Question

A guanotelic animal is
A. Anopheles
B. Spider
C. Earthworm
D. Prawn

Answer 1

Hint: Every organism has its specific way to excrete a particular excretory product. Animals that excrete guanine as their waste product are called guanotelic. Mostly Arachnids are animals that are guanotelic. These animals are adapted to live in arid areas.

Complete answer: Guanotelic animals are characterized by their excretory product guanine. Guanine is a purine nucleotide base that resembles uric acid by its cyclic ring structure. Also, guanine has similar atoms in its ring structure to uric acid. It is insoluble in water and hence it does not require water for excretion. This is the reason that guanotelic animals are adapted to arid regions where there is scanty water. Guanine like uric acid is non-toxic and is excreted in solid form. In uricotelic animals that excrete uric acid, guanine is formed as an intermediate. In guanotelic animals, the inosinic acid pathway for excretion terminates in guanine formation. Arachnids like scorpions and spiders excrete their waste product in the form of guanine. Hence, they are said to be guanotelic.
Let us study other options also.
-Anopheles is a mosquito species found proliferating warmer and humid conditions. These are famous for their potential to spread malaria parasites to humans. These are uricotelic animals.
-The earthworm is an invertebrate soft-bodied animal usually found crawling in soils. They have a cylindrical body and excrete in the form of nitrogenous wastes like urea, ammonia, uric acid, etc. their excretory product has a special name that is castings. It is used as organic compost.
-Prawns excrete through green glands. The excretory product is a nitrogenous waste.
Hence, from the above discussion, we can conclude that the right answer is option B, i.e., Spider.

Note: Lack of certain enzymes involved in uric acid excretion is offered as a possible reason that guanotelic animals excrete guanine. Guanine is the only purine detected in chromatographic tests of excreta obtained from many species of spiders. Amino acids and urea are not present in the excreta of spiders.