Nokea
The liberation of proteins to free amino acids (final digestive step) occur in all of the following EXCEPT:
- A. enterocyte cytoplasm
- B. brush border
- C. small intestine lumen
- D. stomach
Correct Answer: D
Rationale: The liberation of proteins to free amino acids occurs primarily in the small intestine lumen. In the stomach, proteins are broken down into smaller peptides but not fully liberated to amino acids. The enterocyte cytoplasm is where amino acids are absorbed. The brush border aids in absorption but doesn't release proteins to amino acids. Therefore, the correct answer is D (stomach) as it is not the site for the final step of protein digestion.
You may also like to solve these questions
What ion is sometimes used as a second messenger of amino acid-base hormones?
- A. Iron
- B. Calcium
- C. Sodium
- D. Chlorine
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
The clusters of cells in the pancreas that produce hormones are the .
- A. islets of Langerhans
- B. pancreatic medulla
- C. pancreatic cortex
- D. nodules
Correct Answer: A
Rationale: The correct answer is A: islets of Langerhans. These clusters of cells in the pancreas are responsible for producing hormones such as insulin and glucagon. They play a crucial role in regulating blood sugar levels. The other choices, B: pancreatic medulla, C: pancreatic cortex, and D: nodules, are incorrect as they do not accurately describe the specific clusters of cells in the pancreas responsible for hormone production. It is important to understand the function and location of the islets of Langerhans to grasp the endocrine role of the pancreas.
The 'hormone response element' is located on the cell __________.
- A. membrane
- B. DNA
- C. RNA
- D. enzymes
Correct Answer: B
Rationale: The correct answer is B: DNA. Hormone response elements are specific DNA sequences where hormone receptors bind to regulate gene expression. This binding initiates the transcription of target genes. Choices A, C, and D are incorrect because hormone response elements are not located on the cell membrane, RNA, or enzymes. The key is understanding that hormone receptors act on DNA to regulate gene expression, making choice B the most appropriate answer.
Which of the following hormones acts on its target tissues by a steroid hormone mechanism of action?
- A. Thyroid hormone
- B. Parathyroid hormone (PTH)
- C. Antidiuretic hormone (ADH) on the collecting duct
- D. β1 adrenergic agonists
Correct Answer: A
Rationale: The correct answer is A: Thyroid hormone. Thyroid hormone acts on its target tissues by a steroid hormone mechanism of action because it is a lipid-soluble hormone that can diffuse through cell membranes and bind to intracellular receptors. These hormone-receptor complexes then directly regulate gene expression. In contrast, choices B, C, and D do not follow a steroid hormone mechanism of action. Parathyroid hormone (PTH) acts through G-protein coupled receptors, Antidiuretic hormone (ADH) acts through V2 receptors, and β1 adrenergic agonists act through beta-adrenergic receptors, which are all distinct from the mechanism of action of steroid hormones.
The secretions from which of these glands differs between males and females?
- A. Adrenal.
- B. Parathyroid.
- C. Gonadal.
- D. Pancreas.
Correct Answer: C
Rationale: The correct answer is C: Gonadal. The secretions from gonads (testes in males, ovaries in females) differ between males and females due to the production of sex hormones (testosterone in males, estrogen and progesterone in females). Adrenal glands (A) secrete similar hormones in both genders. Parathyroid (B) and Pancreas (D) do not secrete hormones that differ based on gender.