1. Chapter 7: Cell Structure and Function (Section 1)

2. How do we know about cells?
Before the invention of the microscope, people didn’t know that living things were made of cells.
Cells are too small to see with the naked eye
The microscope was invented in the 1600s

3. Important pioneer scientists
Robert Hooke:
In 1665 he used a microscope (advanced technology then!) to look at a piece of cork under the microscope
He saw that the cork was made of many tiny chambers, which he called “cells”
Anton van Leeuwenhoek:
Worked around same time as Hooke
Used a microscope to observe pond
water
Found that there were tiny organisms
living in the water!

5. Important pioneer scientists
Matthias Schleiden (1853): Figured out all plants are made of cells
Theodore Schwann (1854): Figured out all animals are made of cells
Rudolf Virchow (1855): Figured out that new cells could only be made from existing cells

6. Cell Theory All living things are composed of cells
Cells are the basic units of structure and function in living things
New cells are produced from existing cells.

7. New cell technology
New technology has made it easier to see cells and their structures
Electron Microscopes = use beams of electrons to magnify the cell thousands of times (only works on dead cells though )
Transmission electron microscopes (TEM) let us see inside the cell
Scanning electron microscopes (SEM) let us see the outside of the cell
Scanning Probe Microscopes = invented in 1990s, let’s us see DNA and atoms

8. TEM
SEM
Scanning Probe

9. Lots of different cells
Cells come in many shapes and sizes
The two things they all have in common are:
Surrounded by a barrier
called a cell membrane
Contain DNA

10. Prokaryotes vs. Eukaryotes
Smaller
Simpler
No nucleus
Very few internal structures
Examples = bacteria
Larger
More complex
Have a nucleus
Many internal structures
Examples = plant, animal, fungi

11. Prokaryote
Eukaryote

12. Tricks to remember! Pro = No! Eu = True!
No nucleus, which means its DNA is not contained and just floats around inside the cell
Eu = True!
-- Has a true nucleus, which means its DNA is surrounded by a membrane-like structure