3.1.1 The History of Cytology

Question 1

cell theory

Answer 1

• The use of newly invented microscopes enabled the formation of the cell theory.
• The major tenets of the cell theory are that:
  • The cell is the smallest structural unit of living organisms.
  • Cells arise from preexisting cells.

Question 2

note

Answer 2

• In the 1600s, Anton Van Leeuwenhoek used
  lenses to view “wee beasties,” creatures that couldn’t be seen with the naked eye, such as the Paramecium species pictured on the left.
• From the early to mid 1800s, scientists began to formalize observations about cells. In 1805, Oken proclaimed that all organic beings originate from and consist of vesicles of cells.
• In 1809, Jean Baptiste Lamarck stated the same proposal

Question 3

Robert Hooke

Answer 3

• Later in the 1600s, Robert Hooke, inspired by an approaching meeting with The Royal Society, designed a simple microscope. Using his microscope, Hooke observed that the cork was made of box-like structures that he called “cells.”

Question 4

Matthias Schleiden and Theodor Schwann

Answer 4

• In 1838 and 1839, Matthias Schleiden and Theodor Schwann unified the cell Theory, extending it to include the plant and animal kingdoms.

Question 5

Rudolph Virchow

Answer 5

• In 1858, Rudolph Virchow proposed that cells come from preexisting cells, thus challenging the ongoing theory of spontaneous generation.

Question 6

Louis Pasteur

Answer 6

• performed a series of experiments that disproved spontaneous generation. The illustrations on the left show Pasteur’s experimental design:
• Boiled broth, devoid of microorganisms, is placed in regular and swan-necked flasks.
• In time, bacteria grow in the regular flask. As the broth cools in the swan-necked flask, a pool of condensed water forms in the bottom of the S, sealing the flask. No microorganisms grow in the broth.
• Later, the neck is broken off, and outside air can enter the flask, carrying microorganisms with it. Subsequently the broth becomes contaminated with microorganisms.
• The experiment demonstrates that the microorganisms are airborne and do not spontaneously arise in the broth.

Question 7

In the 1600s, ________________ used glass lenses of his own creation to be the first person to view the cells of microorganisms in rainwater.

Answer 7

• Anton van Leeuwenhoek

Question 8

___________ stated that all living things originate from cells. __________ observed that cork was made of box-like structures called cells. __________ used lenses that he designed to view microorganisms in pond water

Answer 8

• Jean Baptist Lamarck; Robert Hooke; Anton Van Leeuwenhoek

Question 9

True or false?

All living things consist of cells.

Answer 9

• true

Question 10

Which theory states that all organisms are composed of cells?

Answer 10

• the cell theory

Question 11

In the 1800s, which of the following people experimentally demonstrated that living cells cannot arise spontaneously, leading him to conclude that cells only arise from preexisting cells?

Answer 11

• Louis Pasteur

Question 12

Louis Pasteur performed a series of experiments that disproved spontaneous generation. What aspect of his design represented the experimental part of the test?

Answer 12

• Two different kinds of flasks were used – regular and swan-necked