Video Transcript
Which of the following best defines
cell theory? (A) It is the scientific theory
that states that all cells are genetically and structurally identical across all
living organisms. (B) It is the scientific theory
that states that all living animals are made up of groups of differently specialized
cells. (C) It is the scientific theory
that states that cells are the basic unit of life and make up all living
organisms. (D) It is the scientific theory
that states that cells will divide, replicate, and mutate throughout their
lifetime.
Cell theory is a universally
accepted idea that was developed over hundreds of years into the 1800s. Several scientists were credited
with the development of the three principles of cell theory. Let’s discuss these principles
further to correctly answer our question.
The first main principle of cell
theory states that all living things are composed of cells. This may seem obvious nowadays, but
at the time scientists had little understanding of microscopic structures. With the development of the light
microscope, scientists were able to observe microscopic structures, like cells, for
the first time. The idea that all living things are
made of cells was developed based on the findings of Matthias Schleiden and Theodor
Schwann.
The second principle of cell theory
states that cells are the basic unit of life. The cell is the smallest life form
known to man. In fact, some microorganisms, such
as bacteria, only consist of a single cell, whereas others are multicellular and can
be made up of millions or even trillions of cells. This was first proposed by Robert
Hooke, who was the first person to use the term “cell.” Antonie van Leeuwenhoek was the
first person to observe living cells under a microscope, which confirmed this
principle.
Finally, the third principle of
cell theory states that new cells arise from preexisting cells. Therefore, all cells must result
from the division of their parent cells. This was proposed by Rudolf
Virchow. His findings discredited the idea
that cells could spontaneously come into existence, which is what people previously
believed.
Now that we’ve discussed the three
main principles of cell theory, we can pick the correct answer to our question. The option that best defines cell
theory is given by answer choice (C). It is the scientific theory that
states that cells are the basic unit of life and make up all living organisms.
