Cell Theory & Overview — NEET Biology MCQs with Solutions

Solution: Virchow added "Omnis cellula-e cellula" — every cell comes from a pre-existing cell.

Solution: Robert Hooke (1665) observed dead cork cells; Leeuwenhoek first saw living cells.

Solution: Robert Brown (1831) discovered the nucleus.

Solution: Mature mammalian RBCs and phloem sieve tubes are enucleate yet living — apparent exceptions handled by cell theory.

Solution: Cells vary greatly in size and shape according to function — bacteria are ~µm, nerve cells can be very long.

Solution: A cell is the smallest unit capable of independent existence; sub-cellular fragments cannot live on their own.

Solution: Cell theory holds that all life is made of cells and all cells arise from pre-existing cells; viruses, being acellular and reproducing only inside a host, do not fit and are regarded as an exception.

Solution: Leeuwenhoek first observed and described living cells (microorganisms). Hooke named cells in cork, Virchow proposed omnis cellula-e cellula, and Robert Brown described the nucleus.

Solution: Rudolf Virchow explained that cells divide and new cells form from pre-existing cells, extending the Schleiden-Schwann proposal.

Solution: Mycoplasmas (~0.3 μm) are the smallest cells and are also wall-less anaerobes — both statements are true, but being wall-less/anaerobic does not cause the small size, so R is not the explanation of A.

Solution: Schleiden (a botanist) concluded plants are made of cells; Schwann studied animal cells and (with Schleiden) framed the theory that the cell wall is a unique animal-cell feature — the mismatched options belong to Hooke, Leeuwenhoek and Virchow respectively.

Solution: As a cell enlarges, volume rises faster than surface area, so the smallest cell has the greatest surface-area-to-volume ratio — a key limit on cell size for efficient exchange.

Solution: Metabolic energy flow occurs throughout the cell (cytoplasm, mitochondria, chloroplasts, etc.), not only in the nucleus; the other three are valid tenets of the cell theory.

Solution: Unicellular organisms ARE capable of independent existence and of performing all essential functions of life, so 'not capable of' applies to none of these.

Solution: Anton von Leeuwenhoek first saw and described a live cell.

Solution: Schwann, studying animal cells, concluded that the cell wall is a unique structure of plant cells.

Solution: The cell theory was formulated jointly by Schleiden and Schwann.

Solution: The plasma membrane statement is not part of the cell theory, which states that organisms are made of cells and products of cells and that all cells arise from pre-existing cells.

Solution: A typical plant cell has a cell wall externally and a plasma membrane internally.

Solution: The nucleus contains chromosomes, which carry genes made of DNA.

Solution: Schwann, a zoologist, studied animal cells, described the thin boundary layer, and concluded the cell wall is unique to plants.

Solution: Their theory did not explain how new cells originate, which Virchow later addressed.

Solution: Rudolf Virchow proposed 'Omnis cellula e cellula', that all cells arise from pre-existing cells.

Solution: Matthias Schleiden was the German botanist who studied plants and their cellular tissues.

Solution: Schleiden and Schwann together proposed that bodies of plants and animals are composed of cells and products of cells.

Solution: Schleiden reported in 1838 and Schwann in 1839.

Solution: Virchow modified the hypothesis by explaining that cells arise from pre-existing cells, finalizing the cell theory.

Solution: Bacteria are typically 3 to 5 μm in length.

Solution: Neurons (nerve cells) are the longest cells in the human body.

Solution: Nerve cells are branched and long, not simply 'long and narrow', making this pairing incorrect.