The unequal distribution of positively and negatively charged solutes across the plasma membrane is known as what?

Correct Answer: C

Rationale: The correct answer is C: membrane potential. Membrane potential refers to the difference in electrical charge between the inside and outside of a cell due to the unequal distribution of positively and negatively charged ions across the plasma membrane. This potential difference is crucial for various cellular processes such as nerve conduction and muscle contraction. A: Disequilibrium constant is a term used in chemical reactions to describe the ratio of product concentrations to reactant concentrations at equilibrium, not related to the distribution of charged solutes in a cell. B: Charge separation is a generic term and does not specifically refer to the unequal distribution of charged solutes across the plasma membrane. D: Chemical disequilibrium refers to a state where a system is not at equilibrium in terms of chemical reactions, not directly related to the distribution of charged solutes across the membrane.

Correct Answer: C

Rationale: When a cell is placed in an isotonic solution, the concentration of solutes inside and outside the cell is equal. This balance results in no net movement of water across the cell membrane, leading to the cell maintaining its normal shape and size. Choice A is incorrect because in a hypertonic solution, a cell will shrink due to water leaving the cell. Choice B is incorrect as in a hypotonic solution, a cell will swell due to water entering the cell. Choice D is incorrect as it does not provide any relevant information. Therefore, choice C is the correct answer as the cell will stay the same size in an isotonic solution.

Correct Answer: B

Rationale: The correct answer is B: acidaemia. A pH of 7.3 in the blood indicates an acidic environment, as it is below the normal range of 7.35-7.45. Acidaemia specifically refers to the presence of excess acid in the blood. Choice A, acidosis, refers to a systemic condition of excess acid in the body, not just in the blood. Choice C, alkalosis, is the opposite of acidosis and describes a condition of excess base in the body. Choice D, alkalaemia, is not a recognized term in medical literature and is not used to describe a pH of 7.3 in the blood.

Correct Answer: B

Rationale: The correct answer is B: phospholipid buffering system. Phospholipids are not involved in buffering pH in the body. The other options (A: haemoglobin, C: phosphate, D: protein) are all known chemical buffering systems within the body. Haemoglobin acts as a buffer by binding to and releasing hydrogen ions, phosphate buffering system helps maintain pH balance in the intracellular and extracellular fluids, and proteins like albumin and histidine residues in proteins can act as buffers by accepting or donating protons to regulate pH levels. Therefore, phospholipids do not play a role in chemical buffering systems in the body, making option B the correct answer.

Correct Answer: A

Rationale: The correct answer is A: phosphate. Phosphate is a potent urinary buffer as it helps maintain the acid-base balance in the body by accepting or donating hydrogen ions in the urine. Phosphate plays a crucial role in regulating the pH of urine, making it an effective urinary buffer. Summary: - Phosphate is a potent urinary buffer as it helps regulate the pH of urine. - Haemoglobin is not a urinary buffer, it mainly functions in oxygen transport. - Bicarbonate/carbonic acid primarily acts as an extracellular buffer in the blood, not in the urine. - Proteins do have buffering capacity, but they are not specific to urinary buffering.