Answer to Question #59102 in Cell Biology for Tracy Guido

Question

30
Freshwater and marine fish inhabit waters with different osmotic properties, so they regulate osmolarity in different ways. Classify each of the osmoregulation properties as relevant to freshwater fish or marine fish.
1. ingest large amounts of water and salt through mouth. 2. constantly gain water by osmosis. 3. excrete large amounts of water in urine. 4. gain salt ions through gills.
5. constantly lose water by osmosis. 6. excrete large amount of salt in urine. 7. Excrete large amounts of salt through gills. 8. Ingest little to no water by mouth.

31.
What is the primary benefit for an animal to excrete nitrogenous waste as uric acid?
Uric acid requires less energy to synthesize than urea.
Uric acid helps an animal to conserve water.
Uric acid increases efficiency of kidney function.
Uric acid improves gastric absorption of nucleic acids.

Answer 1

30.1. ingest large amounts of water and salt through mouth -marine
2. constantly gain water by osmosis - freshwater
3. excrete large amounts of water in urine - freshwater
4. gain salt ions through gills - marine
5. constantly lose water by osmosis - marine
6. excrete large amount of salt in urine - marine
7. Excrete large amounts of salt through gills - marine
8. Ingest little to no water by mouth - freshwater

31. Correct answer:Uric acid helps an animal to conserve water.
Terrestrial animals, which have to conserve water at the high rate, often elease uric acid as a waste product. It requires significant energy input and does not pose the effects suggested by other options.