Lesson 1

1 2 You will also need
a clean flat area to do the projects:
or or
5 Cells, Nuclei & DNA You can build toy villages, space stations, castles complete
with parapets and drawbridges, or pirate ships with cannons
by stacking layer upon layer of individual,
snap together plastic bricks.
CELLS! All living things are made of That includes YOU!!! Cells are the D B U I L I N G ! BLOCKS of LIFE 6 Like models made from plastic bricks,
multi-cellular organisms
are made of many, many cells.
like animals,
are made
of cells.
Magnified model
of skin cells
Your whole body
is made up of layer
upon layer of cells.
Magnified model
of leaf cells
7 Your body is made of billions and billions and billions of cells!

Your cells come in many shapes and sizes.
red blood
neuronal (NEW ron all) cell in your brain muscle cell stomach cells
About 15
red blood cells
can fit end to end
across the width
of a human hair.
How SMALL is
a red blood cell?
9 All cells come from other CELLS! Mother cells grow and divide
into daughter cells,
over and over again.
10 The mother cell
makes a copy
of materials
inside her!
Let's say
that AGAIN!
One mother cell
grows and
into two
daughter cells.
A daughter cell
grows to become
a MOTHER cell.
The MOTHER cell
divides into two daughter cells.
Click on each cell
to look inside it.
1 2 3
11 Start with a wad of clay
and shape it into an egg.

It can also be oblong
or rectangular or
any simple shape you choose.

Cells come in many
shapes and sizes!
To model Find either: Cell Division 1
your clay CELL
by adding clay.

Make it twice
its original size.
Pinch your CELL inward
at its center.
Divide it completely
into TWO
If a mother cell can divide
every 20 minutes,
how many cells
will there be in:
in 20 minutes Mother cells
grow and divide
into daughter cells,
over and over again.
in 60 minutes
or 1 hour
1 2 in 40 minutes 3 4 in 120 minutes
or 2 hour
The first cell has only doubled one time: 2 cells. The first cell has doubled twice: 2 x 2 = 4 cells. The first cell has doubled 3 times: 2 x 2 x 2 = 8 Now the first cell has doubled SIX times: 2 x 2 x 2 x 2 x 2 x 2 = 64 cells.
14 After 2 hours, there are 64 cells from just one cell.
That is still a fairly modest number of cells.
BUT NOT FOR LONG! Remember: Every 20 minutes all the cells double.
One hour is 60 minutes, so there are 3 doublings in an hour.

Now suppose the cells continue to multiply for seven hours?
How many doublings would that be?
That would be 7 hours x 3 doublings/hour = 21 doublings.
If you multiply the number 2 times itself 21 times,
the number you get is above 2 million cells!
15 Very quickly the number of cells can increase to incredibly large numbers.

If a cell divides every 20 minutes,
one single cell can divide into 4,722,366,482,869,645,213,696 cells
in just 24 hours.

One cell into 4.722 billion, trillion!
Not millions.
Not billions.
Almost 5 billion, trillions.
In just 1 days!
16 EXPONENTIAL GROWTH! For billions of years, most life on Earth consisted of these ever dividing single-celled critters, or more precisely,
single-celled organisms - -

These individual cells are so small,
they are invisible to you.
But they are all around you -- in water, in soil,
on your hands, in your mouth and inside your intestines.
The most abundant life forms on Earth even today
are single-celled organisms.
18 SOMETIMES, a daughter cell is not EXACTLY the same as
the mother cell. Change happens. Sometimes the change is helpful.

That helpful change may be passed on
as the daughter cell grows into a mother cell and splits.
With more and more cell divisions,
beneficial changes begin to accumulate.

As time goes on, descendants become more diverse and varied. Some may develop characteristics that enable them to adapt and survive changes in the environment.
19 A lineage refers to
a group of organisms
that descend from
a common ancestor.
common ancestor After eons, something new began
to happen to some of the cells on Earth.

A few of the cell lineages
were made of many cells.

They were multicellular organisms.
Cell Lineages
20 Multicellular Organisms Eventually multicellular organisms were composed of enough cells
to be visible. These ancient
multicellular organisms looked
like worms, fronds, disks and bags.
They appeared in the fossil record during the Ediacaran Period. Some of these soft bodied organisms eventually evolved into the plants and animals you see today.
21 YOU are NOT
a single-celled
The average adult human
has about
30,000,000,000,000 cells.
That's 30 trillion!
22 YOU began as a single cell!

That one cell has divided
into the billions and billions of cells
that is you!

All life on Earth
begins as a single cell!

Let's explore CELLS!
From a single cell to trillions!
23 Remember last universal common ancestor
to ALL cells
All living things appear to die.
But actually, they don’t!
There are special lineages of cells
that do not die.

They are nearly immortal.
They just divide and evolve.

They have a 4.0 billion year old lineage!
has this ancient ancestry.
All cells come from other cells. LUCA
24 The Cell 25