Regents Biology, Monday 10/21/13

1. Regents Biology, Monday 10/21/13 • Take a handout and QOD form from the front. • Sit in your normal seats • Take out something to write with. • While you are waiting, answer the question of the day: • How do we know cells exist?

2. Unit #3: All About Cells The words you need to write down are in blue

3. Part 1: Some History • Before the 17th century (1600’s), no one knew cells existed • Most cells are too small to be seen with the unaided eye • In the early 17th century microscopes were invented and cells were seen for the first time

4. Part 1: Some History • Anton Von Leeuwenhoek, a Dutchman, made the first hand-held microscope and viewed microscopic organisms in water and bacteria from his teeth. • His microscopes were very powerful for that time.

5. VonLeeuwenhoek’s Microscope: • Leeuwenhoek's microscope consisted simply of: • A) a screw for adjusting the height of the object being examined • B) a metal plate serving as the body • C) a skewer to impale the object and rotate it • D) the lens itself, which was spherical  

6. Part 1: Some History • In 1665, an English scientist named Robert Hooke made an improved microscope and viewed thin slices of cork viewing plant cell walls. • Hooke named what he saw cells.

7. Part 1: Some History • In the 1830’s, Matthias Schleiden (botanist studying plants) & Theodore Schwann (zoologist studying animals) stated that all living things were made of cells • In 1855, Rudolf Virchow stated that cells only arise from pre-existing cells • Virchow’s idea contradicted the idea of spontaneous generation (idea that nonliving things could give rise to organisms). • The combined work of Schleiden, Schwann, & Virchow is known as the Cell Theory

8. Part 1: Some History • Schwann Schleiden Virchow

9. Part II: Principles of the Cell Theory • A. All living things are made of one or more cells • B. Cells are the basic unit of structure and function in living organisms • C. Cells come only from the reproduction of pre-existing cells

10. Important Points to Remember: • The cell is the basic unit of structure and function • The cell is the smallest unit that can still carry on all life processes • There are both unicellular(one celled) and multicellular(many celled) organisms

11. Part III: Cell Diversity • Although all cells are enclosed by a membrane, not all cells are alike. • Cells differ in size, shape, and function • The female egg cell is the largest cell in the human body and it can be seen without a microscope • Bacterial cells are some of the smallest cells and are only visible with a microscope

12. Part III: Cell Diversity E.coli Bacterial Cells

13. Now a quick video song or two: • www.youtube.com

14. Regents Living Environment Tues. 10/22/13 • Take a handout and a calculator from the front • Pick up your flashcards if you haven’t already • Sit down • Today’s topic is: Cell Size (please correct the unit to #3 All About Cells) • While you are waiting, answer the QOD in the margin on your paper: • Are the cells of humans the same size as the cells of Elephants?

15. Are the cells of humans the same size as the cells of Elephants?? • Why are most cells so small?? • Most cells are microscopic in size • Cells exchange materials across their outer membranes • Cells need the surface areaof their cell membrane large enough to adequately exchange materials with the environment. • Cells need to exchange wastes, gases such as CO2 & Oxygen, water, and nutrientswith their environment. • Cells are limited in size by the ratio between their outer surface area and their volume

16. Why are most cells so small?? • Small cells have moresurface area for their volume of cytoplasm than large cells---they have a larger surface area to volume ratio. • As cells grow, the amount of surface area becomes too smallto allow materials to enterandleave the cell quickly enough • Cell size is also limited by the amount of cytoplasmic activity that the cell’s nucleus can control

17. Why are most cells so small??

18. Why are most cells so small?? • Cells in large organisms arespecialized. • They come in a variety of shapes and the shape helps determine the function of the cell • Example:Nerve Cells are long to transmit messages in the body, while blood cells are disk shaped to move through blood vessels

20. Now we will work on page 36 • Work with a partner • Use a calculator • The formulas for surface area and volume are on the board • Use PENCIL in case you make a mistake

21. Regents Living Environment Weds 10/23/13 • Please take the handouts from the front table • Sit down and take out something to write with • While you are waiting quietly be sure to answer the QOD in the margin of your paper: • What is the benefit of having specialization in a cell or in an organism? What levels of organization help with specialization?

22. Part IV: Two Different Classifications of Cells • There are two different types of cells: Prokaryotic and Eukaryotic

23. 1) Prokaryotic Cells: • are less complex(or sophisticated) • are unicellular organisms only • Do not have a nucleus • Do not have membrane-bound organelles • Most have a cell wall surrounding the cell membrane & a single, looped chromosome (genetic material) in the cytoplasm

24. 1) Prokaryotic Cells: • This group includes bacteria & blue-green bacteria called cyanobacteria. • These organisms are found in the kingdom Monera.

