1. Cells The Building Blocks of Life

2. How Did the Earth Form? We do not know for certain how the Earth formed. Most scientists agree that the Earth formed about 4.6 billion years ago. That is 4,600,000,000 years ago.

3. Two Theories of How Life on Earth Formed Stanley Miller’s Theory of LifeStanley Miller’s Theory of Life The Volcanic Theory of LifeThe Volcanic Theory of Life

4. Stanley Miller’s Theory of Life This theory states that a mixture of gases and water was struck by lightning and formed a “tar-like” substance that allowed living things to develop. Also known as “Primordial Soup”

5. The Volcanic Theory of Life The Volcanic Theory of Life states that the cooling planet had lots of volcanoes putting gases into the air. These gases condensed into rain that formed oceans. Single cell organisms evolved into plant life then animal life.

6. How did Cells Form? Several Theories of How Cells Formed: –Cells arose in shallow pools containing “soup” of chemicals. These chemicals become combined and formed cells. –Cells formed in beds of clay that allowed substances (chemicals) to be contained and produce living things – cells. –Meteors and asteroids carried water, containing life (cells) to the Earth.

7. Which Cell Theory Is True? We still do not know for sure how cells formed.

8. Spontaneous Generation? The Theory of Spontaneous Generation states that life could arise from non-living matter.The Theory of Spontaneous Generation states that life could arise from non-living matter. –This theory was disproved in 1668 by Francesco Redi who used raw meat for his experiments.

9. Francesco Redi

10. Redi’s Experiment

11. Producers and Consumers A producer is any organism that makes it’s own food. –Example: green plants A consumer is any organism that can not produce it’s own food. –Consumers are dependent on other organisms to survive. –Example: Man

12. How Do Producers Make Food? PhotosynthesisPhotosynthesis: the process by which green plants convert sunlight into food. –As a waste product, oxygen is released. –At some point in history, early cells evolved and became able to perform photosynthesis. This is important because this allowed an oxygen atmosphere to form and eventually allows for animal life to evolve.

15. Characteristics of Living Things All living things share characteristics, they: –Are made of cells –Are able to move –Perform complex chemical activities –Are able to grow and develop –Are able to respond to their environment –Are able to reproduce

16. What are the Needs of Living Things? In order to survive all living things need: –Energy –Food –Water –Oxygen –Living space –To maintain a proper temperature

17. What is a Cell? The cell is the basic building block of all living things.The cell is the basic building block of all living things. –The first cells on Earth are thought to have evolved ~3.5 billion years ago. –These cells could not produce their own food.

18. All living things are made of cells Plant CellsAnimal Cells

20. Cell Theory The current cell theory states that: –All living things are made of cells. –Cells are the basic unit of structure and function in living things. –Living cells only come from other living cells.

21. What Are Cells Made Of? Organelles, or “tiny organs”, are the structures that make up a cell.Organelles, or “tiny organs”, are the structures that make up a cell. Organelles were discovered by Robert Hooke in 1665 while looking at cork cells.Organelles were discovered by Robert Hooke in 1665 while looking at cork cells.

22. How Do Cells Function? Each of the organelles in a cell has a defined function. There are many organelles that make up a cell. –These include the cell wall, cell membrane, nucleus, cytoplasm, endoplasmic reticulum, ribosomes, lysosomes, mitochondria, vacuoles, chloroplasts. All organelles working together create the cells structure.

24. Cell Organelles – Cell Wall cell wallsupport protectionThe cell wall provides support and protection for the cell. cell wallThe cell wall is rigid. Cell wallsCell walls are only found in plant cells.

25. Cell Wall – only in plants

26. Cell Organelles – Cell Membrane The cell membrane is the “doorway” of the cell. Cell membranes control the movement of materials into and out of the cell. –Pores are the openings in the cell membrane. Cell membranes provide support and protection. –In plant cells the cell membrane is found just inside the cell wall. –In animal cells the cell membrane is the outermost organelle.

28. Cell Membrane

29. Cell Organelles - Nucleus The nucleus is the “control center”, or “brain” of the cell which controls all activities in the cell.The nucleus is the “control center”, or “brain” of the cell which controls all activities in the cell. The nucleus has three parts:The nucleus has three parts: –Nuclear membrane –Chromosomes –Nucleolus

30. Cell Organelles - Nucleus nuclear membraneThe nuclear membrane controls the movement of materials into and out of the nucleus. chromosomesThe chromosomes direct the activities within the cell and also pass on genetic traits to the next generation. nucleolusThe nucleolus, or “little nucleus” is the site of ribosome production.

31. Cell Organelles - Cytoplasm Cytoplasm is the clear, thick jelly- like substance that contains all the organelles.Cytoplasm is the clear, thick jelly- like substance that contains all the organelles.

32. Cell Organelles – Endoplasmic Reticulum The endoplasmic reticulum, or ER, is the tubular transportation system throughout the cell.The endoplasmic reticulum, or ER, is the tubular transportation system throughout the cell.

33. Endoplasmic Reticulum Smooth and Rough

34. Cell Organelles - Ribosomes Ribosomesprotein factoriesRibosomes are the protein factories of the cell. ribosomesMost ribosomes are found attached to the outside of the endoplasmic reticulum. –This location helps the cell with efficiency of production and transport.

35. Ribosomes

36. Cell Organelles - Lysosomes Lysosomes“clean up crew”Lysosomes are the “clean up crew” of the cell. LysosomesLysosomes are involved in the digestive process of the cell. –Enzymes break down large food into smaller bits for the mitochondria to use. –Lysosomes –Lysosomes are not common in plant cells.

38. Cell Organelles - Mitochondria MitochondriapowerhouseMitochondria are the “powerhouse” of the cell and supply most of the energy for the cell.

