1. 4.2 INTRODUCTION TO CELLS

2. CELL DIVERSITY (SHAPE)  Cells come in a variety of shapes  The shape typically reflects the function of the cell  Consider the nerve cell…  Long and thin with many extensions

3. CELL DIVERSITY (SHAPE)  Cells come in a variety of shapes  The shape typically reflects the function of the cell  Consider the skin cell…  Flat, plate like shape

4. CELL DIVERSITY (SIZE)  Cells vary greatly in size  Longest include nerve cells in giant squid and giraffe  Heaviest is thought to be ostrich egg

5. CELL DIVERSITY (SIZE)  Size limited by relationship of cell’s surface area to its volume  Large surface area is good to let large amounts of nutrients in and out

6. CELL DIVERSITY (SIZE)

7. 3 BASIC PARTS OF A CELL 1. Plasma membrane  Cell outer boundary  Barrier between cell and “outside world”  All things entering and leaving the cell must go through plasma membrane

8. 3 BASIC PARTS OF A CELL 2. Cytoplasm  Region inside cell  Includes fluid and cytoskeleton  Includes all organelles except nucleus  Cytosol – “liquid” portion of the cytoplasm where organelles are suspended

9. 3 BASIC PARTS OF A CELL 2. Cytoplasm  Cytosol – “liquid” portion of the cytoplasm where organelles are suspended

10. 3 BASIC PARTS OF A CELL 3. Nucleus  Membrane bound organelle that contains DNA  Controls most functions of a cell

11. 2 BASIC TYPES OF CELLS 1. Prokaryotes  no membrane bound nucleus  No membrane bound organelles  Can have nucleoid region where genetic material is concentrated

12. 2 BASIC TYPES OF CELLS 1. Prokaryotes  Domain Bacteria and domain Archea

13. 2 BASIC TYPES OF CELLS 1. Eukaryotes  Have membrane bound nucleus  Have membrane bound organelles

14. 2 BASIC TYPES OF CELLS 1. Eukaryotes  Domain Eukarya

15. CELLULAR ORGANIZATION  Over time, cells began to form groups  2 types of groups

16. CELLULAR ORGANIZATION 1. Colonies  Group of genetically identical cells  Not truly multicellular  No coordinated cellular activities

17. CELLULAR ORGANIZATION 2. True Multicellularity  Cells have roles  Like cells form tissues  Like tissues form organs  Like organs form organ systems

18. 4.3 EUKARYOTIC CELL ORGANELLES

19. 3 PARTS 1. Plasma Membrane 2. Nucleus 3. Organelles

20. 3 PARTS 1. Plasma Membrane  Selectively permeable – lets only specific molecules in and out of cell  Composed of lipids and proteins  Fluid mosaic model – acts like a fluid  Proteins are like boats floating on water

21. 3 PARTS 1. Plasma Membrane

22. 3 PARTS 1. Plasma Membrane  Peripheral proteins – loosely attached to inside or outside of membrane

23. 3 PARTS 1. Plasma Membrane  integral proteins – permanently attached to cell membrane  Embedded in membrane  May have carbohydrate attached that is a site for viruses and hormones to attach to

24. ORGANELLES 2. Mitochondria  “mighty mitochondria” – powerhouse of cell  Where ATP is made  Have their own DNA  Have outer membrane and inner membrane  Cristae – folds of inner membrane

25. ORGANELLES 2. Mitochondria

26. ORGANELLES Endoplasmic reticulum (ER)  Transports substances around cell  2 types

27. ORGANELLES 3. Smooth ER  Creates and stores lipids and steroids  Breaks down toxins in liver

28. ORGANELLES 4. Rough ER  Studded with ribosomes

29. ORGANELLES 5. Ribosomes  Make proteins  Attach to RNA

30. ORGANELLES 5. Ribosomes

31. ORGANELLES 6. Golgi apparatus  Makes complex molecules out of simple molecules  Processing and packaging

32. ORGANELLES 6. Golgi apparatus

33. ORGANELLES 7. Lysosome  Digests old molecules, waste, foreign substances and old organelles  “cleans up” cell

34. ORGANELLES 8. Centrioles  Help animal cells divide

35. ORGANELLES 9. Cytoskeleton  Gives shape to the cell  Microtubules – hold organelles in place  Spindle fibers used in cell division  Microfilaments – help cell movement and muscle contraction  Made of actin

36. ORGANELLES 9. Cytoskeleton

37. ORGANELLES 10. Cytoplasm  fluid with suspended organelles  Fluid called cytosol

38. NUCLEUS FEATURES 1. Nuclear envelope  Surrounds nucleus  Double layer  Has nuclear pores that provide entry and exit to nucleus

39. NUCLEUS FEATURES 1. Nuclear envelope

40. NUCLEUS FEATURES 2. Nucleolus  Produces the subunits that form ribosomes

41. NUCLEUS FEATURES 3. Chromatin  DNA concentrated here when cell not dividing  Forms chromosomes before cell division

42. 4.4 PLANT CELL ORGANELLES

43. ORGANELLES The following are organelles that are found in plant cells, but are much less pronounced or not found at all in animal cells.

44. ORGANELLES 1. Vacuoles  Storage bubbles  Can store nutrients, waste, nutrients, or water  Can take up 90% of the cell

45. ORGANELLES 2. Plastids  Create and store chemical compounds like lipids and starches  Some have pigments

46. ORGANELLES 3. Chloroplasts  Type of plastid  Produces energy for the cell through photosynthesis  “plant mitochondria”  Contain chlorophyll pigment (green color)

47. ORGANELLES 3. Chloroplasts

48. ORGANELLES 4. Cell wall  Made of cellulose (a starch)  Protection and support  Surrounds the cell membrane