Test: Mucor & Rhizopus - Class 11 MCQ

Reproduction in Mucor takes place by isogametangia. Mucor reproduce both in sexual and asexual method. While asexual reproduction takes place by the formation of spores, sexual reproduction takes place by conjugation of isogametes. 

The zygospore is hyaline and characteristically with a single, eccentric globule and many diploid nuclei. Meanwhile the zygospore enlarges and secretes a thick wall, which is differentiated into exospore and endospore. The zygospores are usually brown to black; with rough blunt projections or warts.

A zygospore is a diploid reproductive stage in the life cycle of many fungi and protists. When the environment is favorable, the zygospore germinates, meiosis occurs, and haploid vegetative cells are released. In fungi, a sporangium is produced at the end of a sporangiophore that sheds Spores.promycelium. : a short usually 4-celled hyphal filament that constitutes the basidium of various heterobasidiomycetous fungi, is formed by germination of a teliospore in rusts or of a chlamydospore in smuts, and bears sporidia. — called also epibasidium. — compare autobasidium.

Blakeslee made these observations as a result of his studies on zygospore formation in Mucorales. He found that in some species of Rhizopus, zygospores were formed freely while in others like R. nigricans zygospores were formed rarely.

Torula, in its inactive form (usually labeled as torula yeast), is widely used as a flavoring in processed foods and pet foods. It is often grown on wood liquor, a byproduct of paper production, which is rich in wood sugars (Xylose).

A chlamydospore is the thick-walled large resting spore of several kinds of fungi, including Ascomycota such as Candida, Basidiomycota such as Panus, and various Mortierellales species. It is the life-stage which survives in unfavourable conditions, such as dry or hot seasons.

Mucor mucedo uses asexual reproduction. When erect hyphae sporangiophores are formed. The tip of the sporangiophore swells to form a globose sporangia that contains uninucleate, haploid sporangiospores. An extension of the sporangiophore called the columella protrudes into the sporangium.

Puccinia, Penicillium and Alternaria do not produce zygospore. In the zygomycetes, like Mucor, Rhizopus etc., the male (+) and female (-) gametangia fuse and the gametangial copulation leads to the formation of a zygospore. It contains many pairs of nuclei. Some of these pairs of nuclei fuse to produce diploid nuclei, while others degenerate. The diploid nuclei undergo reduction division before the zygospore germinates into stalked sporangium containing numerous haploid sporangiospores.

Each progametangium of Rhizopus undergoes division to form gametangium and suspensor. The two gametangia are in contact with each other. They contain multinucleated protoplasts that behave as aplanogamete or coenogamete. In Zygomycetes (conjugation fungi), the fusing gametes are multinucleate and are called as coenogametes.

When Mucor is allowed to grow in sugar rich solution, its mycelium breaks down in to small, spherical and independent cells. This is called 'torula stage' or 'torula condition' in mucor. When first discovered it was though to be a different fungus altogether and was given the name Torula.Then it was found out that it is just an abnormal condition in Mucor.

Mucor mucedo (genus species) uses asexual reproduction. When erect hyphal sporangiophores are formed.The tip of the sporangiophore swells to form a globose sporangium that contains uninucleate, haploid sporangiospores. Mucor includes both homothallic (self-compatible) and heterothallic species.

Mucor mucedo (genus species) uses asexual reproduction. When erect hyphal sporangiophores are formed.The tip of the sporangiophore swells to form a globose sporangium that contains uninucleate, haploid sporangiospores. An extension of the sporangiophore called the columella protrudes into the sporangium.

Mucor mucedo, commonly known as the common pinmould,is a fungal plant pathogen and member of the phylum Zygomycota and the genus Mucor. Commonly found on soil, dung, water, plants and moist foods, Mucor mucedo is a saprotrophic fungus found world-wide with 85 known strains. It is often mistaken for Rhizopus rots on fruits (i.e. strawberries) due to similar mould growth shape and colour.Contrastingly, however, Mucor mucedo is found to grow on a wide range of stored grains and plants, including cucumber and tomato. Discovered in Italy in 1729 by P.A. Micheli and later noted by Carl Linnaeus in 1753 in the Species Plantarum, Mucor mucedo was originally classified as Mucor vulgaris by Micheli but later classified synonymous under name Mucor mucedo. The species was redescribed as Ascophora mucedo by H.J. Tode in 1790 but this type resided in a stoloniferous habitat and was later made the type of new genus Rhizopus.

In Mucor, the haploid stage is multicellular whereas the diploid stage is limited only to the unicellular zygote. The reduction division or meiosis occurs in zygote.
So the correct answer is option B.

Mucor mucedo (genus species) uses asexual reproduction. When erect hyphal sporangiophores are formed.The tip of the sporangiophore swells to form a globose sporangium that contains uninucleate, haploid sporangiospores.  Mucor includes both homothallic (self-compatible) and heterothallic species.

Rhizopus stolonifer is commonly known as black bread mold. It is a member of Zygomycota and considered the most important species in the genus Rhizopus. It is one of the most common fungi in the world and has a global distribution although it is most commonly found in tropical and subtropical regions.

In mucor sexual reproduction takes place by planogametic copulation. In this process fusion of two gametes of opposite sex or strains (+ and - strains) takes place where one or both of the fusing gametes are motile (flagellated). It results in the formation of a diploid zygote.

Mucor is a mold found in soil, plants, manure, glycogen and oildecaying fruits, vegetables and as a common contaminant of stored and processed foods in the kitchen.

Mucor is a genus of mold. Molds are in the kingdom Fungi, and they are formed from thread-like hyphae that spread out from a visible mycelium. Mucor are often found in soil, and most species grow best at low temperatures. Mucor velutinosus and Mucor ellisoideus both infect humans.

Mucor is a hyphal fungus body structure consists of a fine thin thread like tubular branch colony mass of mycelium. Unit structure of mycelium is hyphae. A hypha is coenocytic.

Mucor mucedo (genus species) uses asexual reproduction. When erect hyphal sporangiophores are formed.The tip of the sporangiophore swells to form a globose sporangium that contains uninucleate, haploid sporangiospores. An extension of the sporangiophore called the columella protrudes into the sporangium.

Isogamy is a form of sexual reproduction that involves gametes of similar morphology (similar shape and size), differing in general only in allele expression in one or more mating-type regions. Because both gametes look alike, they cannot be classified as "male" or "female". Instead, organisms undergoing isogamy are said to have different mating types, most commonly noted as "+" and "−" strains, although in some species of Basidiomycota there are more than two mating types (designated by numbers or letters). In all cases, fertilization occurs when gametes of two different mating types fuse to form a zygote.

If the growth of Mucor is in the average range of 0.4 in refrigerator, it will grow at an average of 23.2 at room temperature. It grows well when the relative humidity is in the range of 95%. Fungus usually prefer shady areas.
Thus, the correct answer is option D.