Download The Cell Theory

RECAP
BIOLOGICAL FACTS
Explain the
postulates of the
cell theory
STEM_BIO1
1/12-Ia-c-1
Pre-Activity:
Did You Know?
What is the smallest unit of Life?
Did You Know?
How many cells make up an
average human being?
 The average human being
is composed of around
100 Trillion individual
cells!!!
 It would take as many as
50 cells to cover the area
of a dot on the letter “i”
Did You Know?
 What cell type that can no longer regenerate once used up?
Did You Know?
 What type of cell can carry Oxygen and supplies it through
the body?
Did You Know?
 What is the smallest cell in nature?
Did You Know?
 What is the biggest cell in nature?
The Cell Theory
Youtube video about Cell Theory
Guide Question:
What were the major discoveries
leading to the creation of Cell
Theory?
What is the cell theory about?
Discovery of Cells
 1665- English Scientist, Robert Hooke, discovered cells while
looking at a thin slice of cork.
 He described the cells as tiny boxes or a honeycomb
 He thought that cells only existed in plants and fungi
Anton van Leuwenhoek
 1673- Used a handmade microscope to observe
pond scum & discovered single-celled organisms
 He called them “animalcules”
 He also observed blood cells from fish, birds,
frogs, dogs, and humans
 Therefore, it was known that cells are found in
animals as well as plants
R-noticed that pollen grains in water jiggled around
1827-33 - Robert Brown
called “Brownian motion”
-discovered
Robert Brown the nucleus
Nucleus
Human Cheek Cell
1838 - Matthias Schleiden
A botanist who concluded that all plants are made of cells.
Typical Plant
Cell
1839 - Theodor Schwann
A zoologist who concluded that all animals are made of cells.
Nerve Cells
1855 - Rudolph Virchow
A physician who did
research on cancer cells and
concluded
“Omnis cellula e cellula”.
“All cells are from other
pre-existing cells.”
Based on the discovery of Cell, if you are a scientist how
would you derive the Cell Theory?
The 3 Basic Components of the Cell Theory :
1. All organisms are composed of one or
more cells.
(Schleiden & Schwann)(1838-39)
2. The cell is the basic unit of life in all living
things. (Schleiden & Schwann)(1838-39)
3. All cells are produced by the
division of preexisting cells.
(Virchow)(1858)
The Cell Theory Complete
 The 3 Basic Components of the Cell Theory were now
complete:
 1. All organisms are composed of one or more cells.
(Schleiden & Schwann)(1838-39)
 2. The cell is the basic unit of life in all living things.
(Schleiden & Schwann)(1838-39)
 3. All cells are produced by the division of preexisting cells.
(Virchow)(1858)
How Has The Cell Theory Been Used?
 The basic discovered truths about cells, listed in the Cell
Theory, are the basis for things such as:
 Disease/Health/Medical Research and Cures(AIDS, Cancer, Vaccines,
Cloning, Stem Cell Research, etc.)
STEM CELL RESEARCH
The research started simple question “How can the
various parts of the human body began forming and
how may it be possible to replicate the processes.
Modern Cell Theory
Assignment:
on Modern Cell Theory
 Modern Cell Theory contains 4 statements, in addition to the
original Cell Theory:
1. The cell contains hereditary information(DNA) which is passed on
from cell to cell during cell division.
2. All cells are basically the same in chemical composition and
metabolic activities.
3. All basic chemical & physiological functions are carried out inside
the cells.(movement, digestion,etc)
4. Cell activity depends on the activities of sub-cellular structures
within the cell(organelles, nucleus, plasma membrane)
Historical Background:
1. Robert Hooke
-1665 – coined the term cell
2. Corti
– 1772 – saw substance within the cell
3. Fontana
-1781- used the term nucleolus
4. Robert Brown
– 1831 – saw the nucleus
5. Dujardin
– 1835 – used the term sarcode
6. Mattias Jacob Schleiden & Theodore
Schwann
-1839- cell doctrine
7. Strasburger
– illustrated cell division
8. Hugo Von Mohl
– 1846 – used the term protoplasm
9. Max Schulze
– protoplasm as physical basis of life
10. Thomas Huxley
– protoplasm as chemical basis of life
11. Rudolph Virchow
– 1858 – cell generalization
12. Schimper
–1883- used the term plastid.
13. Frederich Mischer
– 1868- saw DNA in pus
14. Benda Altmann
– coined the term mitochondria
15. Camilo Golgi
–1898- Golgi bodies
16. John Dalton
– 1900 -Neuron in owl
17. Palade
– 1900 – ribosome
18. Porter
– 1900 – Endoplasmic reticulum
19. Daniel Davson
– 1900 – Cell membrane as
sandwich like
20. Christian de Duze
– Lysosome in rat
Application:
Explain the Cell Theory in your own
words
How has the knowledge of Cell
Theory help you understand life.
Some Parting Thoughts
 Humans are just an intricately designed
community of cells, which must work together
to survive
The next time you will
be asked what is the
essence of life?