STRUCTURE AND FUNCTION OF THE CELL

1. STRUCTURE AND FUNCTION OF THE CELL

2. I. All Organisms are Made of Cells • A. The cell is the basic unit of structure & function • B. The cell is the smallest unit that can still carry on all life processes • C. Both unicellular (one celled) and multicellular (many celled) organisms are composed of cells

3. D. Before the 17th century, no one knew cells existed • E. Most cells are too small to be seen with the unaided eye

4. Early Scientists • F. In the early 17th century microscopes were invented & cells were seen for the 1st time • G. Anton Von Leeuwenhoek, a Dutchman, made the 1st hand-held microscope & viewed microscopic organisms in water & bacteria from his teeth

6. Robert Hooke • H. In 1665, an English scientist named Robert Hooke made an improved microscope and viewed thin slices of cork viewing plant cell walls • I. Hooke named what he saw "cells"

7. Matthias Schleiden (1830’s) • 1. botanist studying plants • 2. States all plants are made up of cells

8. Theodore Schwann (1830’s) • 1. zoologist studying animals • 2. Stated that all animals are made up of cells

9. J. In the 1830’s, Matthias Schleidein (botanist studying plants) and Theodore Schwann (zoologist studying animals) stated that all plants and animals are made of cells.

10. RudolfVirchow • K In 1855, stated that cells only arise from pre-existing cells • L. Virchow’s idea contradicted the idea of spontaneous generation (idea that nonliving things could give rise to organisms) • M. The combined work of Schleiden, Schwann, & Virchow is known as the Cell Theory

11. 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 & function in organisms • C. Cells come only from the reproduction of existing cells

12. http://ed.ted.com/lessons/the-wacky-history-of-cell-theory#watchhttp://ed.ted.com/lessons/the-wacky-history-of-cell-theory#watch • Why do you think there were so many heated debates around the development of the cell theory?

13. Exceptions to Cell Theory • Viruses- are they alive??? • Where did the first cell originate from??? • Mitochondria and Chloroplasts (have their own DNA)

14. III. Cell Diversity • A. Not all cells are alike B. Cells differ in size, shape, and function • C. The female egg cell is the largest cell in the body & can be seen without a microscope • D Bacterial cells are some of the smallest cells & are only visible with a microscope

15. E. Cells need surface area of their cell membrane large enough to adequately exchange materials with the environment (wastes, gases such as O2 & CO2, and nutrients) • F. Cells are limited in size by the ratio between their outer surface area & their volume • G. Small cells have more surface area for their volume of cytoplasm than large cells

16. H. As cells grow, the amount of surface area becomes too small to allow materials to enter & leave the cell quickly enough • I. Cell size is also limited by the amount of cytoplasmic activity that the cell’s nucleus can control • J. Cells come in a variety of shapes, & the shape helps determine the function of the cell (e.g. Nerve cells are long to transmit messages in the body, while red blood cells are disk shaped to move through blood vessels)

19. http://dsc.discovery.com/videos/assignment-discovery-shorts-the-cell.htmlhttp://dsc.discovery.com/videos/assignment-discovery-shorts-the-cell.html

20. IV. Prokaryotes • A. Prokaryotic cells are less complex • B. Unicellular • C. Do not have a nucleus & no membrane-bound organelles

21. D. Most have a cell wall surrounding the cell membrane & a single, looped chromosome (genetic material) in the cytoplasm • E. Include bacteria & blue-green bacteria • F. Found in the kingdoms Archaebacteria and Eubacteria

23. V. Eukaryotes • A. More complex cells • B. Includes both unicellular & multicellular organisms • C. Do have a true nucleus & membrane-bound organelles • D. Organelles are internal structures in cell’s that perform specific functions

25. F. Entire eukaryotic cell surrounded by a thin cell membrane that controls what enters & leaves the cell G. Nucleus is located in the center of the cell H. The nucleus contains the genetic material (DNA) & controls the eukaryotic cell’s activities

