Botany MCQs for NEET — Practice Questions with Answers

In angiosperms (dicots) the Polygonum type of embryosac is most common. In this embryosac, the arrangement of the nuclei is 3+2+3 i.e., 3 in antipodal cells, 2 as polar nuclei (which later fuse and form a diploid secondary nucleus); and 3 in egg appratus (2 in synergids and 1 in egg cell).

Both event microsporogenesis and megasporogenesis involve the process of meiosis which results in the formation of haploid gametes from the microspore or megaspore mother cells. 

Cucumber is a member of the family-Cucurbitaceae. In the members of this family, the flower are unisexual with male and female flowers on different plants (dioecious) or on the same plant(monoecious).

The coconut water fom tender coconut that we are familiar with, is nothing but free nuclear endosperm (made up of thousands of nuclei) and the surrounding white kemel is the cellular endosperm. In the most common type of endosperm development, the Primary Endosperm Nucleus (PEN) undergoes successive nuclear divisions to give rise to free nuclei. This stage of endosperm development is called free-nuclear endosperm.

Parthenocarpy is a process of developing fruits without involving fertilisation/seed formation. Therefore, the seedless varieties of economically important fruits like orange, banana, watermelon, lemon, etc. are produced using this technique. This technique involves inducing fruit formation by the application of plant growth hormones such as auxins.

(d) Honey is made by bees by nectar and pollens. Bees collect pollen and nectar in the spring when most flowers and plants are in bloom. They collect them in their stomach about an hour, the nector mixes with the proteins and enzymes produced by bees, which convert nectar into honey.

(c) In some seeds like black pepper and beet, remnants of nucellus are also persistent this persistent nucellus is called perisperm. The cells of endosperm tissue are filled with reserve food materials and are used for the nutrition of the developing embryo. The main difference is perisperm is present in seeds and endosperm is present in developing embryo as its reserved food which is completely consumed by is during development

In majority of angiosperms, the pollen grains are shed from the anther at the bicelled (2-celled) stage. But in some genera (both the monocots and dicots), the generative cell divides prior to the dehiscence of the anther and pollen grain is shed at 3-celled stage. Approximately 70% species shed their pollen at the 2-celled stage and 30% at 3-celled stage. 

Apogamy is the formation of a sporophyte from a gametophyte by asexual means such as budding, rather than by sexual fertilization. Sporogenesis is the production or formation of spores. Apospory is the formation of a gametophyte from a sporophyte by asexual means without meiosis or spore formation. Gametogenesis is the development and maturation of sex cells through meiosis.

MMC (Microspore mother cells) are diploid cells derived form the sporogeneous tissue of the anther which undergo meiosis to form tetrads of haploid microsprores which further mature to form pollen grains.