All Free Biology MCQs with Answers

• A. Pseudopollination
• B. Pseudoparthenocarpy
• C. Mimicry
• D. Pseudocopulation

Explanation: In an orchid Ophrys speculum, there is most interesting and unique mechanism of pollination.

• A. Tetraploid
• B. Pentaploid
• C. Haploid
• D. Triploid

Explanation: If the female plant is tetraploid, then the central cell of the embryo sac, which is a fused polar nucleus, will also be tetraploid.

• A. Development of anthers
• B. Opening of flower bud
• C. Stigma receptors
• D. Formation of Pollen:

Explanation: Anthesis is the process of opening floral buds. The reception of pollen by stigma is called pollination.

• A. Autogamy
• B. Geitonogamy
• C. Xenogamy
• D. Allogamy

Explanation: Geitonogamy is the transfer of pollen grains from the anther to stigma of another flower on the same plant or genetically similar plant…

• A. 200/400
• B. 400/800
• C. 300/600
• D. 250/500

Explanation: Number of meiotic divisions required to produce 200/400 seeds of pea would be 250/500.

• A. Orthotropous
• B. Anatropous
• C. Campylotropous
• D. Amphitropous

Explanation: In hemianatropous or hemitropous ovule, the nucellus and integuments are at right angles to stalk or funiculus so that the ovule becomes…

• A. Apomixis
• B. Embryology
• C. Embryogeny
• D. Cytology

Explanation: Study of formation, growth and development of new individual from an egg is embryology.

• A. Fusion of gametes
• B. Fusion of cytoplasms
• C. Fusion of two similar spores
• D. Fusion of two dissimilar spores

Explanation: Syngamy means fusion of gametes. Syngamy is the phenomenon in which male gamete fuses with an egg.

• A. Nucellus
• B. Embryo sac
• C. Micropyle
• D. Pollen grain

Explanation: Pollen grain is odd one among all the other three. Pollen grain is a male gametophytic structure whereas all the other three are found…

• A. Nucellus and antipodal cells
• B. Antipodal cells and egg cell
• C. Antipodal cells and megaspore mother cell
• D. Nucellus and primary endosperm nucleus

Explanation: Antipodal cells and egg cell are haploid structures as they are formed after meiosis while the others nucellus, megaspore mother cell and…

• A. Embryo
• B. Axis part of embryo
• C. Ovule
• D. Endosperm

Explanation: Embryo sac occurs in ovule. Ovule is integumented megasporangium. It consists of nucleus covered by one or two integuments, mounted on a…

• A. Bryophytes and angiosperms
• B. Pteridophytes and angiosperms
• C. Angiosperms and gymnosperms
• D. Angiosperms and fungi

Explanation: The term pollination refers to the transfer of pollen from anther to stigma.

• A. Chalazogamy
• B. Mesogamy
• C. Porogamy
• D. Pseudogamy

Explanation: In most of the plants the pollen tube enters the ovule through the micropyle and the phenomenon is called as porogamy.

• A. Base pairing of their DNA and RNA
• B. Formation of hydrogen bonds
• C. Mutual attraction due to differences in electrical charges
• D. Attraction of their protoplasts

Explanation: The two gametes i.e., sperm released by pollen tube and egg move in opposite direction by an unknown mechanism but most probably by…

• A. Ovule
• B. Megaspore mother cell
• C. Embryo sac
• D. Nucellus

Explanation: Female gametophyte of angiosperms is represented by embryo sac. The polygonum type of embryo sac contains 8­nuclei and 7­cells.

• A. Microsporangium
• B. Nucellus
• C. Microspore
• D. Stamen.

Explanation: Male gametophyte of angiosperms is a microspore. Microspore is haploid, uninucleate, minute spores produced in large numbers as a result…

• A. Anther wall
• B. Tapetal layer of anther wall
• C. Connective tissue
• D. Young pollen grains

Explanation: Young pollen grains produce androgenic haploids in anther cultures. Because rest all i.e., anther wall, tapetal layer of anther wall and…

• A. Gametes are invariably haploid
• B. Spores are invariably haploid
• C. Gametes are generally haploid
• D. Both spores and gametes are invariably haploid

Explanation: Gametes are invariably haploid. Spores are formed in lower plants by mitotic division and they may be diploid but gametes are always be…

• A. Vegetative cell is not damaged.
• B. Contents of killed generative cell stimulate pollen growth
• C. Laser beam stimulates growth of pollen tube
• D. The region of emergence of pollen tube is not harmed

Explanation: Generative cell was destroyed by laser but a normal pollen tube was still formed because vegetative cell is not damaged.

• A. Amphimictic haploid
• B. Amphimictic diploid
• C. Apomictic haploid
• D. Apomictic diploid

Explanation: Nucellar embryo is apomictic diploid. Substitution of usual sexual reproduction by a form of reproduction which does not include meiosis…