1. Chapter 3: Cell Structure Section 3: Cell Organelles 1 Chapter 3 Cell Structure Cell Organelles

2. Chapter 3: Cell Structure Section 3: Cell Organelles 2 Objectives Describe the role of the nucleus in cell activities. Analyze the role of internal membranes in cell functions. Summarize the importance of mitochondria in eukaryotic cells. Identify three structures in plant cells that are absent from animal cells.

3. Chapter 3: Cell Structure Section 3: Cell Organelles 3 The Nucleus

4. Chapter 3: Cell Structure Section 3: Cell Organelles The Nucleus The Nucleus is the control center of the cell. 4

5. Chapter 3: Cell Structure Section 3: Cell Organelles 5 The Nucleus Surrounded by nuclear envelope –Double membrane consisting of two lipid bilayers –Separates nucleus from the cytoplasm

6. Chapter 3: Cell Structure Section 3: Cell Organelles 6 The Nucleus

7. Chapter 3: Cell Structure Section 3: Cell Organelles 7 The Nucleus Nuclear pores are scattered over surface –Small channels that allow products of nucleus to move into the cytoplasm

8. Chapter 3: Cell Structure Section 3: Cell Organelles 8 The Nucleus

9. Chapter 3: Cell Structure Section 3: Cell Organelles 9 The Nucleus The nucleolus is a region within the nucleus where ribosomes are partially assembled.

10. Chapter 3: Cell Structure Section 3: Cell Organelles 10 The Nucleus The nucleus houses the hereditary information of eukaryotic cells. –Most of the cell’s DNA is stored in the nucleus. –Eukaryotic DNA is tightly wound around proteins.

11. Chapter 3: Cell Structure Section 3: Cell Organelles 11 The Nucleus –DNA usually exists as elongated and thin strands. In this form it is referred to as chromatin.

12. Chapter 3: Cell Structure Section 3: Cell Organelles 12 The Nucleus –Prior to cell division the DNA strands wind up into dense, rod- shaped bodies called chromosomes

13. Chapter 3: Cell Structure Section 3: Cell Organelles 13 Ribosomes

14. Chapter 3: Cell Structure Section 3: Cell Organelles 14 Ribosomes Sites of protein synthesis Made of protein and RNA Two types: –Free –Fixed

15. Chapter 3: Cell Structure Section 3: Cell Organelles 15 Ribosomes “Free” ribosomes –are suspended in cytosol –Make proteins that remain inside the cell

16. Chapter 3: Cell Structure Section 3: Cell Organelles 16 Ribosomes “Fixed” ribosomes –are embedded in the membranes of the endoplasmic reticulum –Make proteins that are to be exported from the cell

17. Chapter 3: Cell Structure Section 3: Cell Organelles 17 Mitochondria

18. Chapter 3: Cell Structure Section 3: Cell Organelles 18 Mitochondria Harvest energy from organic compounds to make ATP

19. Chapter 3: Cell Structure Section 3: Cell Organelles 19 Mitochondria Cells with high energy needs have many mitochondria.

20. Chapter 3: Cell Structure Section 3: Cell Organelles 20 Mitochondria Have two membranes –Outer membrane smooth –Inner membrane greatly folded to increase its surface area

21. Chapter 3: Cell Structure Section 3: Cell Organelles 21 Mitochondria [movie] Mitochondria have their own DNA.

22. Chapter 3: Cell Structure Section 3: Cell Organelles 22 Structures of Plant Cells

23. Chapter 3: Cell Structure Section 3: Cell Organelles 23 Structures of Plant Cells The organelles described so far are found in both plant and animal cells. In addition to those, plant cells have three additional structures: –Cell wall –Chloroplast –Central vacuole

24. Chapter 3: Cell Structure Section 3: Cell Organelles 24 Structures of Plant Cells Cell Wall –Surrounds the cell membrane –Composed of proteins and carbohydrates, primarily cellulose

25. Chapter 3: Cell Structure Section 3: Cell Organelles 25 Structures of Plant Cells Cell Wall –Functions: Provides support Maintains cell shape Provides protection Connects cells to adjacent cells

26. Chapter 3: Cell Structure Section 3: Cell Organelles 26 Structures of Plant Cells Chloroplast –Use light energy to make carbo- hydrates (site of photosynthesis)

27. Chapter 3: Cell Structure Section 3: Cell Organelles 27 Structures of Plant Cells Chloroplast –Found in plants, algae and some unicellular protists

28. Chapter 3: Cell Structure Section 3: Cell Organelles 28 Structures of Plant Cells Chloroplast –Like mitochondria they are surrounded by two membrane and have their own DNA.

