1. How many cells do you think could fit on the head of a pin?
About 1,600 average-sized cells!

2. What is a cell?
The smallest unit of matter that can carry out all the processes of life
Basic unit of all living things!

3. Molecules and Compounds
Building up to cells
Atoms
Molecules and Compounds
Organelles
Cells

4. A little bit of history

5. Robert Hooke (1665) Cork under microscope Called spaces “cells”
Was actually dead outer walls of tree bark cells

6. Anton van Leeuwenhoek (1673)
Made microscopes with better magnification
First person to observe living cells
Spirogyra

7. Cell Theory
The work of Hooke and Leeuwenhoek led to the cell theory- has 3 parts

8. In “normal talk,” what does “theory” mean?
“I have a theory about ____”
To have a hunch
To have an idea

9. In “Science Talk,” theories:
Supported by evidence, not hunches
Can never be proven- only disproven

10. Cell Theory All life forms are made of one or more cells.
Cells only arise from pre-existing cells.
The cell is the basic unit of life.

11. At your table:
For each part of the cell theory, draw a picture to illustrate the statement.
All life forms are made of one or more cells.
Cells only arise from pre-existing cells.
The cell is the basic unit of life.

12. Why are cells so special?
Able to differentiate
Stem cell = general, unspecialized cell
Becomes specialized with time
Examples: skin cells, macrophage cells, neurons

13. Differentiation

14. Why else are cells so special?
Have divisions of labor- they are organized.
Organelles (“little organs”) are in cells
Nucleus, mitochondria, etc.
Have unique jobs
One main goal: to keep cell alive

15. Divisions of Labor Car factory: Cells:
Workers have specific jobs to get things done efficiently
Common goal: to build a car
Cells:
Organelles have specific jobs to get things done efficiently
Common goal: to keep the cell alive

16. Why can’t we have big cells?
Limited by surface area to volume ratio
Cells need to get things in/out through their membranes
If cells were huge, it would be harder to get stuff in/out (bigger distance to cover)
We’ll explore this in more depth shortly…

17. Be ready to answer!
Name
What did Robert Hooke do?

18. Be ready to answer! What was Anton van Leeuwenhoek the first to see?
Name
What was Anton van Leeuwenhoek the first to see?

19. Be ready to answer! Read the statement:
A scientist has one cell in a petri dish. When she (or he) comes back, there are now two cells in the dish. Which part of the cell theory does this represent?
Name

20. Be ready to answer! Read the statement:
Name
Read the statement:
A rock has no cells, therefore it is not alive. Which part of the cell theory does this represent?

21. Be ready to answer!
Name
What is the other part of the cell theory that hasn’t been mentioned yet?

22. Be ready to answer!
Explain “differentiation.”
Name

23. Be ready to answer!
What does it mean when someone says that cells have divisions of labor?
Name