25. 2) Eukaryotic Cells: • These are more complex or sophisticatedcells • Can be eitherunicellular OR multicellular organisms • They have atrue nucleus • They have membrane-bound organelles

26. 2) Eukaryotic Cells: • Entire eukaryotic cell surrounded by a thin cell membrane that controls what gets into and out of the cell (just like a prokaryotic cells) • Eukaryotic organisms include Protists, Algae, Fungi, Plants, and Animals

27. A Comparison:

28. Part V: What are Organelles? • Organelles are structures inside a cell that perform specific functions for the cell. • Organelles are surrounded by either a single or double membrane. • They help cells perform tasks more efficiently

29. Some Common Organelles: • a. Nucleus • b.Chloroplast • c. Golgi • d. Mitochondria

30. The Nucleus: • It is located in or around the center of the cell • It is the largest organelle • Itcontains the genetic material (DNA) & controls the cell’s metabolic activities • Both plantcells and animal cells contain a nucleus. • Prokaryotes (bacteria)do not have a nucleus

32. Cytoplasm: • includes everything between the nucleus and plasma membrane • it surrounds the organelles and is composed of cytosol,which is a jellylike material consisting mainly of water andproteins • ALL cells contain cytoplasm

33. Mitochondria: • Found in all types of eukaryoticcells • Is site of cellular respiration, which is turning glucose into ATP(energy) • Have a double membrane and their own DNA • More active cells like muscle cells have more mitochondria • Inner membrane has folds called cristae for increased surface area—more area for more energygenerating reactions!

34. Mitochondria: draw this and label it in the margin of your paper

35. Ribosome: • Found in both prokaryotic and eukaryotic cells • Is the site of protein synthesis • Makes proteins from messages received from the nucleus

36. Regents Living Environment Thurs 10/24/13: • Take a handout from the front • Pick up your flashcards if you haven’t already • Take out something to write with and your notes • Wait quietly

37. Endoplasmic Reticulum: • Found in eukaryotic cells • May be “smooth” ER or “rough” ER • These are canals for transport of materials through the cell • Also are sites of various chemical reactions • Rough Endoplasmic Reticulum has ribosomes attached to it

38. Endoplasmic Reticulum:

39. Golgi Apparatus: • Processes, packs, and stores cell’s products such as hormones, proteins, and enzymes • Lysosomes: • These are enzyme filled sacks where molecules are digested • Can digest “food” molecules or dead or damaged organelles • Not found in plant cells

40. Cilia or Flagella: • Cilia are tiny projections on the surfaceof the cell, and cells usually have many of them • Flagella are longer whip-like structures on the surface of the cell, and cells usually only have one or a few of them • Both are for movingthe cell around or for moving materials over the surface of the cell

41. Cytoskeleton: • Found in all cells • Consists of a network of long protein tubes and strands in the cytoplasm to give cells shapeand helps move organelles • Composed of protein structures called microtubules, intermediate filaments, & microfilaments

42. Regents Living Environment Monday 10/28/13 • Pick up your flashcards • Please take a handout from the front table • Sit down and take out something to write with • Check the assignment board

43. Centrioles: • Not found in plant cells, only in animal cells • Found near the nucleus • Involved in cell division • They assist with spindle formation

44. Organelles only found Plant Cells but NOT Animal Cells: • Cell Wall: • Rigid structure that holds the cell’s shape • Located outside of the cell’s plasma membrane • Reinforced with cellulose for strength

45. Organelles only found Plant Cells but NOT Animal Cells: • Chloroplast: • Site of photosynthesis, which is turning solar energy into sugars such as glucose • Contains chlorophyll which is a green pigment • They have a double membrane and their own DNA

46. Chloroplast:

47. Organelles only found Plant Cells but NOT Animal Cells: • Central Vacuole: • Large “bubble” type of space • The plant cell can store water, plant sap, andinorganic materials like minerals or toxins here • When full it pushes out to keep the cell shape rigid

48. Part VI: Cell Membrane • The cell membrane is also considered an organelle. • It separates the cytoplasm of the cell from its environment • It protects the cell and controls what enters and leaves • Composed of a lipid bilayer made of phospholipidmolecules (a bilayer means it has twolayers) • All cell membranes are selectively permeable, meaning that they only allow certain materials to enter or leave

49. Plasma Membrane to label

50. Stop here • Now you will work on page 38 and 44 in your notes • You should finish these for homework tonight • There are also flashcards due Weds. for the following words: • Cell Wall, Chloroplast, Plasma Membrane, Selectively Permeable