Botany MCQs for NEET — Practice Questions with Answers

Chlorenchyma or assimilatory parenchyma are parenchymatous cells that posses abundant chloroplasts in them. They are capable of photosynthesis. A spore capsule of moss can perform photosynthesis because of the presence of chlorenchyma cells in them.

Sexual reproduction in Spirogyra takes place by the process of conjugation. In Spirogyra, the process of conjugation may be of two types - scalariform conjugation and lateral conjugation. Scalariform conjugation occurs in heterothallic species. Lateral conjugation occurs between the adjacent cells of the same filament of homothallic species of Spirogyra. Lateral conjugation are of two types. They are indirect lateral conjugation (chain type) and direct lateral conjugation.

In mosses the sporophytes (i.e., the diploid body) are short-lived and dependent on the gametophyte. In the presence of water, sperms from the antheridia swim to the archegonia and fertilization occurs, leading to the production of a diploid sporophyte. The sperm of mosses is biflagllate, i.e., they have two flagella that aid in propulsion. Since the sperms must swim to the archegonium, fertilization cannot occur without water.

Endosperm is the food laden tissue which is meant for nourishing the embryo in seed plants. In gymnosperms, it represents the female gametophyte and thus is haploid (n). In angiosperms, the endosperm is a special tissue which is formed as a result of fusion of a male gamete with diploid secondary nucleus of the central cell (vegetative fertilization or triple fusion). The fusion product is primary endosperm cell having a triploid (3n) endosperm nucleus.

In pteridophytes, majority of plants are homosporous (producing similar kind of spores) e.g., Lycopodium. However, plants of genera like Selaginella and Salvinia are heterosporous (producing macro and micro spores). Pinus and Cycas, which are gymnosperms, are also heterosporous.

Roots in Cycas are of two types - normal and coralloid roots. Coralloid roots are irregular, negatively geotropic, dichotomously branched coral like roots which do not possess root hair and root caps. Coralloid roots have a symbiotic association with blue-green algae like Nostoc and Anabaena species.

Alginic acid (or algin or alginate) is an anionic polysaccaride distributed widely in the cell walls of many brown algae (Phaeophyceae). It is a phycocolloid which is obtained commercially from Laminaria, Macrocystis, Nereocystis, Fucus, Sargassum etc.

Genera like Selaginella and Salvinia which produce two kinds of spores, macro (large) and micro (small) spores, are known as heterosporous pteridophytes Lycopodium and Equisetum are homosporous pteridophytes. i.e., they produce only one type of spores.

Pteridophytes, may produce similar spores (homosporous) or dissimilar spores (heterosporous). Selaginella and Salvinia show heterospory.