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2. Chapter Menu Lesson 1:The Cell Cycle and Cell Division Lesson 2:Levels of Organization Click on a hyperlink to view the corresponding lesson.

3. 2.1 The Cell Cycle and Cell Division cell cycle interphase centromere mitosis cytokinesis prophase metaphase anaphase telophase daughter cell cell plate homologous chromosome sister chromatid

4. 2.1 The Cell Cycle and Cell Division The Cell Cycle • Life cycle of cells • Includes phases of growth, development, and reproduction

5. 2.1 The Cell Cycle and Cell Division Phases of the Cell Cycle • The phase of the cell cycle when a cell is preparing to reproduce is called interphase. • The phase when a eukaryotic cell reproduces is called mitotic phase.

6. 2.1 The Cell Cycle and Cell Division Phases of the Cell Cycle (cont.)

7. 2.1 The Cell Cycle and Cell Division Length of a Cell Cycle • Length of time for cell cycle is different for different types of organisms and cells • During earliest stages of animal growth, cell cycle can repeat quickly • Dependent on the type of organism and type of cell • Cell cycles repeat quickly in early stages of animal growth

8. 2.1 The Cell Cycle and Cell Division Characteristics of Interphase • Cell performs specific functions during interphase. • Stomach cells might produce substances that aid in digestion. • Plant cells might perform cellular respiration.

9. 2.1 The Cell Cycle and Cell Division Characteristics of Interphase (cont.) • During interphase, the chromosomes in a nucleus are so thin they cannot be observed with a light microscope. • For each chromosome in one set of chromosomes, there is a similar chromosome in the other set of chromosomes. • Each pair of similar chromosomes is called a pair of homologous chromosomes.

10. 2.1 The Cell Cycle and Cell Division Phases of Interphase • There are three phases—G1, S, and G2. • G1: cell grows and carries out its usual cellular functions • Some cells remain in G1 and do not reproduce, such as muscle cells, red blood cells, and some nerve cells.

11. 2.1 The Cell Cycle and Cell Division Phases of Interphase (cont.) • S phase: the chromosomes in a cell’s nucleus continue growth but also replicate • Sister chromatid: copy of chromosome • Centromere: a region near middle of each chromatid that holds together each sister chromatid

12. 2.1 The Cell Cycle and Cell Division Phases of Interphase (cont.) • G2 phase: continues growth and replication but also replicates organelles • Mitochondria and chloroplasts: have own DNA and can duplicate themselves

13. 2.1 The Cell Cycle and Cell Division Mitosis • Process in which the nucleus divides • Cytokinesis: process in which the cytoplasm divides • New cells made by mitosis and cell division replace dead cells Mitosis

14. Replicated DNA condenses into chromosomes. • Nuclear membrane disappears? 2.1 The Cell Cycle and Cell Division Phases of Mitosis • Prophase: first phase of mitosis in which the DNA twists into tight coils and the nucleus membrane breaks apart

15. Chromosomes align at the middle of the cell. 2.1 The Cell Cycle and Cell Division Phases of Mitosis (cont.) • Metaphase: second phase of mitosis in which the replicated chromosomes move to middle of cell and line up end-to-end

16. Centromeres divide. • Sister chromatids separate. 2.1 The Cell Cycle and Cell Division Phases of Mitosis (cont.) • Anaphase: third phase of mitosis in which the sister chromatids separate and the centromeres divide

17. Nuclear membranes form. 2.1 The Cell Cycle and Cell Division Phases of Mitosis (cont.) • Telophase: final phase of mitosis in which a new membrane forms around each set of chromosomes

18. 2.1 The Cell Cycle and Cell Division Dividing the Cell’s Components • During cytokinesis the final stage of cell division, the cytoplasm and its components divide to form two identical daughter cells. • A disc, or cell plate, forms between the two new nuclei that are dividing.

19. 2.1 The Cell Cycle and Cell Division Results of Cell Division • After mitosis and cell division, the original cell—the parent cell—no longer exists. • The chromosomes of daughter cells are identical in number and type to each other and to the parent cell. • All the cells in the body have identical chromosomes except sperm and egg cells.

