Q.Which of the following is the single most fundamental structural feature that distinguishes a prokaryotic cell from a eukaryotic cell?

All cellular life is organised on one of two structural plans. Prokaryotic cells (bacteria, cyanobacteria, mycoplasma) have no true, membrane-bound nucleus -- their DNA lies as a nucleoid in direct contact with the cytoplasm -- and entirely lack membrane-bound organelles; they contain smaller 70S ribosomes and are typically 1-10 micrometres across, dividing by binary fission. Eukaryotic cells (protists, fungi, plants, animals) possess a true nucleus enclosed by a double nuclear envelope, a full set of membrane-bound organelles, larger 80S cytoplasmic ribosomes (though their mitochondria and plastids still carry 70S ribosomes), are typically 5-100 micrometres across, and divide by mitosis or meiosis. Both types share a plasma membrane, cytoplasm and genetic material as the common baseline of what makes a cell a cell.