All Free Biology MCQs with Answers

• A. Endophytic Fungi
• B. Mycorrhizal fungi
• C. Ergot
• D. Rhodotorula

Explanation: Mycorrhizal fungi are more directly linked to sol fertility.

• A. Aspergillus flavus
• B. Candida albicans
• C. Agaricus bisporus
• D. Histoplasma capsulatum

Explanation: The common button mushroom is scientifically named Agaricus campestris.

• A. Orange-yellow colored disease spots on their host surface
• B. Dusty spore masses that resemble soot
• C. Rust fungi have fruiting bodies
• D. Puccinia species

Explanation: Rust fungi produce orange-yellow, powdery lesions on infected plant surfaces that resemble rusted iron, which is why they are commonly…

• A. Bacteria
• B. Virus
• C. Fungus
• D. Arthropod

Explanation: Athlete's foot is an infection of the feet caused by fungus. The medical term is tinea pedis or ringworm of the foot.

• A. Trichinella spiralis
• B. Ascaris lumbricoides
• C. Ancylostoma duodenale
• D. Enterobius vermicularis

Explanation: Trichinella spiralis is a nematode parasite, occurring in rodents, pigs, horse, bears and humans, and is responsible for the disease…

• A. Sarcomeres
• B. Candidiasis
• C. Lovastatin
• D. Aspergillus

Explanation: Excess growth of Candida fungus in the mouth causes a condition known as "Oral thrush" or "Oral Candidiasis".

• 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…

• 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

• 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…

• 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…

• 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…

• 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…

• 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.

• 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.

• 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.

• 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…

• A. They are thalloid
• B. They possess archegonia
• C. They contain chloroplast
• D. All of these

Explanation: Bryophytes are thalloid, contain chloroplasts, and have archegonia for sexual reproduction.

• A. Water is essential for their vegetative propagation
• B. The sperms can easily reach up to egg in the archegonium
• C. Archegonium has to remain filled with water for fertilization
• D. Water is essential for fertilization for their homosporous nature

Explanation: Water helps motile sperms swim to reach the egg in archegonium for fertilization.

• A. Possess archegonia
• B. Contain chloroplast
• C. Have thalloid forms
• D. Have no conducting tissue

Explanation: Bryophytes have true multicellular sex organs like archegonia, unlike algae.

• A. Exocarp
• B. Mesocarp
• C. Endocarp
• D. Mesocarp & endocarp

Explanation: The juicy hair-like structures in lemon are formed from the endocarp, which contains juice-filled cells.