This document provides an overview of cell theory and key concepts in cell biology: 1. It outlines the three main points of cell theory: all living things are made of cells, cells are the basic unit of life, and new cells are produced from existing cells. 2. Important discoveries in cell history are summarized, from Hooke discovering cells in cork to Virchow establishing that all organisms are made of cells. 3. The key structures and functions of prokaryotic and eukaryotic cells are highlighted at a high level.

1. IB Topic 2 Cells

2. Cell Theory A. There are 3 main points 1. All living organisms are composed of cells. 2. Cells are the smallest unit of life. 3. All cells come from pre-existing cells

3. Cell theory: history and evidence A. The discovery of cells is linked to technological advancements (microscopes) B. 1590-Jansen developed the compound microscope (it had two lenses) C. 1665-Robert Hooke discovered the cell 1. Looking at cork 2. Thought the cells looked like chambers 3. Called them ‘cells’, as in jail cells

4. D. 1675-Leeuwenhoek discovered unicellular organisms E. 1838-Mathius Schleiden discovered all plants are made of cells F. 1839-Theodore Schwann discovered all animals are made of cells

5. G. 1855-Rudolph Virchow discovers all organisms are made of cells **organism=any living thing

6. Characteristics of Life 1. Order (organization) – from small to large -Ex: Organelles make up cells. Cell make up tissues. Tissues make up organs. Organs make individuals. 2. Metabolism- organisms take in and release energy 3. Response (to the environment)- response to stimuli

7. 4. Growth and development-heritable programs of DNA direct growth and development (change in one’s shape during life) Examples:

8. 5. Homeostasis-organisms have regulatory mechanisms to maintain their internal environments Examples: body temperature blood sugar osmoregulation 6. Reproduction-the ability to reproduce ones own kind -This follows the theory of biogenesis (life only comes from life)

9. 7. Evolutionary adaptation-life evolves as a result of interaction between organisms and their environment ***Any organism (single cell or multi-cell) that is considered alive must exhibit all of these characteristics.

10. Multicellular organisms A. Multicellular organisms show emergent properties B. Emergent properties arise from interaction of the components *The whole is greater than the parts (Ex: a heart cannot function without the whole body) *A single cell can do nothing on its own, but when you put all of the cells together they can perform many functions

11. Multicellular organisms and differentiation A. Multicellular organisms differentiate to carry out specialized functions B. All cells originated from the same place and all carry the genetic information to perform any function (your toe cell could have been a brain cell)

12. C. In each cell there is only a small amount of activated genetic material Ex: All cells have the genes for taste. The only cells with activated ‘taste’ genes are on your tongue. D. Cell differentiation is determined by a cells position relative to the others and chemical gradients E. Stem cells retain the capacity to divide and have the ability to differentiate along different pathways

13. Stem Cells Have ability to reproduce and differentiate Embryo cells all start out as stem cells Valuable for scientific research May be able to differentiate stem cells to desired cell type These may replace damaged cells

14. Example of stem cell differentiation

15. Homework-Outline one therapeutic use of stem cells for humans or some other animal. DO NOT USE WIKIPEDIA AS YOUR RESOURCE!! You may use any government or university website. Their websites generally end in .edu or .gov.

16. Viewing Cells 1. Light microscopes allow us to: -see color images -have a larger field of view -prepare samples easily -observe living and non-living material **We cannot see most cell organelles 2. Electron microscopes allow us to: -see more detail because they have a higher resolution

17. Comparing microscopes Light microscopes Electron microscopes Focus beams Lenses electromagnets Resolving power 200 nm 0.2 nm Color No staining required/can see color Requires metal dyes/black and white only Object Alive or dead Dead only Expense High school range/cheap Universities/high cost

18. Microscope Vocabulary 1. Resolution-describes clarity of pictures -higher resolution = more detailed pictures -human unaided resolution= 0.1mm (anything further apart than 0.1 mm is viewed as two objects) 2. Magnification-makes objects larger 3. An increase in magnification may reduce the resolution

19. Calculating Linear Magnification A. The formula- Magnification = size of image size of specimen B. Example-the object is magnified by two This is the magnified image. This is the original object. Diameter of the image=4cm Diameter of the specimen=2 cm Find the magnification.

