DO NOW 9/8/15


What is a cell and why do we have
cells?
Give one complete sentence.
Cell Theory and
Prokaryote vs.
Eukaryote
What is a Cell?

Cell – Basic unit of living things.
Organisms are either:
 Unicellular – made of one
cell such as bacteria and
amoebas.
OR
 Multicellular – made of
many cells such as plants
and animals.
Microscopes


Light Microscope – magnifies tiny
organisms up to 1,000 times.
-Uses light and lenses.
-We use these.
Electron Microscope – magnifies
up to a million times.
-Uses electrons.
The Discovery of Cells
before
nucleus
true
nucleus
Eukaryotes
1.
2.
3.
4.
5.
6.
Has a nucleus with a nuclear membrane
Bigger and more complex than prokaryotes
Have membrane bound Organelles
(golgi, ER, lysosomes…etc)
DNA – double-stranded and forms
chromosomes (highly organized)
Can be uni- OR multicellular organisms
Ex: animals, plants, fungi
Prokaryotes
1.
2.
3.
4.
5.
6.
7.
NO nucleus
NO membrane bound organelles (just
ribosomes)
ALL are unicellular
Smaller than eukaryotic cells
Existed before eukaryotic cells
(smaller and more simple)
DNA – single strand and circular
Ex: ALL Bacteria
WE DO: WHAT AND WHY
Similarities vs
Differences
THEY DO: With your partner next to you,
create a chart with similarities and
differences between prokaryotes and
eukaryotes
Eukaryote VS. Prokaryote Picture
Food For Thought

A scientist recently discovered a new
organism. Upon looking at it under a
microscope, you see an organism that
possess ribosomes, a circular DNA strand
and a cell membrane. You do not see
visible evidence of mitochondria or other
membrane bound organelles. Is this
organism a prokaryote or eukaryote?
Why?
Do Now 9/9
The organism to the left is a
Euglena. It has the ability to
move like an animal cell
because of its flagellum (tail)
and can also undergo
photosynthesis to make its own
food. Would this organism be
considered a prokaryotic or a
eukaryotic organism? Why?
Cell Size
Surface area : Volume
Cell Size Limits
Are whale cells the same size as sea
stars cells?
Yes!
THEY DO: TPS. Discuss this question with 1 partner
Cell Size Limitations

Getting things into cell at an efficient rate




Removing things from the cell quickly


Nutrients
Water
Oxygen
wastes
DNA limits cell size

If cell is too big then DNA cannot make enough
proteins to support the cell
What limits the size of cells?
Surface Area to Volume Ratio - How much space is on the
outside (cell membrane) compared to the space on the inside of the
cell.
As the surface area of something increases, it’s volume increases
faster
Large Cell
It takes more
time for the
nutrients to
reach the
center of this
cell
Smaller cell
It takes less
time for the
same nutrients
to reach the
center of this
cell
THEY DO


What are some advantages of
having smaller cells
Discuss with your partner: 3
minutes
Conclusion



As cell size increases, the surface area
to volume ratio Decreases (small
surface area to volume ratio), which
can lead to death of a cell.
Having a large surface area to
volume ratio is important to the
functioning of cells since it gets
materials, nutrients, O2, & wastes into
& out of it faster.
Cells divide before they get too big!
Food For Thought
King Kong, a famous movie monster, was a
large over sized gorilla with a bit of an anger
problem.
1.Could an animal this size exist?
2.If this animal existed, would it possess few
large cells or millions of small cells?
Cell Theory and
the Scientists
Who Helped
Shape It
Scientists and
the Cell Theory
Anton van Leeuwenhoek



http://en.wikipedia.org/wiki/Anton_van_Leeuwenhoek
Born: October 24,
1632
Died: August 30,
1723
He is known as the
“Father of
Microscopy.”
Anton van Leeuwenhoek

Discoveries:
- 1673: He looked
at pond scum
under the
microscope and
discovered small
organisms he
called animalcules
or little animals
(Protists)
- 1676:
discovered
bacteria
http://www.kent.k12.wa.us/staff/TimLynch/sci_class/c
hap09/lesson_protista/Protista_Lesson.html#Algae
Robert Hooke




http://www-groups.dcs.st-and.ac.uk/~history/PictDisplay/Hooke.html
Born: July 18, 1635
Died: March 3, 1703
Wrote and published
“Micrographia”
Known as the “English
Father of Microscopy”
Robert Hooke
Contributions:
- He observed pieces of
cork from the bark of a
cork tree under the
microscope.
- His observations led
him to coin the word
“cell.”
- “Cell”- means little
rooms in Latin
- He compared the
small boxes to the
small rooms that monks
lived in.
http://www.learner.org/channel/courses/essential/life/s
ession1/closer1.html
Matthias Schleiden

Born: April 5, 1804
Died: June 23, 1881

German botanist


http://www.britannica.com/eb/article9066147/Mathias-Jacob-Schleiden

Discovered that all
plants were made of
cells
Contributed to the
creation of the cell
theory
Theodor Schwann

Born: December 7,
1810
Died: January 11, 1882

German zoologist


http://www.nndb.com/people/357/000096069/

Concluded that all
animals are made of
cells.
Contributed to the
creation of the cell
theory
Rudolph Virchow

Born: October 13, 1821
Died: September 5, 1902

German pathologist



http://en.wikipedia.org/wiki/Image:Rudolf_Virchow.jpg
He is known as the
“Father of Pathology.”
Discovered that all living
cells come only from other
living cells.
The Cell Theory
1.
2.
3.
All living things are made of cells.
Cells are the basic units of
structure and function in living
things.
Living cells come only from other
living cells.
Food For Thought


Observation: Every year in the spring, the
Nile River flooded areas of Egypt along
the river, leaving behind nutrient-rich mud
that enabled the people to grow that
year’s crop of food. However, along with
the muddy soil, large numbers of frogs
appeared that weren ’ t around in drier
times
The above statement does not
agree with which of the 3 parts of
the cell theory? Why?