Question

read the passage about the history of cell theory
today, we know that all living things are made of
cells. but it wasnt until the invention of the
compound microscope that cells and microscopic life
could be observed. cell theory, now considered a
unifying principle of biology, developed over the
course of many years through the contributions of
numerous scientists.
robert hooke, an english physicist and microscopist,
first described the cell in 1665. hooke used a
compound microscope to examine cork. what he saw
were many small adjoining rooms that looked like
the cells that monks occupied within monasteries.
hooke was actually observing the cell walls within
cork tissue.
shortly after hooke published his observations in his
book micrographia, a dutch scientist and microscope
maker named antonie van leeuwenhoek observed
moving particles through his single - lens microscope.
he assumed that because they could move, these
particles must be alive, and he called them animalcules. these particles were, in fact,
microorganisms. leeuwenhoek is credited as the first to discover and describe
microorganisms like bacteria and protists, and he later became known as the father of
microbiology.
over the next two centuries, many scientists studied and contributed to the
understanding of cells, their structure, and their function. in the 1830s, after years of
studying plants, german scientist matthias schleiden concluded that every structural
aspect of a plant is composed of cells or their products. his friend and fellow german
scientist, theodor schwann, reached an analogous conclusion about animals and animal
cells shortly thereafter. because animal cells lack cell walls, they were difficult to identify;
it was not obvious that they would be as essential to animal tissue as plant cells are to
plant tissue. but schwann made a convincing argument for similarities in animal and
plant cell structure. together, schleidens and schwanns conclusions comprise the first
two tenets of cell theory: all organisms are made of one or more cells, and cells are the
smallest unit of structure and function for organisms.
however, schleiden and schwann did not yet understand cell growth. for some time,
they hypothesized that new cells crystallized from the material within or between other
existing cells. as cell research continued, the scientific community showed that cells form
from preexisting cells - the third tenet of cell theory. in 1851, robert remak proposed
that cell division is the universal method of cell formation. german pathologist rudolf
virchow popularized this idea in 1855 with the latin phrase omnis cellula e cellula, which
translates to every cell from a cell.
the discovery of the cell and the development of cell theory laid the groundwork for
pioneering discoveries across all fields of biology, from genetics to ecology. today,
scientists all over the world are still uncovering exciting insights into the structure and
function of cells and their parts.
match the scientists to their contributions toward cell theory.
hooke leeuwenhoek virchow
schleiden remak schwann
contribution to cell theory scientist
proposed that cell division is the universal method of cell
formation.
first observed and described single - celled organisms.
determined that all animal tissues are composed of cells.
determined that all plant tissues are composed of cells.
popularized the idea that new cells arise from preexisting
cells.
first described and named cells.

Explanation:

• Robert Remak: Proposed that cell division is the universal method of cell formation.
• Antonie van Leeuwenhoek: First observed and described single - celled organisms.
• Theodor Schwann: Concluded that all animal tissues are composed of cells.
• Matthias Schleiden: Concluded that all plant tissues are composed of cells.
• Rudolf Virchow: Popularized the idea that new cells arise from pre - existing cells.
• Robert Hooke: First described and named cells.

Answer:

• Proposed that cell division is the universal method of cell formation: Robert Remak
• First observed and described single - celled organisms: Antonie van Leeuwenhoek
• Concluded that all animal tissues are composed of cells: Theodor Schwann
• Concluded that all plant tissues are composed of cells: Matthias Schleiden
• Popularized the idea that new cells arise from pre - existing cells: Rudolf Virchow
• First described and named cells: Robert Hooke