Botany MCQs for NEET — Practice Questions with Answers

True or rigid cell wall is absent in mycoplasma, but their cytoplasm is surrounded by a tri-laminar (triple layered), highly elastic cell membrane of about 10 nm in thickness.

Morels and truffles are edible fungi that are highly prized for their flavor and aroma. They are not poisonous mushrooms. Penicillium is a multicellular fungus that produces antibiotics, Neurospora is used in biochemical genetics studies, and yeast is a unicellular fungus used in fermentation.

Chrysophytes are placed under the kingdom-Protista. This group includes diatoms and golden algae (desmids). Most of them are photosynthetic. In diatoms, the cell walls form two thin overlapping shells, which fit together as in a soap box.

Nuclear membrane is absent in Monera (bacteria). Monera belongs to the prokaryotic kingdom, which lacks a true nucleus bound by a nuclear membrane. The genetic material in bacteria is present as a single circular DNA molecule in the cytoplasm.

Archaebacteria are likely to be present in deep sea water due to their ability to thrive in extreme environments. They are a group of prokaryotic organisms distinct from bacteria, found in diverse habitats like hot springs, salt marshes, and deep ocean floors.

The enzyme lysozyme is used to convert the rod-shaped cells of Bacillus megatarium to spherical protoplasts by breaking down the peptidoglycan layer of the bacterial cell wall, resulting in the loss of the characteristic rod shape.

Ribosome are the particle of ribonucleoprotein, which is the site of translation of mRNA into protein during protein synthesis. Both prokaryotes and eukaryotes have ribosomes but prokaryotic ribosomes are smaller than the eukaryotic ribosomes and are assembled from different RNA and protein molecules. Prokaryotes have only one type of RNA i.e., 70s type while the eukaryotic ribosomes are of two types i.e., 70s type and 80s. Centrosome, peroxisomes and glyoxisomes are the cell organelles present in eukaryotic cells.

Protista kingdom was created by Haeckel (1886). It includes all unicellular and colonial eukaryotes except those of green and red algae. Protists were the first eukaryotes to evolve about 1000 million years back. They are mostly aquatic. They are broadly divided into three groups - photosynthetic, slime moulds and protozoans. Photosynthetic protists are photoautotrophic like diatoms, dinoflagellates and euglenoids. Protozoan protists include sarcodines/amoebae, zooflagellates, sporozoans and ciliates. It does not include bacteria. Bacteria are simple prokaryotes, occurring in soil, water and air and as symbionts, parasites and pathogens of animals, plants and other micro-organisms.

Lichens represent an unique example of mutualism between algae and fungi. In these plants algae (phycobionts ) and fungi (mycobionts) live together in such a way that they appear as one organism. On the basis of type of thallus the lichens are divided into three type–

(i) Crustose or crustaceous: They occur as thin or thick crust over rocks, soil, tree barks etc.

(ii) Foliose or foliaceous: These are leaf like lichens, which attach to the substratum by means of special rhizoid like organs developed from lower side of thallus.

(iii) Fruticose or filamentous: Cylindrical, flat or ribbon like, branched structures attached to the substratum by their basal ends. They are shrubby lichens.