The type of nitrogenous waste an organism produces varies depending upon its env
ID: 213192 • Letter: T
Question
The type of nitrogenous waste an organism produces varies depending upon its environment (where it lives), how its embryos develop and desires to conserve water or energy. Organisms will generally produce mainly one of three nitrogenous wastes from amine groups (NH2). Their names, chemical structures and relative toxicity are as follows. (Hint: their structure is a reflection of how much energy it takes to produce them and everyone like to save energy IF they can, but will spend it if it's worth it. Hint 2: think of how you can make something toxic less toxic . Ammonia (NH3) pretty toxic (esp. in concentrated form) Urea (CON2H) less toxic than ammonia Uric Acid (CsO3N4H4) - least toxic of the three Answer questions 1-4 1. Where do the amino groups come from (Hint: what do they sound like and what are those subunits of, this is something you should have learned in biol 1110)? 2. If you were a fish, which nitrogenous waste would you produce and why (what are the advantages of producing this particular waste)? 3. If you were a bird reptile, which waste would you produce and why (hint: why do you think birds and reptiles are paired? This is something covered in the vertebrate diversity chapter.)? 4. If you were a land dwelling mammal, which waste would you produce and why?Explanation / Answer
1) One of the most important biological molecule of our body is protein. This is made up of several amino acids joined together by peptide bond. Now, everyday, proteins are used up for different purposes. It undergoes digestion, destruction and again newly translation.
Aminoacid has amine group attached to it. When it is broken down, the amine group and other products travel to the respective renal organ or liver and finally waste products are formed. So, the source of amine group in waste is amino acid.
2) Fish produces waste as ammonia. Ammonia can also diffuse out of the body through water. As fish lives is water, there is plenty of water supply in surrounding environment. And ammonia is very toxic for the body. So it can easily diffuse out even through the water passing through the gills. This type of organisms (cnidaria, porifera, platyhelminthes) along with fishes are called ammonotelic as they excrete ammonia.
3) Bird and reptile produce uric acid as waste product. They have very little water in their environment. So they cannot excrete ammonia by diffusion. And if that amonia retains in their body it will be fatal for them. So, they evolved in such a way that they can produce uric acid. They are called uricotelic animals. They get very little water. So, they try to conserve water as much as possible. Uric acid is the least toxic material for body. Their waste is formed in a highly concentrated form maybe you can compare with it a solid. By this, they conserve more water from their waste, and use that water in their other biological processess.
4) Land animals like human, produces urea as waste material. These animals are called ureotelic animals. It is less toxic than ammonia and needs little less water than the ammonotelic animals. They drink water as their need. And during excretion, some amount of that water is needed to excrete that waste in form of urea. However, the amount of water here needed is much more than the case of uricotelic animals.
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