Free Biodiversity and Variety of Life MCQs with Answers

2781. Alcoholic fermentation is the sole mean of respiration in:

• A. Saccharomyces
• B. Armillaria
• C. Trichonympha
• D. Balanitidium

Explanation: Alcoholic fermentation occurs in yeast and plants. Alcoholic fermentation is the sole mean of respiration in Saccharomyces cerevisiae (yeast). Saccharomyces can ferment carbohydrates, breaking down glucose to form ethanol and carbon dioxide.

2782. Nuclear mitosis occurs in

• A. Plants
• B. Animals
• C. Fungi
• D. Monrea

Explanation: Plants and Animals undergo regular mitosis, Monera reproduce asexually by binary fission while fungi undergo nuclear mitosis

2783. "Yeast" reproduces by:

• A. Spores
• B. Conidia
• C. Fragmentation
• D. Budding
• E. Nuclear fusion

Explanation: Yeast reproduces primarily through a process called budding, which is a form of asexual reproduction.In budding, a small bud or outgrowth forms on the parent yeast cell. The bud gradually enlarges in size and eventually detaches from the parent cell, becoming a separate individual yeast cell. This process is similar to how a bud grows on a plant and eventually becomes a new plant

2784. Characteristic mitosis present in fungi is "nuclear-mitosis" during which:

• A. The nuclear membrane breaks, and the spindle is formed outside the nucleus
• B. The nuclear membrane breaks, and the spindle is formed within the nucleus
• C. The nuclear membrane doesn't break, and the spindle is formed outside the nucleus
• D. The nuclear membrane doesn't break, and the spindle is formed within the nucleus

Explanation: "In fungi, including both yeasts and filamentous fungi, the characteristic mitosis is referred to as "closed mitosis" or "nuclear mitosis." During nuclear mitosis, the nuclear envelope or membrane remains intact, and the spindle apparatus forms within the nucleus. ".

2785. Fungi that obtain their food directly from dead organic matter are called:

• A. Autotrophs
• B. Heterotrophs
• C. Saprotrophs
• D. Chemotrophs
• E. Mutualists

Explanation: the correct option is "saprotrophs." Saprotrophs are organisms, including fungi, that obtain their nutrients by decomposing and absorbing organic matter from dead organisms or decaying organic material. Fungi that specialize in this mode of nutrition are often involved in the decomposition of dead plant and animal matter, helping to recycle nutrients back into the ecosystem.

2786. Fungi that can grow only on their living host and cannot be grown on available defined growth culture medium are called:

• A. Autotrophs
• B. Saprotrophs
• C. Obligate Parasites
• D. Facultative Parasites
• E. Predators

Explanation: the correct option is "obligate parasites" because they are the only ones among the given options that can only grow on their living host and cannot be cultivated on available defined growth culture media. Obligate parasites have evolved specific adaptations to exploit and rely entirely on their host organisms for their growth, reproduction, and nutrition.

2787. Which one of the following statements is wrong?

• A. Algae increase the level of dissolved oxygen in the immediate environment.
• B. Algin is obtained from red algae and carrageenan from brown algae.
• C. Agar­agar is obtained from Gelidium and Gracilaria
• D. Laminaria and Sargassum are used as food

Explanation: (b) : Alginic acid is obtained from brown algae whereas carrageenan is obtained from red algae.

2788. Which one of the following statements is wrong?

• A. Chlorella and Spirulina are used as space food
• B. Mannitol is stored food in Rhodophyceae
• C. Algin and carrageenan are products of algae
• D. Agar­agar is obtained from Gelidium and Gracilaria

Explanation: (b) : Laminarin and mannitol are food reserves of brown algae or Phaeophyceae. Rhodophycean algae store food in the form of floridean starch.

2789. Select the wrong statement:

• A. In Oomycetes, the female gamete is smaller and motile, while the male gamete is larger and non­motile.
• B. Chlamydomonas exhibits both isogamy and anisogamy and Fucus shows oogamy.
• C. Isogametes are similar in structure, function and behaviour
• D. Anisogametes differ either in structure, function, or behavior.

Explanation: . (a ): In oomycetes, like other oogamous organisms female gamete is large and non­ motile, while male gamete is small and motile.

2790. Which one of the following statements is correct?

• A. The seed in grasses is not endospermic
• B. Mango is a parthenocarpic fruit
• C. A proteinaceous aleurone layer is present in maize grain.
• D. A sterile pistil is called a staminode

Explanation: (c) : Grass seeds are endospermic. Mango is a seeded fruit. A sterile pistil is called pistillode and a sterile stamen is called staminode. Maize grains consist of fruit wall, seed coat, endosperm, and embryo. The endosperm occupies most of the interior of the grain and consists of two parts, hornyaleurone layer and mainly the storage layers. The aleurone layer lies immediately below the grain covering and is 1­3 cell thick. Aleurone cells are thick-walled with cytoplasm filled with aleurone grains which produce enzymes during seed germination to mobilize stored nutrients.