All Free Biology MCQs with Answers

1641. Simple breaking of mycelium resulting in formation of a new mycelium from each broken segments is called__________?

• A. Sporing
• B. Conidiation
• C. Budding
• D. Fragmentation

Explanation: Fragmentation is the asexual reproduction method in which a mycelium breaks into pieces and each viable piece grows into a new mycelium. Conidiation and sporing involve specialized spores, while budding forms a smaller outgrowth, so students may choose a by treating every fungal asexual method as spore formation.

1642. Constricting ring around nematode is formed by_____________?

• A. Arthrobotrys
• B. Pleurotus ostreatus
• C. Mildews
• D. All of these

Explanation: Arthrobotrys is a predatory fungus that forms constricting adhesive rings around nematodes; the rings tighten when a nematode enters and help the fungus capture it. Pleurotus can trap nematodes with toxin-producing structures but does not form these characteristic constricting rings, so students may choose d by grouping all nematode-trapping fungi together.

1643. By which of the following mechanism unicellular yeast reproduce?

• A. Sporing
• B. Conidiation
• C. Budding
• D. Fragmentation

Explanation: Yeast is a unicellular fungus that commonly reproduces asexually by forming a small outgrowth called a bud, which enlarges and separates from the parent cell. The likely alternative is sporing, but spore formation is not the usual method of reproduction in unicellular yeast.

1644. Parasitic fungi absorb nutrients directly from the living host cytoplasm with the help of special hyphal tips called___________?

• A. Mildew
• B. Constricting ring
• C. Haustoria
• D. All of these

Explanation: Haustoria are specialized hyphal projections that enter or grow against host cells and absorb nutrients from living plant tissue. Students may choose mildew because it is associated with parasitic fungi, but mildew is a fungal growth or disease, not a nutrient-absorbing hyphal tip.

1645. Unicellular fungi which is non-hyphal is___________?

• A. Mushroom
• B. Yeast
• C. Penicillium
• D. Mold

Explanation: Yeast is a unicellular fungus whose body consists of individual cells rather than a network of elongated hyphae. Mushroom may seem plausible because it is also a fungus, but mushrooms are multicellular and produce a visible hyphal fruiting body.

1646. In which of the following example of fungi dikaryotic hyphae exist for long period?

• A. Deuteromycota
• B. Basidiomycota
• C. Zygomycota
• D. All of these

Explanation: Basidiomycota commonly maintain dikaryotic hyphae, in which each cell contains two genetically different haploid nuclei, for a prolonged part of the life cycle. Deuteromycota is often selected because it includes many familiar molds, but its fungi do not characteristically maintain a long dikaryotic phase.

1647. Coenocytic hyphae are also known as______________?

• A. Septate
• B. Perforated hyphae
• C. Aseptate
• D. Uninucleate hyphae

Explanation: Coenocytic hyphae lack cross-walls or septa, so they form a continuous multinucleate tube and are therefore called aseptate hyphae. Septate hyphae are the opposite condition because they are divided by internal cross-walls.

1648. Which of the following is called black bread mold?

• A. Pilobolus
• B. Penicillium
• C. Neurospora
• D. Rhizopus

Explanation: Rhizopus is commonly called black bread mold because it produces black sporangia on decaying bread and other organic material. Penicillium may be chosen because it is another common bread mold, but its colonies are typically blue-green and its spores are borne in brush-like conidiophores.

1649. Ecological role of fungi as decomposers is only paralleled by_____________?

• A. Cyanobacteria
• B. Blue green algae
• C. Bacteria
• D. Virus

Explanation: Bacteria, like fungi, are major decomposers that secrete enzymes into dead material and absorb the soluble products, returning nutrients to ecosystems. Cyanobacteria or blue-green algae are mainly photosynthetic producers, while viruses do not function as decomposers.

1650. At which stage in the life cycle of Rhizopus meiosis takes place?

• A. Formation of sporangiophore via germination of zygospore.
• B. Formation of spores in sporangia
• C. Fusion of two hyphae
• D. Formation of Zygote by fusion of gametangia.

Explanation: In Rhizopus, the zygospore is diploid and undergoes meiosis when it germinates, producing haploid spores in a newly formed sporangium. Fusion of hyphae and gametangia occurs before the diploid zygospore stage, so choosing either fusion option confuses fertilization with meiosis.