Cells R Us

Background Knowledge

Even Hot Girls Can Enter Running Races

What does that tell you?

All living things…

Seeing is Believing!

Before…

• People just used their eyes (observations)

• “If I don’t see it, it doesn’t exist!”

How do we know that cells exist?

But then, someone invented the microscope!

Anton van Leeuwenhoek built one of the first microscopes in the 1600s.

Robert Hooke named them…

• Cut a piece of oak tree bark called “cork”

• Used a microscope

• “They look like little rooms!”

• “Or like a prison cell!”

Prison Cell vs. Cork Cell

So… then many scientists started using the microscope to look at things

And their observations made it clear that cells were the basic units of life.

In 1838, German botanist Matthias Schleiden studied plants…

“Ah ha! Plants are made of cells!”

In 1839, German biologist Theodor Schwann studied animals…

“Ah ha! Animals are made of cells!”

In 1855, Dr. Rudolf Virchow tried to be Frankenstein… but he failed.

“We can’t create our own new cells!”

“We can only get new cells from already existing cells in our body!”

Collaboration is when scientists work together

The Cell Theory• All living things are made of one or more cells.• Cells are the basic units in living things.• New cells are produced from existing cells.