1. Cell Theory Cell theory has three main principles 1.All organisms are composed of one or more cells 2.Cells are the smallest units of life 3.All cells come from preexisting cells

2. Discrepancies: the cell theory( explain)  Striated muscle cells  Algae  fungi

3. Unicellular Organisms  One cell only(move, drift, fixed)  Must carry on life functions.  Nutrition  Metabolism  Growth  Response  Excretion  Homeostasis  Reproduction

4. Limitations on cell size  Metabolism=large number of chemical reactions taking place within a living organism.  The rate of these reactions is proportional to the cell.  The rate and amount of materials absorbed and removed depend on the surface to volume ratio

5.  Small ratio: cell can’t absorb or excrete materials quickly, the cell will also overheat easily because heat produced can’t be eliminated fast enough,

6. Limitations on cell size  Metabolic rate is proportional to cell volume.  Used materials (absorbed)  Waste products(removed)  Small cells overheat, slow entrance of materials and wastes accumulate quickly

7. Multicellular organisms  Organisms consisting of a single mass of cell fused together.  Cooperative groups  No one group is leader, they organize themselves and interact with other groups to have one distinct purpose

8. Emergent properties  These are characteristics of the whole organism  Interaction of component parts of a complex structure

9. Cell differentiation  Different cells=different functions (job or role)  Groups of cells that specialize in the same way to perform the same function = tissue  Tissues= more efficient job  Differentiation: development of cells to carry out specific functions.

10. Gene expression and differentiation  Every cell contains the same set of genes.  Some genes are activated (switched on or being used) = production of a certain cell type.  Differentiation: different sets of genes are expressed and active. This is the key to development

11. Stem cells  Versatile and can differentiate along any pathway to produce any type of cell or tissue  1. divide many times = large quantities of new cells. Used to grow tissues or replace lost or damaged cells.  2. not fully differentiated so they can produce any cell type.

12. Embryonic stem cells  1. regenerate tissues for burn victims  2. type 1 diabetes treatment  3. grow replacement organs  Therapeutic use: therapies or treatments for disease or health issues.  Non therapeutic use:  Production of meat without the cow.

13.  Stem cells: early stages are very versatile.  Later stages they begin to commit to a growth pattern or differentiate.  They will still divide but all will develop in the same way. No longer a stem cell  Stem cells: found in adults  Much repair: bone marrow, skin, liver  Limited repair: brain, kidney, heart

14. Uses of stem cells  Stargardt’s disease (genetic)  Progressive loss of vision until blindness. Use embryonic stem cells to treat.  Leukemia:  Cancer: several specific mutations occur in one cell and that cell divides.  Remove patients stem cells by needle aspiration  Chemotherapy  Return stem cell to patients bone marrow

15. Ethical objections  1. informed consent  2. clear understanding by the patient of the treatment involved  P15 take your own notes in class regarding the sources of stem cells  1. create an embryo( for that purpose only IVF) (abortions)  2. cord blood  3. Adult tissue (e9 Bone marrow)

16. When does life begin  1. sperm fertilizes the egg (IVF)  2. early stage embryo has no human characteristics, can’t feel pain so its ok  3. heartbeat, bone tissue, brain activity. Usually seen a few weeks into development.  4. fetus stage = viable outside the uterus (24 to 28 weeks)  Positive= reduction of the suffering of diseased individuals.

17. Ultrastructure of cells resolution of microscopes  Resolution: making an objects parts distinguishable.  Light microscope limited by the wavelength of light  Electron microscope ; higher resolution the beams of electrons have shorter wavelengths to provide more resolution.  Used for viewing the ultrastructure of cells

18.  Ernst Ruska: 1939 developed the first electron microscope. Used beams of electrons instead of light.

19. Difference between prokaryotes and eukaryotes PROKARYOTESEUKARYOTES  No nucleus  Simple cell structure  Small in size  Found everywhere even in extreme conditions  Have cell walls  Filled with cytoplasm  No organelles  Nucleus: contains chromosomes  Nuclear membrane  Cytoplasm that contains organelles (analogous to organs) specialized functions.  Multicolor  Ingest materials (pinocytosis, phagocytosis)

20. prokaryoteseukaryotes  Do contain ribosomes  Lack membrane bound organelles  DNA called a nucleoid  Plasmid: an extra piece of DNA, circular, contains nonessential genes that may be needed later  Gene for antibody resistance  Contain cilia and flagella  Sexual reproduction (The sperm is the only eukaryotes with flagella)  Compartments within the cell where the organelles are located  Advantage to compartments: concentration of molecules in one area

21. ProkaryotesEukaryotes  Reproduction by binary fission (asexual reproduction) (mitosis)  EXAMPLES bacteria single celled organisms  Diffusion thru the cell wall  No compartments all cytoplasm  Contain ribosomes  Keep material separated  Maintains pH easily  Organelles can move around  See page 21 for a picture and description of each organelle

22. Activity  Draw both a Eukaryotic and Prokaryotic cell.  You will be given a whit piece of paper fold it in half. One half for each cell.  Draw the cell, Label the cell parts, annotate the organelles or parts of each cell.

23. Phospholipid layers  Hydrophilic: water attracting (phosphate) (head)  Hydrophobic: does not attract water (hydrocarbon chain) (tails)  Amphiphatic: has both properties.  Proteins are dark in electron micrographs and phospholipids appear light.

