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. Has a nucleus with a nuclear membrane2. Bigger and more complex than prokaryotes3. Have membrane bound Organelles

(golgi, ER, lysosomes…etc)

4. DNA – double-stranded and forms chromosomes (highly organized)

5. Can be uni- OR multicellular organisms6. Ex: animals, plants, fungi

Prokaryotes

1. NO nucleus2. NO membrane bound organelles (just

ribosomes)

3. ALL are unicellular4. Smaller than eukaryotic cells5. Existed before eukaryotic cells

(smaller and more simple)6. DNA – single strand and circular7. 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 SizeSurface area : Volume

Cell Size LimitsAre 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

Nutrients Water Oxygen

Removing things from the cell quickly 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

It takes more time for the nutrients to reach the

center of this cell

Large Cell

It takes less time for the same nutrients to reach the center of this cell

Smaller 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

Born: October 24, 1632

Died: August 30, 1723

He is known as the “Father of Microscopy.”

http://en.wikipedia.org/wiki/Anton_van_Leeuwenhoek

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/chap09/lesson_protista/Protista_Lesson.html#Algae

Robert Hooke

Born: July 18, 1635 Died: March 3, 1703

Wrote and published “Micrographia”

Known as the “English Father of Microscopy”

http://www-groups.dcs.st-and.ac.uk/~history/PictDisplay/Hooke.html

Robert HookeContributions:

- 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/session1/closer1.html

Matthias Schleiden

Born: April 5, 1804 Died: June 23, 1881

German botanist

Discovered that all plants were made of cells

Contributed to the creation of the cell theory

http://www.britannica.com/eb/article-9066147/Mathias-Jacob-Schleiden

Theodor Schwann Born: December 7, 1810 Died: January 11, 1882

German zoologist

Concluded that all animals are made of cells.

Contributed to the creation of the cell theory

http://www.nndb.com/people/357/000096069/

Rudolph Virchow

Born: October 13, 1821 Died: September 5, 1902

German pathologist

He is known as the “Father of Pathology.”

Discovered that all living cells come only from other living cells.http://en.wikipedia.org/wiki/Image:Rudolf_Virchow.jpg

The Cell Theory

1. All living things are made of cells.2. Cells are the basic units of

structure and function in living things.

3. Living cells come only from other living cells.

Food For Thought Food For Thought Observation:Observation: Every year in the spring, Every year in the spring,

the the Nile River floodedNile River flooded areas of Egypt areas of Egypt along the river, leaving behind along the river, leaving behind nutrient-rich mud that enabled the nutrient-rich mud that enabled the people to grow that yearpeople to grow that year’’s crop of s crop of food. However, along with the muddy food. However, along with the muddy soil, soil, large numbers of frogslarge numbers of frogs appeared appeared that werenthat weren’’t around in drier timest around in drier times

The above statement does not The above statement does not agree with which of the 3 parts agree with which of the 3 parts of the cell theory? Why?of the cell theory? Why?