20. C. Scale bars - lines added to micrographs of drawing to help show the actual size of structures Ex. **You must know how to convert between SI Units to perform a magnification problem correctly!! Ex: 1mm = 1 x 10 -3 m 1 mm

21. Common SI Unit Conversions 1nm (nanometer) = 1 x 10 -9 m 1 ų m (micrometer) = 1 x 10 -6 m 1mm (millimeter) = 1 x 10 -3 m 1cm (centimeter) = 1 x 10 -2 m 1m (meter) = 1m 1km (kilometer) = 1 x 10 3 m

22. Calculating linear magnification Calculating linear magnification 1. Use a ruler to find the length of the scale bar. 2. Measure the length of the picture using the same unit that you used to measure the scale bar. 3. Divide the length of the picture by the length of the scale bar and multiply by the number in the scale bar.

23. 4. If you did this correctly you should have only one unit left (it should be the unit that was in the scale bar). This is the size of the object in the picture. 6. Once you have the size of the object you can calculate magnification. 7. Divide the measured size of the picture by the actual size of the object and multiply by the scale bar (with units). 8. When you do this be sure your units are the same. When you divide they should cancel out. 9. If you did this correctly, your magnification should not have a unit.

24. Example: Go to p. 169 Figure 10.1-C. Calculate the magnification. 1. Length of scale bar = 0.8 cm 2. Length of picture = 5.7cm 3. 5.7 cm x 10.0 μ m = 71.25 μ m = actual 0.8 cm size of object (photo) Number given in scale bar of picture

25. 4. To calculate the magnification you must convert the actual size of the object and the measured size of the photo to the same units (meters are usually the easiest). 5. How it looks: a. 5.7 cm= 5.7 x 10 -2 m or 0.057 m (IMAGE SIZE) b. 71.25ųm = 71.25 x 10 -6 m or 0.00007125 m (ACTUAL SIZE) *In (a) the decimal was moved to the left two times (x 10 -2 ) and in (b) the decimal was moved to the left six times (x 10 -6 )

26. 6. Magnification = 0.057 m =800 0.00007125 m 7. The picture is magnified 800 times. Assignment Calculate the magnification for the following images. 1. p. 169 Figures 10.1 d and e 2. p. 860 Figure 43.19 3. p. 921 Figure 46.10 4. p. 114 Figures 7.3 a and b

27. Limitations to Cell Size A. Cells cannot grow indefinitely B. They reach a maximum size and divide. C. Bigger cells are less efficient. -They have to transport materials further. -The smaller the surface area to volume ratio the harder it is for the cell.

28. D. As surface area increases so does the volume. E. Volume increases more rapidly than surface area. F. The rate at which cells can move things in or out depends on the surface area. G. The rate at which things are used or produced depends on the volume.

29. H. Example: SA = 24 in 2 V = 8 in 3 2” 2” 4” 4” SA = l x w x #of sides V = l x w x h SA = 96 in 2 V = 64 in 3 **Volume increases faster than the surface area. In this example the SA increased by 4 and the volume increased by 8.

30. How Big Is A Cell? OBJECT SIZE Eukaryotic 10-100 μ m Prokaryotic 1-5 μ m Nucleus 10-20 μ m Chloroplast 2-10 μ m Mitochondrion 0.5-5 μ m Large virus (HIV) 100 nm Ribosome 25 nm Cell membrane 7.5 nm DNA dbl. helix 2 nm H atom 0.1 nm

31. Prokaryotic Cells E. coli

32. Diagram of a typical prokaryote

33. Prokaryote organelles 1. Cell wall-gives the cell structure and strength 2. Plasma membrane-separates the internal features from the outside environment 3. Cytoplasm-holds cell’s organelles and enzymes 4. Pili-help the cell hold on to other structures and aid in movement

