Passage
Within the Actinopterygii (bony fish) lineage, marine teleosts (bony fish with mobile jaws) live in an aquatic environment where there is a higher external concentration of salt and a lower concentration of water relative to the internal concentrations. Owing to these conditions, salt ions tend to diffuse into the teleost through its skin, whereas water molecules within the organism osmotically traverse the opposite path.Irrespective of lineage, many fish species actively assess their environment and regulate their internal concentration of fluids and electrolytes via a homeostatic process known as osmoregulation. Teleosts with either glomerular kidneys (eg, eels, sculpin) or aglomerular kidneys that are purely tubular (eg, goosefish, toadfish) have served as experimental subjects for the study of marine teleost osmoregulation. Analyzing the ionic (ie, Na + , Cl − , Mg 2+ , SO 4 2− ) concentration of intestinal fluids, urine, and plasma in each species led to the discovery that the renal tubule of the goosefish has both excretory and reabsorptive functions.Scientists have concluded that marine teleost osmoregulation involves the ingestion of seawater, retrieval of NaCl and water from the intestine, and primary excretion of divalent ions via urine and monovalent ions through the gills (thin barriers between the organism's blood and the aquatic environment).In an experiment to further study osmoregulatory mechanisms, researchers emptied the gut of an eel and sealed the anus to prevent fluid loss. The eel was transported into seawater that had been treated with the volume marker phenol red. After 20 hours, the eel's gut contained 2.3 mL of fluid but showed a phenol red concentration equivalent to 12.3 mL of ingested seawater. Researchers found that the eel lost 2.3 g of weight due to urine output. They ultimately reported that the eel had lost all the seawater it absorbed through the gut via various mechanisms.
-Researchers studying marine teleosts claim that the glomerular kidney is 500 times as efficient as the aglomerular kidney in eliminating nontoxic substances. Similar amounts of nontoxic ferrocyanide are intramuscularly injected into a sculpin and a goosefish of comparable weight. Given this, which of the following tables showing renal elimination of ferrocyanide after 5 hours would support the researchers' claim?

Question

Passage
Within the Actinopterygii (bony fish) lineage, marine teleosts (bony fish with mobile jaws) live in an aquatic environment where there is a higher external concentration of salt and a lower concentration of water relative to the internal concentrations.  Owing to these conditions, salt ions tend to diffuse into the teleost through its skin, whereas water molecules within the organism osmotically traverse the opposite path.Irrespective of lineage, many fish species actively assess their environment and regulate their internal concentration of fluids and electrolytes via a homeostatic process known as osmoregulation.  Teleosts with either glomerular kidneys (eg, eels, sculpin) or aglomerular kidneys that are purely tubular (eg, goosefish, toadfish) have served as experimental subjects for the study of marine teleost osmoregulation.  Analyzing the ionic (ie, Na + , Cl − , Mg 2+ , SO 4 2− ) concentration of intestinal fluids, urine, and plasma in each species led to the discovery that the renal tubule of the goosefish has both excretory and reabsorptive functions.Scientists have concluded that marine teleost osmoregulation involves the ingestion of seawater, retrieval of NaCl and water from the intestine, and primary excretion of divalent ions via urine and monovalent ions through the gills (thin barriers between the organism's blood and the aquatic environment).In an experiment to further study osmoregulatory mechanisms, researchers emptied the gut of an eel and sealed the anus to prevent fluid loss.  The eel was transported into seawater that had been treated with the volume marker phenol red.  After 20 hours, the eel's gut contained 2.3 mL of fluid but showed a phenol red concentration equivalent to 12.3 mL of ingested seawater.  Researchers found that the eel lost 2.3 g of weight due to urine output.  They ultimately reported that the eel had lost all the seawater it absorbed through the gut via various mechanisms.
-Researchers studying marine teleosts claim that the glomerular kidney is 500 times as efficient as the aglomerular kidney in eliminating nontoxic substances.  Similar amounts of nontoxic ferrocyanide are intramuscularly injected into a sculpin and a goosefish of comparable weight.  Given this, which of the following tables showing renal elimination of ferrocyanide after 5 hours would support the researchers' claim?

Quizplus · Accepted Answer

The nephron is the functional unit of the kidney, composed of a glomerulus and tubular segments. The glomerulus, a ball-like network of capillaries, filters blood plasma into the tubular segments of the nephron. The filtered plasma, known as the renal filtrate, enters the tubular segments, where the concentration of nutrients, electrolytes, water, and other substances is regulated via excretory and secretory processes to ultimately produce urine. Based on the passage, some fish species have glomerular kidneys (eg, sculpin) and some have aglomerular kidneys (eg, goosefish). The researchers' claim is that the glomerular kidney is 500 times as efficient as the aglomerular kidney in eliminating nontoxic substances. In the given scenario, a sculpin and a goosefish of comparable weight were injected with similar volumes of nontoxic ferrocyanide. The question asks for a result in the glomerular sculpin and aglomerular eel that would support the researchers' claim regarding kidney efficiency in glomerular and aglomerular species. The only table that supports their hypothesis is Choice D, which shows that 5 hours after injection, the sculpin eliminated 5 percent of the ferrocyanide ion but that the goosefish eliminated only 0.01 percent. The exact level of increased ferrocyanide elimination in the glomerular sculpin compared to the aglomerular goosefish can be calculated as follows: 11ecba2d_1029_4f35_a3bf_ed4382be5567_MD0008_00 % ferrocyanide eliminated by glomerular sculpin% ferrocyanide eliminated by aglomerular goosefish=5%0.01%=51%1100% Dividing one fraction by another fraction is equivalent to multiplying the first fraction by the reciprocal of the second fraction, so the equation can be rewritten as: 11ecba2d_1029_4f36_a3bf_694dc8bd6768_MD0008_00 511100=51×1001=500 Therefore, the results in this table show that the glomerular kidney is 500 times as efficient in eliminating ferrocyanide as the aglomerular kidney. (Choice A) Calculating 0.1/0.005 would show that the glomerular kidney is 20 times as efficient in eliminating ferrocyanide as the aglomerular kidney. (Choice B) Calculating 10/0.05 would show that the glomerular kidney is 200 times as efficient in eliminating ferrocyanide as the aglomerular kidney. (Choice C) Calculating 0.5/0.01 would show that the glomerular kidney is 50 times as efficient in eliminating ferrocyanide as the aglomerular kidney. Educational objective: As the functional unit of the kidney, the nephron consists of a ball-like network of capillaries called the glomerulus. The glomerulus filters blood plasma into the tubular segments of the nephron.

Passage Within the Actinopterygii (Bony Fish) Lineage, Marine Teleosts (Bony Fish