Question

I have a couple biology questions!!

25. How do the excretory systems of animals that secrete uric acid differ from those of animals that excrete urine?
34. Explain why maintaining water balance is part of the process of excreting nitrogenous wastes.

thanks!!

Answer 1

Animal excretory systems that secrete uric acid differ in their conservation of water and excrete nitrogenous waste as a paste or powder, while maintaining water balance is essential in excreting nitrogenous wastes due to the toxicity of ammonia and the need for its conversion to less harmful substances.

Step-by-step explanation:

Excretory Systems and Nitrogenous Wastes

The excretory systems of animals that secrete uric acid, such as birds, terrestrial arthropods, and reptiles, differ from those of animals that excrete urine primarily containing urea, like mammals. In organisms that excrete uric acid, metabolic wastes diffuse into tubules, and through the activity of exchange pumps, ions are transported, altering osmotic pressure and drawing water and wastes into the tubules. Subsequently, water and electrolytes are reabsorbed, and uric acid is excreted as a concentrated paste or powder, which conserves water and is crucial for survival in dry environments.

Maintaining water balance is critical in the process of excreting nitrogenous wastes because these compounds can be toxic. To minimize toxicity, ammonia is converted into less harmful substances like urea or uric acid. This conversion and excretion process require energy and, in the case of urea and especially uric acid, less water for dilution. Therefore, water balance is crucial to efficiently manage and remove these wastes.

Answer 2

25.Nitrogenous wastes in the body tend to form toxic ammonia, which must be excreted. Mammals such as humans excrete urea, while birds, reptiles, and some terrestrial invertebrates produce uric acid as waste. Uricothelic organisms tend to excrete uric acid waste in the form of a white paste or powder.

34.The excretory system removes cellular wastes and helps maintain the salt-water balance in an organism. In providing these functions, excretion contributes to the body's homeostasis, the maintenance of constancy of the internal environment. When cells break down proteins, they produce nitrogenous wastes, such as urea