34. 5. Flagella-aid in organism movement 6. Ribosomes-make protein from mRNA 7. Nucleoid-area containing naked DNA 8. Slime capsule-a protective barrier around the cell (may help shield it from antibiotics) More prokaryote organelles

35. An electron micrographs of E. coli ** For IB you must be able to identify the structures on a micrograph. http:// www.cellsalive.com/index.htm

36. Another diagram of a prokaryote

37. Prokaryote reproduction 1. Most prokaryotes divide by binary fission 2. Some reproduce by budding or filamentous growth http://www.bact.wisc.edu/Microtextbook/index.php?module=Book&func=displayarticle&art_id=112

38. Eukaryote Cells Animal cell

39. General Eukaryote Information 1. All eukaryotes have enclosed nuclei and other membrane bound organelles 2. Eukaryotes are true cells (‘eu’ = true) 3. Eukaryotic cells are present in protists, plants, fungi and animal

40. Homework 1. Draw, label and annotate a diagram of a eukaryotic animal cell Include: free ribosomes rough ER lysosomes Golgi apparatus mitochondria nucleus cytoplasm centrioles cell membrane nucleolus DNA (chromatin) smooth ER

41. 1. Animal cells have a secretory vesicle -It secretes glycoproteins that makeup the extracellular matrix -The extracellular matrix functions in support, adhesion and movement The Secretory Vesicle

42. Diagram of a plant cell

43. Plant Cells 1. Organelles found in plants only: -cell wall -chloroplasts-organelle required for photosynthesis -vacuole-membrane bound sac used for storage of organic compounds

44. 2. More on the cell wall -Found in all plants and some prokaryotes -provides rigid support for the cells -made mostly of cellulose -plays important role in turgor (hardening of cells by the intake of water) -prevents cells from taking in too much water Plant Cells

45. Homework: Outline the roles of extracellular components in plants (cell wall) and animals (extracellular matrix).

46. Summary of differences between eukaryotes and prokaryotes! Prokaryotic Cells Eukaryotic cells small cells (< 5 mm) larger cells (> 10 mm) always unicellular often multicellular no nucleus or any membrane-bound organelles always have nucleus and other membrane-bound organelles DNA is circular, without proteins (naked) DNA is linear and associated with proteins to form chromatin (not naked) ribosomes are small (70S) ribosomes are large (80S) no cytoskeleton always has a cytoskeleton cell division is by binary fission cell division is by mitosis or meiosis reproduction is always asexual reproduction is asexual or sexual

47. Cell Membranes A. The Fluid Mosaic Model-model of the plasma membrane B. Designed by Singer and Nicolson

48. C. The model is a mosaic of proteins embedded in a phospholipid bilayer D. The phospholipid bilayer has two layers of amphipathic lipids Hydrophilic heads Hydrophobic tails

49. E. Amphipathic- has a polar head and a non-polar tail F. Hydrophilic=water loving (polar) -found on inner and outer edges of cell membrane G. Hydrophobic=water fearing (non-polar) -found inside the cell membrane Hydrophilic heads Cytoplasm Hydrophobic tails Diagram of cell membrane

51. H. Lipids can move laterally through the cell membrane I. Cholesterol molecules found between the phospholipids may reduce fluidity, but prevent crystallization J. Membranes must be fluid to work

52. K. Proteins make up the mosaic part of the membrane (3 main types) L. Integral proteins -embedded in the membrane (partially or completely M. Peripheral proteins -found in hydrophilic areas only N. Glycoproteins -proteins within the membrane that have carbohydrates attached to them

53. O. Protein functions -antibody recognition -hormone binding sites -electron carriers -channels for passive transport -pumps for active transport

54. Types of Cellular Transport A. Types of passive transport include diffusion, osmosis and facilitated diffusion B. Diffusion-passive movement of particles from and area of high concentration to an area of low concentration -Particles move down the concentration gradients (high to low)

55. C. Illustration of diffusion

56. D. Osmosis-passive movement of water from an area of low solute concentration to an area of high solute concentration E. Hypertonic solution-high solute/low solvent F. Hypotonic solutions-low solute/high solvent G. Isotonic solution-equal solute/solvent http://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/Osmosis.htm Look at the red blood cells, not the black circles.

