progesterone
- D. Thyroxin & melatonin
Correct Answer: A
Rationale: The correct answer is A: Epinephrine & norepinephrine. These hormones are responsible for the fight-or-flight response. When facing a threat, the adrenal glands release these hormones, which increase heart rate, blood pressure, and energy levels to prepare the body to either fight or flee. Epinephrine and norepinephrine are part of the sympathetic nervous system's response to stress.
Choices B, C, and D are incorrect:
B: Insulin & glucagon regulate blood sugar levels, not the fight-or-flight response.
C: Estrogen & progesterone are reproductive hormones, not involved in the fight-or-flight response.
D: Thyroxin & melatonin regulate metabolism and sleep-wake cycles, respectively, not the fight-or-flight response.