29. Chapter 3: Cell Structure Section 3: Cell Organelles 29 Structures of Plant Cells The Chloroplast

30. Chapter 3: Cell Structure Section 3: Cell Organelles 30 Structures of Plant Cells Central Vacuole –Fills much of the interior of plant cells –Stores water, ions, nutrients, and wastes –When full, it makes the cell rigid.

31. Chapter 3: Cell Structure Section 3: Cell Organelles 31 Structures of Plant Cells

32. Chapter 3: Cell Structure Section 3: Cell Organelles 32 Guided Practice Describe the role of the nucleus in cell activities. –The nucleus contains DNA, directs cell activities, and assembles ribosomal proteins and RNA. Describe the role of mitochondria in the metabolism of eukaryotic cells. –Mitochondria produce most of the ATP used in eukaryotic cells.

33. Chapter 3: Cell Structure Section 3: Cell Organelles 33 Cell Structure Cell Specialization

34. Chapter 3: Cell Structure Section 3: Cell Organelles 34 Cell Specialization

35. Chapter 3: Cell Structure Section 3: Cell Organelles 35 Cell Specialization CELL SPECIALIZATION occurs because many forms of life have many levels of organization.

36. Chapter 3: Cell Structure Section 3: Cell Organelles 36 Cell Specialization In most plants, animals, and fungi, cells are organized into different types of tissues. –TISSUES are groups of cells that carry out a common function.

37. Chapter 3: Cell Structure Section 3: Cell Organelles 37 Cell Specialization Different tissues working together make up ORGANS.

38. Chapter 3: Cell Structure Section 3: Cell Organelles 38 Cell Specialization Groups of organs that work together for a common purpose form ORGAN SYSTEMS.

39. Chapter 3: Cell Structure Section 3: Cell Organelles 39 Cell Specialization Levels of Organization Cells  tissues  organs  organ systems  organism

40. Chapter 3: Cell Structure Section 3: Cell Organelles 40 Levels of Organization

41. Chapter 3: Cell Structure Section 3: Cell Organelles 41 Cell Specialization In the human body there are about 200 different types of cells.

42. Chapter 3: Cell Structure Section 3: Cell Organelles 42 Cell Specialization The structure of each of these cells is related to their function.

43. Chapter 3: Cell Structure Section 3: Cell Organelles 43 Cell Specialization The following frames illustrate some of these specializations.

44. Chapter 3: Cell Structure Section 3: Cell Organelles 44 Cell Specialization RED BLOOD CELLS, for instance, have disk-like flattened membranes.

45. Chapter 3: Cell Structure Section 3: Cell Organelles 45 Cell Specialization This shape gives them a maximum amount of surface area while still remaining smooth enough to slide through the smallest capillaries.

46. Chapter 3: Cell Structure Section 3: Cell Organelles 46 Cell Specialization Because red blood cells are manufactured for limited-time use, they have lost nearly all of their internal organelles

47. Chapter 3: Cell Structure Section 3: Cell Organelles 47 Cell Specialization

48. Chapter 3: Cell Structure Section 3: Cell Organelles 48 Cell Specialization Red Blood Cells

49. Chapter 3: Cell Structure Section 3: Cell Organelles 49 Cell Specialization NERVE CELLS are responsible for the rapid conduction of messages throughout the body. –They are very long and have branches that enable them to connect to other nerve cells

50. Chapter 3: Cell Structure Section 3: Cell Organelles 50 Cell Specialization Motor Neuron

51. Chapter 3: Cell Structure Section 3: Cell Organelles 51 Cell Specialization Nerve Cell

52. Chapter 3: Cell Structure Section 3: Cell Organelles 52 Cell Specialization MUSCLE CELLS are able to produce movement.

53. Chapter 3: Cell Structure Section 3: Cell Organelles 53 Cell Specialization Skeletal muscle cells are very long and thin. They are packed with special protein fibers that are able to contract and make the cell shorter.

54. Chapter 3: Cell Structure Section 3: Cell Organelles 54 Cell Specialization Muscle contraction requires a lot of energy so they have many mitochondria.

55. Chapter 3: Cell Structure Section 3: Cell Organelles 55 Cell Specialization

56. Chapter 3: Cell Structure Section 3: Cell Organelles 56 Cell Specialization SkeletalMuscle

57. Chapter 3: Cell Structure Section 3: Cell Organelles 57 There are many other specializations observed in cells. The important thing to remember is: THE STRUCTURE OF CELLS IS RELATED TO THEIR FUNCTION. Cell Specialization