39. Cell Organelles - Vacuoles VacuolesVacuoles are the “storage tanks” of the cell. VacuolesVacuoles can store food, water, or waste. vacuoles –In plant cells vacuoles are common. Usually one large vacuole per cell. vacuoles –In animal cells vacuoles are not common. Usually several small vacuoles per cell.

41. Cell Organelles - Chloroplasts Chloroplasts“energy producers”Chloroplasts are the “energy producers” of plant cells. Chloroplastsonly found in plant cellsChloroplasts are only found in plant cells. ChloroplastschlorophyllChloroplasts contain green chlorophyll that captures energy from the sun.

42. How Do Materials Move Into and Out Of The Cell? Materials enter and leave a cell by one of three methods: –Diffusion –Osmosis –Active Transport

43. What is Diffusion? DiffusionDiffusion is the process by which molecules of a substance move from areas of high concentration to areas of low concentration. selectively permeable. –The cell membrane is selectively permeable.

45. Diffusion from high concentration to low concentration

46. What is Osmosis? OsmosisOsmosis is the diffusion of water into or out of a cell. do not require energyBoth diffusion and osmosis do not require the cell to use up it’s energy.

47. What is Active Transport? Active transport carriesActive transport is the process by which the cell “carries” a substance in or out. This requires the cell to use its energy. When does active transport occur? –If the cell membrane is not permeable for the substance. –If the concentration levels inside and outside the cell are not different enough.

48. How Do Cells Grow? Cells do not grow in size. Why Not? Instead cells grow by increasing their numbers. –T–This process is called c cc cell division.

49. Cell Division Cell division in a series of stages or phases. The most important concept is that: –A–A–A–A parent cell divides into two daughter cells.

50. Two Types of Cell Division Mitosis forms identical daughter cells Meiosis forms daughter cells with half the chromosomes of parent cell

51. Cellular Reproduction

52. Egg and Sperm Cells - Fertilization

53. Meiosis - Sexual Reproduction Result is daughter cells with half the chromosomes

54. Mitosis – Asexual Reproduction Result is two identical cells

55. What are the Phases of Cell Division Phase 1: InterphasePhase 1: Interphase Phase 2: ProphasePhase 2: Prophase Phase 3: MetaphasePhase 3: Metaphase Phase 4: AnaphasePhase 4: Anaphase Phase 5: TelophasePhase 5: Telophase Phase 6: CytokinesisPhase 6: Cytokinesis

56. Cell Division – Interphase: Chromosomes are Copied Chromosomes look threadlike – called chromatin.Chromosomes look threadlike – called chromatin. Centrioles appear outside the nucleus.Centrioles appear outside the nucleus. Near the end of phase 1 cell division begins:Near the end of phase 1 cell division begins: –Chromosomes are copied

57. Interphase

58. Cell Division – Prophase: Mitosis Begins Mitosis is the process of cell division where the nucleus divides into two nuclei and two identical daughter cells are formed.Mitosis is the process of cell division where the nucleus divides into two nuclei and two identical daughter cells are formed.

59. Prophase

60. Cell Division – Metaphase: Chromosomes attach to spindle In metapahse the chromosomes attach themselves to the spindle fibers.In metapahse the chromosomes attach themselves to the spindle fibers. The centromere is what attaches the chromosomes to the spindle.The centromere is what attaches the chromosomes to the spindle.

61. Metaphase

62. Cell Division – Anaphase: Chromosomes begin to separate In anaphase the chromosomes begin to separate.In anaphase the chromosomes begin to separate. The centromere splits and each pair of chromatids begin to move toward the ends of the cell.The centromere splits and each pair of chromatids begin to move toward the ends of the cell.

63. Anaphase

64. Cell Division – Telophase Two new nuclei form In telophase two new nuclei formIn telophase two new nuclei form Chromosomes uncoil and are surrounded by a nuclear membrane.Chromosomes uncoil and are surrounded by a nuclear membrane. A nucleolus reappears.A nucleolus reappears. Cell division is complete.Cell division is complete.

66. Cell Division – Cytokinesis Two daughter cells form In Cytokinesis two new daughter cells form.In Cytokinesis two new daughter cells form. Cell membrane “pinches” cell in the middle forming two identical daughter cells.Cell membrane “pinches” cell in the middle forming two identical daughter cells. –In plant cells a cell wall forms around each daughter cell. Process of cell division is now over.Process of cell division is now over.

68. What Is Cell Specialization? In multicellular organisms, cells not only complete its own life activities, but also performs a function that contributes to the life of the organism.In multicellular organisms, cells not only complete its own life activities, but also performs a function that contributes to the life of the organism. Within multicellular organisms there is division of labor or specialization.Within multicellular organisms there is division of labor or specialization. –The work of keeping the organism alive is divided up among different parts of the organism.

69. Levels of Specialization Cells combine to form Tissues combine to form Organs combine to form Organ systems combine to form Organism

70. More Specialization Students combine to form Classes combine to form Grades combine to form Schools combine to form District

71. What are Tissues? TissuesTissues are cells that are similar in structure and function that combine together. –Example: bone cells form bone tissue –Other examples: muscle tissue, nerve tissue, connective tissue.

72. Bone Tissue and Muscle Tissue

73. What are Organs? Organsare groups of different tissues that work together.Organs are groups of different tissues that work together. –Example: the heart is an organ made of muscle tissues and blood tissue –Other organs: brain, stomach, skin

74. Organs – Heart and Stomach

75. What are Organ Systems? Organ systemsOrgan systems are a group of organs working together to perform a specific function for the organism. –Examples: skeletal system, muscular system, digestive system.

76. Organ Systems

77. What are Organisms? OrganismsOrganisms are an entire living thing that carries out all the basic life functions. –Examples: Humans, cat, fish, fly

78. Some Organisms