1. How Cells Are Put Together Chapter 3

2. Cell Theory Every organism is composed of one or more cells Cell is smallest unit with properties of life Continuity of life arises from growth and division of single cells

3. Smallest unit of life Is highly organized for metabolism Senses and responds to environment Has potential to reproduce Cell

4. Structure of Cells All start out life with: –Plasma membrane –Region where DNA is stored –Cytoplasm Two types: –Prokaryotic –Eukaryotic

5. Overview of cells

6. Common eukaryotic organelles

7. Fig. 3-4, p.41 Most Cells Are Really Small

8. Surface-to-Volume Ratio Bigger cell, less surface area per unit volume Above a certain size, material cannot move in or out of cell fast enough

9. 0.51.01.5 0.79 0.06 3.147.07 0.521.77 diameter (cm): surface area (cm 2 ): volume (cm 3 ): surface- to-volume ratio:13.17:16.04:1 3.99:1 Fig. 3-5, p.41

10. Create detailed images of something that is too small to see Light microscopes –Simple or compound Electron microscopes –Transmission EM or Scanning EM Microscopes

11. Limitations of Light Microscopy Cells must be thin enough for light to pass through Structures are usually stained Light microscopes can see details 200 nm in size

12. Electron Microscopy Uses beams of electrons rather than light Electrons are focused by magnets rather than glass lenses Can resolve structures down to 0.5 nm

13. Fig. 3-2a, p.40 Microscopes

14. Structure of Cell Membranes Fluid mosaic model Mixed composition: –Phospholipid bilayer –Glycolipids –Sterols –Proteins

15. Fig. 3-6b, p.42 one layer of lipids Phospholipids

16. Lipid bilayer organization

17. Membrane Proteins Adhesion proteins Communication proteins Receptor proteins Recognition proteins Passive transporters Active transporters

18. Cell membranes

19. Archaebacteria and eubacteria DNA is not enclosed in nucleus Generally the smallest, simplest cells Prokaryotic Cells

20. Typical prokaryotic cell

21. Eukaryotic Cells Have a nucleus and other organelles Eukaryotic organisms –Plants –Animals –Protistans –Fungi

22. Eukaryotic Cell Features Plasma membrane Nucleus Endoplasmic reticulum Golgi body Vesicles Mitochondria Ribosomes Cytoskeleton

23. Table. 3-1, p.45

24. Keeps the DNA molecules separated from metabolic machinery of cytoplasm Makes it easier to organize DNA and to copy it The Nucleus

25. Components: Nuclear envelopeNucleoplasm ChromatinNucleolus The Nucleus

26. Fig. 3-9a, p.46 DNA in nucleus rough ER smooth ER Golgi body chromatinnucleolus nuclear envelope (two lipid bilayers) cytoplasm pore the cell nucleus RNA messages The Nucleus

27. Related organelles where lipids are assembled and new polypeptide chains modified Sorts and ships products to various destinations Consists of endoplasmic reticulum, Golgi bodies, vesicles Endomembrane System

28. The endomembrane system

29. Endoplasmic Reticulum Starts at nuclear membrane and extends throughout cytoplasm Rough ER: ribosome covered, processes proteins Smooth ER: no ribosomes, builds lipids

30. Fig. 3-9d, p.46 smooth ER channel, cross-section smooth ER Endoplasmic Reticulum

31. Golgi Body Puts finishing touches on proteins and lipids that arrive from ER Packages finished material for shipment to final destinations Material arrives and leaves in vesicles

32. Fig. 3-9e-f, p.46 budding vesicle Golgi body plasma membrane Secretory pathway ends. Endocytic pathway begins. Golgi Body

33. Vesicles Membranous sacs that move through cytoplasm Lysosomes Peroxisomes

34. ATP-producing powerhouses Membranes form two distinct compartments ATP-making machinery embedded in inner mitochondrial membrane Mitochondria

35. Fig. 3-10, p.48 outer membrane outer compartment inner compartment inner membrane

36. Chloroplasts Convert sunlight energy to ATP through photosynthesis Found in plants and some protistans

37. Fig. 3-11, p.48 two outer membranes thylakoids (inner membrane system folded into flattened disks)

38. Organelle Origins Nucleus and ER –Infolding of membranes formed compartments Mitochondria and chloroplasts –Endosymbiosis

39. Fig. 3-14d, p.50 flagellum mitochondrion nucleus chloroplast

40. Fig. 3-15a, p.51 DNA infolding of plasma membrane Infolding Bacterial Membranes

41. Present in all eukaryotic cells Cell shape and internal organization Allows organelle movement within cells and, in some cases, cell motility Cytoskeleton

42. Microtubules Largest elements Composed of tubulin Involved in shape, motility, cell division tubulin subunit

43. Microfilaments Thinnest elements Composed of actin Take part in movement, formation, and maintenance of cell shape actin subunit

44. Intermediate Filaments Only in animal cells of certain tissues Most stable cytoskeletal elements Helpful in determining tissue types one polypeptide chain

45. Cilia, Flagellum, and Psuedopod

46. Plant Cell Walls

47. Plant Vs Animal

48. Table. 3-2, p.57