Question

Mode of nutrition in Rhizopus is
A. Parasitic
B. Symbiotic
C. Saprophytic
D. Autotrophic

Answer 1

Hint: The different organisms acquire food through different processes. Majorly, organisms are divided into two categories- autotrophs and heterotrophs. The Rhizopus obtains its food from dead and decaying organic matter.

Complete answer:
The correct answer is (C).
Rhizopus stolonifer is an organism that belongs to the kingdom Fungi. They adopt the heterotrophic mode of nutrition i.e they obtain their food from other organisms, they are dependent on others. It is a saprophytic organism because this organism feeds on the dead, damp and decaying material present in the soil. The saprophytic mode of nutrition is considered to be heterotrophic nutrition as they do not prepare their food by themselves. They release enzymes which are responsible for breaking the organic compounds which are present in the dead and decaying matter and convert it into simpler compounds. It is also known as bread mould.
Proteins present are broken into amino acids, lipids are converted into fatty acid and glycerol and starch are converted into glucose. These simpler products are then re-absorbed into the hypha through the cell wall by the process of endocytosis and then this absorbed food is passed on throughout the mycelium complex and it is responsible for growth and development of the rhizopus.
Rhizopus reproduces by the process of spore formation. They develop spores which are present in sporangia. When the favorable condition arrives, the wall of the sporangia bursts and the spores are released and thus give rise to multiple Rhizopuses.

Note: Except saprophytic mode of nutrition, other heterotrophic modes of obtaining nutrition are also seen in the organism like parasitic mode of nutrition which is adopted by cuscuta, venus flytrap etc., holozoic mode of nutrition is seen in humans, animals, etc. and Autotrophic mode of nutrition is well established in plants, cyanobacteria, algae etc.