26. I. Eukaryotes include plant cells, animal cells, fungi, algae, & protists J. Prokaryotes or bacteria lack a nucleus

28. Eukaryotes • K. Found in the kingdoms Protista, Fungi, Plantae, & Animalia Have Cell Organelles

29. Animal cell Bacterial cell Cell size comparison most bacteria • 1-10 microns eukaryotic cells • 10-100 microns • micron = micrometer = 1/1,000,000 meter • diameter of human hair = ~20 microns

30. Bill Nye Greatest Discoveries: The Cell and Microorganisms • http://www.youtube.com/watch?v=0Q7kz75G4Ck&feature=autoplay&list=PL00E31FC99102BE91&playnext=1

31. Why study cells? • Cells  Tissues  Organs  Bodies • bodies are made up of cells • cells do all the work of life!

32. The Work of Life • What jobs do cells have to do for an organism to live… • “breathe” • gas exchange: O2 in vs. CO2 out • eat • take in & digest food • make energy • ATP • build molecules • proteins, carbohydrates, fats, nucleic acids • remove wastes • control internal conditions • homeostasis • respond to external environment • build more cells • growth, repair, reproduction & development ATP

33. The Jobs of Cells • Cells have 3 main jobs • make energy • need energy for all activities • need to clean up waste produced while making energy • make proteins • proteins do all the work in a cell, so we need lots of them • make more cells • for growth • to replace damaged or diseased cells ATP Our organellesdo all thesejobs!

34. Organelles • Organelles do the work of cells • each structure has a job to do • keeps the cell alive; keeps you alive They’re likemini-organs! Model Animal Cell

35. Golgi mitochondria chloroplast ER Why organelles? • Specialized structures • specialized functions • cilia or flagella for locomotion • Containers • partition cell into compartments • create different local environments • separate pH, or concentration of materials • distinct & incompatible functions • lysosome & its digestive enzymes • Membranes as sites for chemical reactions • unique combinations of lipids & proteins • embedded enzymes & reaction centers • chloroplasts & mitochondria

36. Cell Organelles

37. Cell Membrane • A. Separates the cytoplasm of the cell from its environment • B. Protects the cell & controls what enters and leaves • C. Cell membranes are selectively permeable only allowing certain materials to enter or leave

38. D. Composed of a lipid bilayer made of phospholipid molecules

39. E. The hydrophilic head of a phospholipid is polar & composed of a glycerol & phosphate group and points to the aqueous cytoplasm and external environment. • F. The two hydrophobic tails are nonpolar point toward each other in the center of the membrane & are composed of two fatty acids

41. G. When phospholipids are placed in water, they line up on the water’s surface with their heads sticking into the water & their tails pointing upward from the surface. • H. The inside of the cell or cytoplasm is an aqueous or watery environment & so is the outside of the cell. Phospholipid "heads" point toward the water.

43. I. Phospholipid "tails" are sandwiched inside the lipid bilayer. • J. The cell membrane is constantly breaking down & being reformed inside living cells. • K. Certain small molecules such as CO2, H2O, & O2 can easily pass through the phospholipids

44. Membrane Proteins • A. A variety of protein molecules are embedded in the cell’s lipid bilayer.

45. B. Some proteins called peripheral proteins are attached to the external & internal surface of the cell membrane C. Integral proteins or transmembrane proteins are embedded & extend across the entire cell membrane. These are exposed to both the inside of the cell & the exterior environment. D. Other integral proteins extend only to the inside or only to the exterior surface.

46. E. Cell membrane proteins help move materials into & out of the cell. F. Some integral proteins called channel proteins have holes or pores through them so certain substances can cross the cell membrane. G. Channel proteins help move ions (charged particles) such as Na+, Ca+, & K+ across the cell membrane

47. H. Transmembrane proteins bind to a substance on one side of the membrane & carry it to the other side. e.g. glucose I. Some embedded, integral proteins have carbohydrate chains attached to them to serve as chemical signals to help cells recognize each other or for hormones or viruses to attach

49. Fluid Mosaic Model A. The phospholipids & proteins in a cell membrane can drift or move side to side making the membrane appear "fluid".

50. B. The proteins embedded in the cell membrane form patterns or mosaics. C. Because the membrane is fluid with a pattern or mosaic of proteins, the modern view of the cell membrane is called the fluid mosaic model.