Table of Contents
Why do sharks excrete urea?
In particular, unlike other vertebrates, sharks have a skeletal cartilage structure rather than bone structure. Urea and trimethylamine in their blood and tissues help maintain their osmotic balance. They have no ordinary urinary tract, so they concentrate urea in their blood and excrete it through their skin.
Why do whales excrete urea?
The cartilaginous fishes which excrete urea are often the salt water fishes. Whales, for instance, use urea in the blood to make them hyperosmotic in relation to seawater, thus they tend to gain water from the ocean and do not have to worry about dehydration.
Do whales excrete ammonia or urea?
Organisms that excrete urea as their nitrogenous waste are called as ureotelic organisms. They include man, whales, seals, desert mammals like kangaroo rats, camels, toads, frogs, cartilagenous fishes, aquatic and semi aquatic reptiles like alligator, terrapins and turtles.
Do sharks excrete ammonia?
Like other fishes, sharks excrete nitrogenous wastes over their gills. The teleosts, or bony fishes, excrete nitrogenous wastes in the form of ammonia. Ammonia is a very toxic compound, and excretion of ammonia requires passing large amounts of water over the gills.
Why do sharks have ammonia?
Unprocessed shark meat may have a strong odor of ammonia, due to the high urea content that develops as the fish decomposes.
Are sharks attracted to ammonia?
Far from being repelled by ammonia, sharks are actually attracted to it. Sea creatures can make urea too, though—and in sharks this molecule, which they synthesise in their gills, plays a crucial role in stabilising the salinity of their tissues.
How does urea work in sharks?
Urea is a nitrogen-containing substance that the shark stores in its blood. By doing so, the shark is able to retain fluid, which prevents the skin from drying out in saltwater conditions.
Do sharks store urea?
Sharks — all ocean sharks, and rays, and skates — retain urea so that their bodies are at the same salt concentration as the salt water outside. So to balance the urea and protect its tissue, sharks also have high concentrations of a compound called trimethylamine oxide, or TMAO.
What is shark urea?
Animals typically eat protein in order to grow, but sharks also require protein to continually replenish urea in their tissues. The urea—the non-toxic nitrogen-containing substance which humans excrete in their urine—keeps the fish from drying out in salty seawater.
Why do mammals excrete urea and not ammonia?
Urea is more water soluble than uric acid (Almost insoluble substance). Urea is also more toxic. Both however are less toxic than ammonia. Urea is less toxic and requires less water to remove from organism (so it’s better in terrestrial environment) but it requires more energy to produce.
Why do Sharks excrete urea?
Sharks, on the other hand, excrete nitrogenous wastes as urea, which is a less toxic compound. A complex biochemical pathway called the ornithine-urea cycle converts ammonia to urea, which can be stored more safely in the blood. In a live shark, ammonia doesn’t accumulate because it is quickly converted to urea.
What animals excrete urea instead of ammonia?
Ureotelic animals excrete urea instead of ammonia as the major nitrogenous waste product. These include man and all other mammals, terrestrial and semi-aquatic amphibians such as toads and frogs, cartilaginous fishes (elasmobranchs) such as sharks and sting rays.
Is a shark a ureotelic animal?
Answer: (d) Sharks are ureotelic, they are not ammonotelic animals. Ureotelic animals excrete urea instead of ammonia as the major nitrogenous waste product. These include man and all other mammals, terrestrial and semi-aquatic amphibians such as toads and frogs, cartilaginous fishes (elasmobranchs) such as sharks and sting rays.
What happens to ammonia when a shark dies?
In a live shark, ammonia doesn’t accumulate because it is quickly converted to urea. When the shark dies, the urea deteriorates back into ammonia, which is why shark meat often tastes and smells of ammonia.