1. Red Blood Cells
Cancer Cells
CELL UNIT
Learning Goal 1: Describe the cell theory and how it relates to the nature of Science.
White Blood Cells

2. 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”

3. Characteristics of Living Things
Living things are made up of cells.
Living things reproduce.
Living things are based on a universal genetic code.
Living things grow and develop.
Living things obtain and use materials and energy.
Living things respond to their environment.
Living things maintain a stable internal environment.
Taken as a group, living things change over time.

4. Nature of Science
The goal of science is to investigate and understand the natural world, to explain events in the natural world, and to use those explanations to make useful predictions.

5. Discovery of the cell 1665 He called his discovery “cells”.
Robert Hooke looked at a thin slice of cork under a microscope .
He saw thousands of tiny, empty chambers.
Robert Hooke
1665
He called his discovery “cells”.

6. Discovery of the cell 1674 Anton van Leeuwenhoek
I will call them animalcules!
Observed tiny living organisms in drops of pond water.
Anton van
Leeuwenhoek

7. Discovery of the cell Reported the discovery of the nucleus. 1833
Robert Brown
Reported the discovery of the nucleus.

8. Discovery of the cell
Elodea Cells
1839
Onion Cells
Leaf Cells
Concluded that all plants are made up of cells.
Matthias Schleiden

9. Discovery of the cell 1839 Neurons
Concluded with Schleiden that all animals are made of cells.
Heart Muscle Cells
Theodor Schwann
Neurons

10. Schleiden and Schwann’s Cell Theory
The cell is the unit of structure, physiology, and organization in living things.
The cell retains a dual existence as a distinct entity and a building block in the construction of organisms.
Cells form by free-cell formation, similar to the formation of crystals (spontaneous generation).
The third idea of their cell theory was incorrect!!!

11. "Omnis cellula e cellula"
"Omnis cellula e cellula"...  "All cells only arise from pre-existing cells".
Discovery of the cell
Proposes that all cells come from existing cells.
1855
Rudolph Virchow

12. The modern tenets of the Cell Theory include:
1. All known living things are made up of cells.

13. The modern tenets of the Cell Theory include:
2. The cell is structural & functional unit of all living things.

14. The modern tenets of the Cell Theory include:
3. All cells come from pre-existing cells by division. (Spontaneous Generation does not occur).

15. Figure 1-8 Redi’s Experiment on Spontaneous Generation
Section 1-2
OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.
HYPOTHESIS: Flies produce maggots.
PROCEDURE
Uncovered jars
Covered jars
Controlled Variables:
jars, type of meat,
location, temperature,
time
Several
days pass
Manipulated Variables:
gauze covering that
keeps flies away from
meat
Responding Variable:
whether maggots
appear
Maggots appear
No maggots appear
CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

16. Figure 1-10 Spallanzani’s Experiment
Section 1-2
Gravy is boiled.
Flask is
open.
Gravy is teeming
with microorganisms.
Flask is
sealed.
Gravy is free of
microorganisms.
Gravy is boiled.

17. Figure 1-11 Pasteur’s Experiment
Section 1-2
Broth is boiled.
Broth is free of
microorganisms
for a year.
Curved neck
is removed.
Broth is
teeming with microorganisms.

18. The modern tenets of the Cell Theory include:
4. Cells contains hereditary information which is passed from cell to cell during cell division.

19. The modern tenets of the Cell Theory include:
5. All cells are basically the same in chemical composition.

20. The modern tenets of the Cell Theory include:
6. All energy flow (metabolism & biochemistry) of life occurs within cells.