Cells are Basic to Life The human body is composed of trillions of cells There are about 200 different types of cells Each cell turns raw materials from food you eat and air you breathe into molecules the body needs ID: 1043578
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1. CELLS
2. Introduction to Cells
3. Cells are Basic to Life The human body is composed of trillions of cells.There are about 200 different types of cells. Each cell turns raw materials from food you eat and air you breathe into molecules the body needs.3
4. Cell Diversity Cells have many different shapes & functions. Sperm CellsNerve CellsCheek CellsRed Blood Cell4
5. Microscopes Enable Us to See CellsMicroscopes were first developed and used in the 1600’s.Robert Hooke coined the term “cell” while observing dead cork cells in 1665.5
6. Anton van LeeuwenhoekThe father of microbiologyFirst to use a microscope to study microorganisms such as bacteria and protozoansA replica of Leeuwenhoek’s microscope developed in the 1670’s.6
7. The Cell TheoryAll living things are made of one or more cells.Cells are the basic unit of structure and function in living things.All cells come from pre-existing cells.7
8. Two Major Classes of CellsProkaryotic CellsSmaller, simpler cellsLack a nucleus and most other organellesEx. Bacteria & ArchaeaEukaryotic CellsHave a nucleus surrounded by its own membrane and other membrane-bound organelles.Ex. Protists, Fungi, Plants & Animals8
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10. Plant Cells vs. Animal Cells10
11. Starch Grain11
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13. Question:Compare and contrast prokaryotic cells and eukaryotic cells.13
14. Answer:Both prokaryotic and eukaryotic cells have plasma membranes, ribosomes and genetic material (DNA), but only eukaryotic cells have a nucleus and other membrane-bound organelles.14
15. Question:Name two structures found in plant cells that are not found in animal cells.15
16. Answer:Any two of the following:Cell wallChloroplastLarge Central Vacuole16
17. Membrane Structure & Function
18. Plasma MembraneThe plasma membrane regulates substances moving into and out of a cell. The membrane is composed of phospholipids which have hydrophilic heads & hydrophobic tails. Draw a picture18
19. Phospholipid BilayerThe plasma membrane is a phospholipid bilayer; a fluid-like membrane in which the heads face outward and the tails face inward.The tails, tucked inside, act as a selectively permeable membrane.Because the membrane is fluid-like, proteins drift about freely much like “icebergs” in the ocean.19
20. Notice the different types of proteins (blue) embedded in the plasma membrane. Each type has a specific function.20
21. Selectively Permeable MembraneThe plasma membrane allows some substances to cross more easily than others and blocks the passage of some substances altogether.Three primary ways substances cross the membrane:Passive Transport – no energy requiredActive Transport – requires energyVesicle Transport – for large molecules21
22. Passive Transport22
23. DiffusionDiffusion occurs because molecules are always in motion. Ex. Dropping food coloring into a glass of water. Eventually, the dye will be evenly distributed. 23
24. Diffusion and EquilibriumWhen diffused molecules are equally distributed, and the system is in balance, it has reached equilibrium.Diffusion stops at equilibrium.Molecules are still in motion, but there is no net change in concentration.24
25. Facilitated DiffusionThe transport protein provides a “path” for certain molecules to pass through.25
26. OsmosisThe passive transport of water across a selectively permeable membrane is called osmosis.26
27. Osmotic SolutionsHypertonic – solution with higher concentration of soluteIsotonic – solutions with equal concentration of soluteHypotonic – solution with lower solute concentration 27
