Question

Which of the following life cycle is associated with mucor?
(a) Haplontic
(b) Diplontic
(c) Isomorphic
(d) Heteromorphic

Answer 1

Mucor is a microbial genus of around 40 species of moulds commonly found in the biosorption process in the soil, digestive systems, plant surfaces, some cheeses such as tomme de savoie, rotting vegetable matter, and iron oxide residue.

Complete answer:
From Mucor sp. It can communicate both methods of sexual and asexual reproduction, and Mucor's somatic body is haploid. Where the process of asexual reproduction occurs with the development of sporangiospores and sporangia. Whereas, during sexual reproduction, the fusion of two haploid nuclei in the gametangia produces a diploid zygospore.
Asexual reproduction is employed by Mucor mucedo (genus species). Upon the development of erect hyphae sporangiophores. To form a globose sporangium that includes uninucleate, haploid sporangiospores, the tip of the sporangiophore swells. A sporangiophore extension called the columella protrudes into the sporangium. To release the spores, which germinate readily to form a new mycelium on suitable substrates, the sporangium walls are easily ruptured.
Compatible strains form short, specialised hyphae, called gametangia, during sexual reproduction. A thick-walled, spherical zygosporangium evolves at the point where two complementary gametangia fuse. Usually, the zygosporangium contains a single zygospore. Within the zygospores, nuclear karyogamy and meiosis (sexual recombination) occur, which are assumed to be long-lived and resistant to adverse conditions. To form hyphae or a sporangium, they can germinate. Both homothallic (self-compatible) and heterothallic organisms include Mucor.

Additional information: Typically, colonies of this fungal genus are white to beige or grey and quick-growing. Colonies on a culture medium can grow to a height of several centimetres. Because of the growth of spores, older colonies become grey to brown in colour.
Mucor spores or sporangiospores may be simple or branched and form apical, globular sporangia that a column-shaped columella supports and elevates. The form and insertion of the columella and the absence of stolons and rhizoids will distinguish Mucor species from moulds of the genera Absidia , Rhizomucor , and Rhizopus. Certain species of Mucor produce chlamydospores. With irregular non-septate hyphae branching at large angles, they form mould.
So, the correct answer is ‘(a) Haplontic’.

Note: Owing to their inability to thrive in warm conditions close to 37 degrees, most species of 'Mucor' are unable to infect humans and endothermic animals. Thermotolerant species such as Mucor indicus often cause necrotizing infections known as zygomycosis, which are opportunistic, and sometimes rapidly spread.