In a graph of glomerular filterability vs. effective molecular radius, if X and Y are two molecules, which statement is correct?

  1. Y has more filterability than X 

2. Y has more filterability than Z 

3. X has less filterability than Y 

4. X represents positively charged molecules

A. 1 and 2

B. 2 and 3

C. 3 and 4

D. 1 and 4

Answer: C

1. A

   A. 1 and 2

2. B

   B. 2 and 3

3. C

   C. 3 and 4

4. D

   D. 1 and 4

Appeared in: INI-CET EXAM -2026

Explanation

• Statement 2 is correct because the graph shows the curve for Y (representing neutral molecules) is consistently above the curve for Z (representing anionic molecules), indicating higher filterability for any given molecular size.
• Statement 4 is correct because the glomerular filtration barrier is negatively charged. Therefore, positively charged molecules (cations) are attracted to it and exhibit the highest filterability for a given size, which corresponds to curve X on the graph.
• 2 and 4 matches the defining clue or classification criterion in the stem.
• Supporting mechanism: The option aligns with the underlying pathophysiology, nursing rationale, procedure logic, or assessment principle being tested.
• Key differentiator: It fits the one fact that separates the correct response from the closest distractor.

Why Other Options Were Wrong

• Option A: This option is incorrect because it includes statement 1, which is false. The graph shows that molecule X has higher, not lower, filterability than molecule Y.
• Option B: This option is incorrect because it includes statement 3, which is false. The graph clearly indicates that molecule X has more, not less, filterability than molecule Y.
• Option D: This option is incorrect because it includes statement 1, which is false. According to the graph, molecule X's filterability is greater than molecule Y's.

Related Visual

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Factors affecting glomerular filtration (molecular size and charge) as background academic context rather than a clinical decision trigger.
• In normal physiology, the combination of size and charge restriction by the glomerular barrier is crucial for preventing the loss of essential plasma proteins like albumin into the urine.
• In diseases like nephrotic syndrome (e.g., minimal change disease), the negative charge of the barrier is lost. This allows proteins like albumin to leak into the filtrate, causing heavy proteinuria, edema, and hypoalbuminemia, which are key diagnostic signs of kidney damage.
• A nurse monitoring a patient with suspected kidney disease would assess for proteinuria using a urine dipstick test. The presence of protein in the urine is a significant finding that warrants further investigation of glomerular function.

How to Approach the Question

• First, analyze the graph's axes and curves. Note that filterability (y-axis) decreases as molecular size (x-axis) increases. Also, observe the relative positions: for any given size, filterability is X > Y > Z.
• Next, recall the core physiological principle of the glomerular filtration barrier: it possesses a strong negative charge.
• Connect the physiology to the graph. The negative barrier will attract positive molecules (cations), giving them the highest filterability (Curve X). It will have no charge-based interaction with neutral molecules (intermediate filterability, Curve Y). It will repel negative molecules (anions), giving them the lowest filterability (Curve Z).
• Systematically evaluate each of the four statements based on your analysis of the graph and your physiological understanding.
• Identify the statements that are factually correct. In this case, statements 2 and 4 are correct.
• Finally, select the option from the choices that combines the correct statements.

Concept Tested & Keywords

• Concept Tested: Factors affecting glomerular filtration (molecular size and charge)
• Stem keywords: glomerular filterability, effective molecular radius, graph, molecule
• Lead-in keywords: which statement is correct
• Negative lead-in flag: false

Question ID

QDU6ntT1gRIjpbyXrwGZC4

Copy ID

Reference Book

E6 Physiology Guyton 4SAE Part 2B p. 20-22