20. 2.1 The Cell Cycle and Cell Division Lesson 1 Review • A • B • C • D When a cell is preparing to reproduce, what phase of the cell cycle is it in? A S phase B prophase C interphase D mitosis

21. 2.1 The Cell Cycle and Cell Division Lesson 1 Review • A • B • C • D In which phase does the nucleus divide? A G2 B mitosis C cytokinesis D cell division

22. 2.1 The Cell Cycle and Cell Division Lesson 1 Review • A • B • C • D In which type of cell would you expect to see a cell plate form? A plant cell B animal cell C stomach cell D parent cell

23. End of Lesson 1

24. 2.2 Levels of Organization cell differentiation stem cell tissue organ organ system

25. 2.2 Levels of Organization Single-Celled Organisms • Need to be organized • Carry out all the functions needed for their survival, including: • obtaining nutrients • waste removal • movement • protection • reproduction

26. 2.2 Levels of Organization Prokaryotes • Single-celled organisms that do not have nuclei or other organelles, such as bacteria • Still have structures with specific functions • Same processes that occur in eukaryotic organelles happen along specialized membranes in bacteria

27. 2.2 Levels of Organization Eukaryotes • Protists are single-celled eukaryotes • Include amoeba and some fungi • Are more complex than prokaryotes • Have a nucleus and membrane-bound organelles

28. 2.2 Levels of Organization Eukaryotes (cont.) • Single-celled eukaryotes are more complex than cells in multicellular eukaryotes. • Single-celled: exist alone and must do everything needed for their survival within the single cell • Multicellular eukaryotes: rely on one another and cannot survive alone

29. 2.2 Levels of Organization Multicellular Organisms • Multicellular organisms require organization. • They have many cells and usually have more than one type of cell. How do animal and plant cells work?

30. 2.2 Levels of Organization Cell Differentiation • Process in which cells become different types of cells • Differentiated cells: specialized structures and shapes for specific functions, such as liver cells or brain cells • Once most human cells differentiate, they cannot become any other type of cell. Cell Specialization

31. 2.2 Levels of Organization Stem Cells • Cells that can become different types of cells

32. 2.2 Levels of Organization Tissues • Groups of similar cells that work together and perform a function

33. 2.2 Levels of Organization Tissues (cont.)

34. 2.2 Levels of Organization Organs • A group of similar tissues that work together to perform a function

35. 2.2 Levels of Organization Organs (cont.) • Human organs include the heart, lungs, brain, and muscles. • Plant organs have organs, such as leaves, that store nutrients, exchange gases, transport water or nutrients, or perform photosynthesis.

36. 2.2 Levels of Organization Organ Systems • One or more organs that work together and perform one or more functions

37. 2.2 Levels of Organization Human Organ Systems Organ Systems (cont.)

38. 2.2 Levels of Organization Human Organ Systems Organ Systems (cont.)

39. 2.2 Levels of Organization Human Organ Systems Organ Systems (cont.)

40. 2.2 Levels of Organization Organisms • The most complex unit of living things is a multicellular organism. • Multicellular organisms usually have many organ systems. • Each organ system has its own function but is dependent on other organ systems.

41. 2.2 Levels of Organization Organisms (cont.)

42. 2.2 Levels of Organization Lesson 2 Review • A • B • C • D Where do bacteria carry out the processes that occur in the organelles of eukaryotes? A nucleus B chloroplast C smooth ER D specialized membranes

43. 2.2 Levels of Organization Lesson 2 Review • A • B • C • D What are undifferentiated cells called? A stem cells B tissues C prokaryotes D liver cells

44. 2.2 Levels of Organization Lesson 2 Review • A • B • C • D What organ system produces hormones that control body functions? A skeletal B lymphatic C nervous D endocrine

45. End of Lesson 2

46. Chapter Resources Menu Chapter Assessment California Standards Practice Concepts in Motion Image Bank Science Online Interactive Table Virtual Lab BrainPOP Click on a hyperlink to view the corresponding feature.

47. Chapter Assessment 1 • A • B • C • D Each chromosome in one set of chromosomes has a similar chromosome in the other set of chromosomes. What is a pair of similar chromosomes called? A sister chromosomes B homologous chromosomes C daughter chromosomes D parent chromosomes

48. Chapter Assessment 2 • A • B • C • D Sister chromatids are held together at what region of the chromatids? A the ends B the centromere C the cell plate D G1

49. Chapter Assessment 3 • A • B • C • D When do the sister chromatids of each replicated chromosome begin to separate? A prophase B metaphase C anaphase D telophase

50. Chapter Assessment 4 • A • B • C • D By what process do cells become different types of cells with specialized structures and functions? A cell division B mitosis C cell differentiation D the cell cycle