NIOS Class 12 Biology — Flashcards for Quick Revision

A: Kingdom Monera includes all bacteria and cyanobacteria. Key characteristics: (1) Prokaryotic organisms - lack a true nucleus with nuclear membrane; (2) Unicellular, though some are multicellular and f

A: Peptidoglycan is a unique chemical compound found exclusively in bacterial cell walls. Its significance includes: (1) It is a complex polymer made of polysaccharides and amino acids; (2) It provides s

A: Both are appendages that project from the bacterial cell wall, but serve different purposes: PILI: (1) Short, thin, thread-like tubular structures; (2) Help bacteria attach to surfaces and other cells

A: Kingdom Plantae consists of multicellular, eukaryotic organisms that are photosynthetic autotrophs (rarely heterotrophs) with cellulosic cell walls. All plants are embryophytes, meaning they develop f

A: Bryophytes are the 'amphibians of the plant kingdom' because they complete their life cycle in both aquatic and terrestrial environments. They include liverworts, mosses, and hornworts. Ecologically,

A: Rhizoids are hair-like structures that anchor bryophytes to soil and absorb water and minerals from the substrate. In liverworts and hornworts, rhizoids are unicellular, while in mosses they are multi

A: Cell theory was proposed by M.J. Schleiden and Theodore Schwann in 1838. It states three fundamental principles: (1) All organisms are composed of cells, (2) The cell is the structural and functional

A: Prokaryotic cells (bacteria) and eukaryotic cells (animals, plants, fungi) differ in: (1) Nucleus: Prokaryotes lack a defined nucleus; DNA is in a nucleoid region. Eukaryotes have a membrane-bound nuc

A: The plasma membrane (also called cell membrane) is a living, selective boundary that encloses the cell. The Fluid Mosaic Model, proposed by Singer and Nicholson (1972), best explains its structure. Ac