57. H. Facilitated diffusion -involves transport of charged molecules -does not require energy -charged molecules must diffuse through special proteins (the cannot diffuse through the cell membrane on their own)

58. GET YOUR BOOK.

59. I. Active Transport - requires energy -used when diffusion cannot occur -substances move up the concentration gradient (move from low to high concentrations

60. J. The Sodium Potassium Pump -An example of active transport -Pumps ions against the gradient -Translocates three sodium ions out of the cell for every two potassium ions pumped in -ATP powers the changes in protein structure to transport the ions

61. -ATP phosphorylation=a phosphate group from the ATP is added to the protein -When ATP is broken energy is released -ATP ADP (adenosine triphosphate adenosine diphosphate) J. The Sodium Potassium Pump (continued) Sodium Potassium Pump Sodium Potassium Pump 2

62. K. Other forms of cellular transport Endocytosis-when a cell extends its membrane around a substance in order to engulf it 2. There are two types: -Phagocytosis-when the cell engulfs a solid (‘cell eating’) -Pinocytosis-when the cell engulfs a fluid (‘cell drinking’)

63. 3. Exocytosis-the excretion of macromolecules by vesicles fusing to the plasma membrane 4. Homework: Find an animation of each of the following: -pinocytosis -phagocytosis -exocytosis Send the website URLs to me in an e-mail K. Other forms of cellular transport

64. L. Membrane fluidity The cell membrane is highly fluid allowing it to creating vesicles for endocytosis and exocytosis In endocytosis the membrane becomes slightly smaller In exocytosis the membrane becomes slightly larger Animation for endocytosis and exocytosis

65. ASSIGNMENT Due Tuesday Compare osmosis and diffusion. Compare facilitated diffusion and active transport. Compare endocytosis and exocytosis. Due Wednesday At home, watch the animations that are in the notes. (Click on the hyperlinks and watch the videos.) Make a list of the ones that helped you the most.

66. M. Functions of the Golgi apparatus and rER in exocytosis 1. Golgi apparatus -Prepares substances for exocytosis -Wraps the substances with portions of its own membrane -Creates a vesicle that will join with the cell membrane to release the materials

67. 2. rough ER- -Functions in protein transport -Assists in creating vesicles to move proteins around the cell or out of the cell via exocytosis -The vesicles created by the rER often fuse with the Golgi appartus -Eventually, new vesicles may be formed and transported out of the cell M. Functions of the Golgi apparatus and rER in exocytosis (continued)

68. Cell division A. The cell cycle consist of the following parts: 1. Interphase (3 stages) -G1 -S -G2 2. Mitosis (4 stages) -Prophase -Metaphase -Anaphase -Telophase 3. Cytokinesis (not truly separate from mitosis)

69. B. Interphase 1. G1-Characterized by cell growth and appearance of cell organelles S-Synthesis of DNA (DNA replication) G2-Preparation for mitosis 2. DNA is found in the form of chromatin (unraveled) 3. Interphase is an active period 4. Often makes up about 90% of the cell cycle

70. C. Mitosis 1. Purpose of mitosis is to increase the number of cells without changing the genetic material 2. The daughter cells are identical to the parent cells 3. Mitosis can occur in haploid, diploid or polyploid cells

71. 4. The stages a. Prophase- -chromosomes coil and become visible -mitotic spindles begin forming -centrioles move to opposite poles -nucleolus disappears -nuclear membrane disappears -sister chromatids are joined together C. Mitosis (continued)

72. 4. The stages b. Metaphase- -Chromosomes move to metaphase plate -centromeres attach to spindle fibers C. Mitosis (continued)

73. 4. The stages c. Anaphase- -sister chromatids separate and move to opposite poles -chromatids are now considered chromosomes C. Mitosis (continued)

