1. 3-1 New Unit: Cells

2. 3-2

3. 3-3

4. 3-4

5. 3-5

6. 3-6

7. 3-7

8. 3-8

9. 3-9

10. 3-10

11. 3-11 Some History… 1665- Robert Hooke looks at a thin slice of cork under a microscope. 1674- Anton van Leeuwenhoek observes small living organisms in pond water 1839-Mathias Schleidan concludes that all plants are made up of cells 1839-Theodor Schwann concludes that all animals are made up of living cells 1855- Rudolph Virchow proposes that all cells come from existing cells

12. 3-12 Cell Theory All living things are composed of cells Cells are the basic units of structures and function in living things New cells are produced from old cells

13. 3-13 Cell Characteristics What characteristics do we use to define a cell? All cells have two things in common 1. The are surrounded by a barrier called a cell membrane 2. At some point in their lives the contain genetic material.

14. 3-14 Prokaryotes vs. Eukaryotes Cells can be split up in two broad categories, depending on whether they contain a nucleus Prokaryotic cells have genetic material that is not contained in the nucleus Eukaryotic cells contain a nucleus in which their genetic material is separated from the rest of the cell.

15. 3-15 Prokaryote

16. 3-16 Eukaryote

17. 3-17 Functions of the Cell Basic unit of life Protection and support Movement Communication Cell metabolism and energy release

18. 3-18 Cell Characteristics Plasma Membrane –Outer cell boundary Cytoplasm –Cytosol –Cytoskeleton Organelles –Specialized structures that perform specific functions

19. 3-19 Cell Membrane ALL cells are surrounded by a thin flexible barrier called the cell membrane Many cells have an additional barrier called the cell wall The cell membrane regulates what goes in and out of the cell The cell membrane is called a lipid bilayer

20. 3-20 Cytoplasm Cellular material outside nucleus but inside plasma membrane Cytosol: Fluid portion Cytoskeleton: Supports the cell –Microtubules –Microfilaments –Intermediate filaments

21. 3-21 Organelles Small specialized structures for particular functions Most have membranes that separates interior of organelles from cytoplasm Related to specific structure and function of the cell

22. 3-22 Nucleus DNA dispersed throughout Consists of : –Nuclear envelope: Separates nucleus from cytoplasm and regulates movement of materials in and out –Chromatin: Condenses to form chromosomes during cell division –Nucleolus: Assembly site of large and small ribosomal units

23. 3-23 Centrioles In specialized zone near nucleus: Each unit consists of microtubules Before cell division, centrioles divide, move to ends of cell and become spindle fibers

24. 3-24 Ribosomes Sites of protein synthesis Composed of a large and small subunit Types –Free –Attached to endoplasmic reticulum

25. 3-25 Endoplasmic Reticulum Types –Rough Attached ribosomes Proteins produced and modified –Smooth Not attached ribosomes Store enzymes, Manufacture lipids

26. 3-26 Golgi Apparatus Modification, packaging, distribution of proteins and lipids for secretion or internal use Flattened membrane sacs stacked on each other

27. 3-27 Function of Golgi Apparatus

28. 3-28 Mitochondria Provide energy for cell Major site of ATP synthesis Membranes –Cristae: Infoldings of inner membrane –Matrix: Substance located in space formed by inner membrane

29. 3-29 Lysosomes -Small organelles filled with enzymes -Involved in digestion or breakdown of lipids carbohydrates, and proteins. -Also involved in breaking down old organelles, and removing “junk” of the cell.

30. 3-30 Chloroplasts Capture energy from sunlight and convert it into chemical energy during photosynthesis Found in plants and other organisms.

31. 3-31 Vacuoles Store materials such as water, salts, proteins, and carbohydrates. Plants use vacuoles as support for heavy structures Contracting vacuoles are found in some animals and single celled organisms to pump out excess water.

32. 3-32 Cilia Appendages projecting from cell surfaces Capable of movement Moves materials over the cell surface

33. 3-33 Flagella Similar to cilia but longer Usually only one exists per cell Move the cell itself in wavelike fashion Example: Sperm cell

34. 3-34 Microvilli Extension of plasma membrane Increase the cell surface Normally many on each cell One tenth to one twentieth size of cilia Do not move

35. 3-35 Organelle DNA Some organelles have their own DNA These include the mitochondria, ribosomes, and chloroplasts What implications do you think this has? Evolutionary?

36. 3-36 Endosymbiosis Proposed by Lynn Margulis in 1970. Suggests that mitochondria and chloroplasts were once free living organisms and were taken into other cells as endosymbiotes.

37. 3-37 Cell Membrane Passive Transport and Active Transport Inheritance

38. 3-38 Lipid Bilayer Two layers of lipids = bilayer

39. 3-39 Lipid Bilayer Hydrophobic = water fearing Hydrophilic = water loving

40. 3-40 Lipid Bilayer Also contains proteins and carbohydrates Proteins = channels and pumps Carbs = identification

41. 3-41 Lipid Bilayer In order to survive, every cell must take in and eliminate substances This means the cell membrane must allow certain substances to penetrate it. It is called selectively permeable

42. 3-42

43. 3-43 Chromosome Structure

44. 3-44 Cellular Aspects of Aging Cellular clock Death genes DNA damage Free radicals Mitochondrial damage