DO NOW 9/8/15 What is a cell and why do we have cells? Give one complete sentence.
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Transcript of DO NOW 9/8/15 What is a cell and why do we have cells? Give one complete sentence.
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.
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
Similarities vs Differences
THEY DO: With your partner next to you, create a chart with similarities and differences between prokaryotes and eukaryotes
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 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
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?
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?