28. Osmosis & Plant Cells28The plant cell wall maintains cell shape.
29. Question:What types of membrane transport are shown in this diagram?29
30. Answer:The fat-soluble molecules are crossing the membrane by simple diffusion.The water-soluble molecules are crossing the membrane through a membrane protein, so this is facilitated diffusion.30
31. Question:Describe the solutions in this beaker using the terms hypertonic and hypotonic.semipermeable membrane31
32. Answer:The solution on the left is hypotonic relative to the solution on the right which is hypertonic.32
33. Question:In this solution, only water can cross the membrane. Draw a picture showing how the solutions will change over time.semipermeable membrane33
34. Answer:34
35. Active TransportActive transport occurs when a cell uses energy to move a molecule across the membrane – usually from low concentration to high concentration.35
36. Transport of Large MoleculesIf molecules are too large to cross the membrane, they are packaged in vesicles, which are small sacs that specialize in moving products into, out of, and within a cell.To move products out, the cell uses an active transport process called exocytosis and to take products in, the cell uses endocytosis.36
37. Endocytosis37
38. Exocytosis38
39. Organelles
40. OrganellesEach mini-organ, or organelle, in the cell has a specific job to do. The various organelles are suspended in a gel-like fluid called cytoplasm.40
41. Two Major CompartmentsNucleusSurrounded by nuclear membraneContains DNANucleolus (red) makes ribosomesCytoplasmContains all other organellesCytoplasmNucleus41
42. NucleusThis diagram shows the nucleolus and nuclear envelope with pores.The function of the nucleus is to direct the cell’s activities.42
43. RibosomesThe site of protein synthesisSome are on the surface of rough ERSome are suspended in the cytoplasm43
44. Endoplasmic ReticulumThe endoplasmic reticulum (ER) is a network of membranes that manufactures & transports cell products. Two types: Rough ER has ribosomes on the surface, makes and transports proteinsSmooth ER does not have ribosomes, makes other things like lipids44
45. Endoplasmic Reticulum45
46. Golgi ApparatusProducts from ER travel in vesicles to the Golgi ApparatusModifies, stores and routes proteins to their destinations 46
47. VacuolesMembrane-bound sacs in the cytoplasm that store undigested nutrientsPlants have a large central vacuole that stores waterLarge Central Vacuole47
48. LysosomesLysosomes are membrane-bound sacs that contain digestive enzymes that can break down molecules.Lysosomes have several functions:Digest nutrients and nourish the cellDestroy harmful bacteria Recycle damaged organelles w/o harming the cell48
49. Digestion by LysosomesWhen lysosomes digest nutrients, they fuse with a food vacuoleEnzymes in the lysosome digest the food particles and nutrients are released for the cell to usefood vacuolelysosomeenzymesdigestion occurs49
50. Question:Identify structures 1, 2, 5 & 8.50
51. Answer:1: Nucleolus2: Nucleus 5: Rough ER8: Smooth ER51
52. Path of Cellular ProductsProduced at ribosomes on Rough ERTravel by vesicle to Golgi apparatus where they are modified and refinedTravel by vesicle to plasma membraneProducts released from cell by exocytosis52
53. ChloroplastsChloroplasts are the photosynthetic organelles found in some cells of plants and algae – not found in animal cells.53
54. MitochondriaSite of cellular respiration Provide the main energy source for cells; ATPSometimes called the “powerhouse” of the cell54
55. Question:Identify structures 6, 9 & 14.55
56. Answer:6: Golgi Apparatus9: Mitochondrion14: Plasma Membrane56
57. Cytoskeleton & Cell Movement
58. CytoskeletonA network of fibers extending throughout the cytoplasmAlways changing, with new extensions building at the same time that others are breaking apart58
59. Cytoskeleton FibersMicrotubules are straight, hollow tubes of protein that give shape and rigidity.Microfilaments are thinner, solid rods of protein that enable the cell to move or change shape. Intermediate filaments are rope-like filaments that provide stability to cell structure.59
60. Fibers of the CytoskeletonMicrotubulesIntermediate filamentsMicrofilaments60
61. Flagella Long, thin, whip-like structures that are composed of microtubulesWave with an “s” shaped motion to enable cells to move61
62. CiliaCilia are short microtubules More numerous than flagellaUsed to move fluids over the cellCilia lining the respiratory tract are shown here.62
63. Flagella move cells and cilia move substances past or over cells.63CiliumFlagellum
64. Cell MovementSome cells that are capable of movement:White blood cellsProtozoansSlime moldsWhite blood cell engulfing anthrax bacteria.64
65. Question:Compare and contrast cilia and flagella.65
66. Answer:Both are composed of microtubules and are involved in movement.Cilia are shorter, more numerous, and move substances over the cell surface. Flagella are longer, cells usually only have one or two, and they allow the cell to move. 66
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69. The EndCells