Mrs. Verde Third Biology – Cells.
Introduction to Cells and Cell Theory.
Introduction
• Living organisms are made up of
• Living organisms can be made up of
or many
of cells
– life forms consist of only one cell
– life forms are made of many cells
Some Unicellular Life Forms
•
•
•
– a mostly friendly bacteria that
– a pond water creature that
– a pond water predator that may
Some Multicellular Life Forms
•
•
•
– a common
– a common creature that
– a life form that may
Humans & Cells
•
•
•
•
Made of trillions of cells
Of those trillions there are only about
Example:
,
All humans began as
&
that grew & divided into
!
Microorganisms live all over and inside our body!
•
(surface & deep layers)
•
.
•
.
•
.
•
,
&
.
• The
(trillions) are
by
the
,
& other microorganisms by
at least a factor of
!!
(For every 1 human cell, we have 10 microorganisms living with us)
Types of Cells
1. Prokaryotes
 Evolutionarily ancient (
)
 first cells on earth & the only life form for billions of years before more
complex cells came along
 Have
 outer boundary keeping insides in
Mrs. Verde Third Biology – Cells.









.
 genetic material floats around cell
 “pro” = before, “karyon” = nucleus
Most often unicellular organisms
 ie:
2. Eukaryotes
More complex cells –
prokaryotic ancestor
Outer membrane (like prokaryotes)
around genetic material (DNA) =
“Eu” = true, “karyon” = nucleus
Membranes also surround internal sections of the cell =
Involved in
&
within
the cell
Examples:
,
&
Notice the Complexity between Prokaryotes & Eukaryotes
History of Cell Discovery

– English scientist,
discovered cells while looking through one of the first microscopes
 Looked at
and described what he saw as “tiny boxes or honeycombs”
 Named the boxes “
” as they
reminded him of the cells in monasteries
 Thought cells only
.




used a handmade
microscope to observe pond scum & discovered
.
He called them “
”
He also observed blood cells from fish, birds, frogs, dogs, and humans
Therefore, it was known that
as well as
plants
,
Mrs. Verde Third Biology – Cells.
Next 150 - 200 years - Very little research on cells because widely accepted view of life
was maintained by the church, which frowned on modern science
Their theory was based on observations such as…
 Dead logs were the source of mushrooms
 Rotting meat was the source of flies
 Mouldy hay was the source of mice
– living organisms arose from non-living objects
How Would You Disprove Spontaneous Generation?
• Many scientists were sceptical of Spontaneous Generation & set about to
understand how organisms come into existence (through the scientific method!)
A jar of rotting meat


. - .
Observed the nucleus in the epidermis of an orchid

a German professor of botany,
conclusively identified the first plant cells and concluded that

–
was a close friend of Schleiden, stated

–
known as the father of modern pathology
Discovered that all disease results as an
Proved that
living matter
Omnis cellula e cellula



, a German physiologist, who
, German physician, now
not from non-
Modern Microscopes
(SEM)


Bombards the object with a high-energy
Electrons bounce off the
picture
and make a
Mrs. Verde Third Biology – Cells.
Assignment
1. Examples of Cells
8 examples – 4 animal/4 plant with images
2. Write the tenets of the cell theory and theories.
3. Find the Modern Cell theory and then compare with one given in class.
List the differences.