Video Transcript
Which of the following is the correct sequence of events for the development of cell
theory? (A) Manufacturing and using simple microscopes, determining that plants are comprised
of cells, determining that all living organisms are comprised of cells,
understanding that new cells are produced by preexisting cells. (B) Manufacturing and using simple microscopes, understanding that new cells are
produced by preexisting cells, determining that plants are comprised of cells,
determining that all living organisms are comprised of cells. (C) Manufacturing and using simple microscopes, determining that all living organisms
are comprised of cells, determining that plants are comprised of cells,
understanding that new cells are produced by preexisting cells. (D) Determining that plants are comprised of cells, determining that all living
organisms are comprised of cells, manufacturing and using simple microscopes,
understanding that new cells are produced by preexisting cells.
This question asks us about cell theory. Let’s look at what cell theory is and explain the sequence of events that led to its
development. But first, let’s remove these answer choices so we have more room to work with.
Cell theory is made up of three principles or postulates. The first is that all living things are made up of at least one cell. The second is that the cell is the basic unit of life. And the third principle of cell theory is that all cells come from preexisting
cells. Now let’s look at a timeline that outlines the development of cell theory over the
years and the important contributions made by scientists.
Cells are too small to be visible by eye. So the first thing that had to happen before anyone could start to think about cells
and develop a theory about them was to develop a microscope that was able to magnify
these small objects. This happened in the late 1500s.
Almost a lifetime later, a man named Robert Hooke worked with compound
microscopes. When observing cork slices under his microscope, he noticed that the cork was made up
of tiny structures and filled with regular open spaces which he named cells.
Only 10 years later, Antonie van Leeuwenhoek used his own simple microscopes to
observe many different types of living cells in pond water. Due to his contributions, he is known as the father of microbiology. Van Leeuwenhoek was uneducated. But Robert Hooke was able to reproduce and confirm his findings, which gave van
Leeuwenhoek credibility. Nothing happened after these observations for some time, until Matthias Schleiden
used microscopes to observe plants and discover that plants are made up of cells,
just like Hooke’s cork was.
Schleiden collaborated with another scientist named Theodor Schwann who made
observations about animal tissues and discovered they were also made of cells. They proposed that all living things are made of cells. All these observations, and some more from other scientists, led to Rudolf Virchow’s
conclusion that all new cells in an organism come from preexisting cells.
Now that we’ve seen some of the important events in the development of cell theory,
let’s bring back our answer choices to choose the correct sequence of these
events. The correct answer choice is (A). Manufacturing and using simple microscopes, determining that plants are comprised of
cells, determining that all living organisms are comprised of cells, understanding
that new cells are produced from preexisting cells.
