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 membrane 2. Bigger and more complex than prokaryotes 3. Have membrane bound Organelles ( golgi, ER, lysosomes…etc) 4. DNA – double-stranded and forms chromosomes (highly organized) 5. Can be uni- OR multicellular organisms 6. Ex: animals, plants, fungi

Prokaryotes 1. NO nucleus 2. NO membrane bound organelles (just ribosomes) 3. ALL are unicellular 4. Smaller than eukaryotic cells 5. Existed before eukaryotic cells (smaller and more simple) 6. DNA – single strand and circular 7. 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 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, O 2, & 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.”

Anton van Leeuwenhoek  Discoveries: : He looked at pond scum under the microscope and discovered small organisms he called animalcules or little animals (Protists) : discovered bacteria hap09/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”

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. ession1/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 /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

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.

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  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?