74. 4. The stages d. Telophase- -chromosomes arrive at poles -spindles disappear -chromosomes become chromatin -nucleus, nucleolus and nuclear membrane reappear C. Mitosis (continued)

75. D. Cytokinesis 1. Division of the cell (specifically, the cytoplasm) 2. It is hard to distinguish cytokinesis from telophase

76. What is the longest stage of the cell cycle? List all steps of the cell cycle in order. In what stage of the cell cycle does DNA replication occur? True or false? All new cells are the same as the old ones. Picture Picture In interphase the DNA is uncoiled. Is the uncoiled DNA chromatin or chromosomes? In what stage of interphase do cell grow and develop organelles?

77. What happens in interphase? What happens in mitosis? What is the first stage of the cell cycle? What is the second stage of the cell cycle? What is the longest stage of the cell cycle? List the steps of interphase (in order). List the steps of mitosis (in order). Draw and label all stages of mitosis. Explain what happens in each step

78. Comparing cell division in plants and animals A. Plant cells do not cleave like animal cells. B. Plant cells do form a cell plate where the metaphase plate was. C. Both cell types will enter interphase after cytokinesis D. Cell division hyperlink Plant Animal

79. Procedures involving mitosis A. Growth (when you get bigger) B. Embryonic development (after the gametes fuse, the cell divides) C. Tissue repair (when you get a cut or abrasion) D. Asexual reproduction (bacteria make copies of themselves)

80. Daughter cells are genetically identical In mitosis all daughter cells are identical to the parent cell. They are genetic duplicates and have the same DNA. DNA is always replicated in S phase of interphase. There is no recombination or crossing over of genetic material.

81. Cancer A. Cancers (tumors) are the result of uncontrolled cell division B. They can occur in any organ or tissue C. Causes: - carcinogens : chemicals that increase the probability of a proto-oncogene mutation (proto-oncogenes control how often a cell divides)

82. C. Causes (continued): - Viruses : may cause cancer by injecting their genetic material into the host’s chromosomes Example: HPV (human papillomavirus) is linked to cervical cancer - Age : changes required for a cell to become cancerous could take a long time to develop -cancer is common in older people -the longer we live the more chances there are for mutations to occur

83. C. Causes (continued): - Diet: diets high in animal fat have been linked to cancer - Environment: sun, asbestos, radiation - Genetics: family history

84. D. Types of tumors 1. Benign: non-cancerous tissue caused by excessive cell division -typically not harmful, unless it becomes significantly large -weight and size can put pressure on blood vessels, nerves or organs 2. Malignant: cancerous mass of tissue -cells divide quickly and without order -can spread to other parts of the body

85. E. Cancer treatments 1. Surgery: remove all cancerous tissue before it spreads -best chance for treatment -only used when cancer is confined to one area of the body (breast cancer/testicular cancer)

86. E. Cancer treatments (continued) 2. Radiation: use energy to kill cancer cells and shrink tumors -ionized energy is released in a beam and directed to specific points -the beam will damage the genetic material of cancerous cells, making it impossible for them to reproduce -side effects: tiredness, skin reactions

87. E. Cancer treatments (continued) 3. Chemotherapy: treatment of cancer with drugs (chemicals) -work by preventing cancer cells from multiplying -side effects: damage to normal cell Ex: Hair and sperm producing cells can be damaged (temporarily)

88. Cancer video

89. # 18. How cells prevent cancer A. Tumor suppressor gene -inhibits cell division -repairs DNA mistakes -tell cells when to die (apoptosis) -about 30 tumor-suppressor genes have been identified -if they are inactivated cancerous cells may develop

90. B. Proto-oncogenes -control how often a cell divides C. Oncogene- mutated forms of genes -cause cells to grow out of control (leads to cancer) # 18. How cells prevent cancer

91. Get an orange book Complete the following assignment. p. 40 #1-2 and 4-6

92. Miscellaneous Be sure your have an understanding of the differences between the following terms: -haploid -centromere -diploid -centrioles -centrosome -chromatin -chromosome -chromatid