24.  Protein globules were also discovered so the previous model was disproved (Davson- Danielli)  Singer Nicolson : fluid mosaic model

25. Evidence that falsified the Davson Danielle model  P27,28  Freeze etched electron micrographs  Structure of membrane proteins  Fluorescent antibody tagging

26. Membrane proteins  Proteins in the membrane prevent and slow the passage of materials  Active cells with have a higher protein content in the membrane  1. Integral Protein: hydrophobic and found on the hydrocarbon portion of the chain  Transmembrane: extends across the membrane. Hydrophilis part project thru the phosphate head on either side.  Channel protein  Carrier protein

27.  Peripheral protein these are not embedded in the membrane  Hydrophilic  (they are attached to the surface of an integral protein or to the hydrocarbon chain.  Internal cell communication

28.  Lipid bound proteins: found within the bilayer of phospholipids  Glycoproteins: found anywhere and it consists of a sugar and protein together allows for cell communication

29. Cholestrol in membranes  Found only in anmial cell membranes  Lipid = steroid category  Hydrophobic = attracted to the hydrocarbon chain  Contain OH (hydroxyl group) so that portion is hydrophilic and attracted to the phosphate head portion  Found between the phospholipids (p31)

30. FLUIDITYDistance between molecules Temperature increasesincreasesIncreases (molecules are lose Temperature decreases decreasesDecreases (molecules cluster crystalize) Cholesterol/ low tempFluidity increasesIncreases distance between Phospholipids Cholesterol/ high tempFluidity decreasesmolecules are drawn in tighter Saturated fats (single bonds between the carbon atoms) Fluidity decreasesStacked together and closely Unsaturated fats (double bonds between the carbon atoms Fluidity increasesThe molecules don’t stack up together

31.  The amount of cholesterol present varies amongst cells  Keeps the cells in a fluid state (from becoming crystallized)  Reduces permeability ( to other hydrophilic particles)  Allows(helps) the membrane to change shape so vesicles can be formed for transport.

32. Endocytosis  When a small region of the membrane is pulled in and pinched off.  Energy (ATP) is needed for the process  Vesicle formed contains materials from outside the cell (large molecules)  Can contain food (amoeba)  Pathogens (WBC)

33. Vesicle  Allows movement of material and the vesicle itself within the cell membrane  Contents are taken to the area of need.  When you have an increased membrane size then you will see an increased size in the organelle

34. exocytosis  The vesicle fuses with the cell membrane and the contents are released outside the cell  Secretion: useful substances only  Expel waste products  Contractile vacuole: expels excess water that has accumulated within the cell

35. Movement across the membrane by:  Simple diffusion: materials move from an area of high concentration to an area of lower concentration.  Down or with the concentration gradient  Materials pass thru the lipid layers charges on the molecule (atom) limits diffusion  Concentration gradient ?

36.  Passive diffusion: no energy is needed.  Polar molecules have little or no charge on them so they diffuse easily.

37. 2. Facilitated diffusion  Channels or holes are present in the cell membrane.  Properties of the proteins that line the channels decide which ions can pass and how many.

38. Osmosis  The movement of water freely in or out of the cell.  When an equal number of ions is reached there will be no movement  High solute content = low water  Low solute content = high water  Passive: movement of water with the gradient (low solute=high water) low water = high solute

39.  Small materials pass thru the phospholipid bilayer  Aquaporin: water channel (slightly wider than a water molecule so passage is easy)

40. Active Transport  Taking in of substances even though there is a high concentration already.  Materials are moving against the gradient  Define concentration gradient?  This type of transport requires energy (ATP which is a result of cellular respiration)  Sometimes material is pumped out inspite of the concentration difference.

41.  Pump proteins carry out this type of transport (p38 note how it works)  P 39 and 40 Na K pump take notes.

42. Na/K pump Active transport Neurons  Nerve impulses involve the rapid movement of Na and K ion exchange.  3Na out and 2K in and this process uses 1 ATP  3Na enter the pump from inside the cell  The ATP causes the pump to change shape and close with the Na inside

43.  The pump opens to the outside and the 3 Na ions are released into the environment  2K from the outside( enter and attach to the binding site) ( release a phosphate from the ATP)  The pump changes shape and opens - allowing the K ions to pass into the axon.

44. Potassium pump (facilitated diffusion)  4 proteins with a narrow passage (material can pass either way)  The potassium is bonded to water which is too large to pass. The bonds must be broken and the K attaches to an amino acid.  K passes thru the membrane and reattaches to water, the amino acid will then block the opening

45. Voltage gated  More + outside (more – inside) the channels will be closed  More + inside (more – outside) the channels are open and rapidly close due to the presence of the amino acid.

46. Estimation of Osmolarity  = the total concentration of osmotically active solutes (These solutes are osmotically active: since they cannot pass through the membrane water has to move in order to equilibrate the osmotic pressures.)  ISOTONIC: same osmolarity as a tissue  HYPERTONIC : higher osmolarity Many dissolved solutes  HYPOTONIC : lower osmolarity fewer dissolved solutes

47. Preventing osmosis Hypertonic high osmolarityHypotonic low osmolarity  High solutes concentration low water. Water rushes from the cell causing it to shrink and crenellate  Low solutes concentration and high water. Water rushes into the cell causing it to swell and burst.

48. isotonicUses for normal saline  Water enters and leaves the cell at the same rate and no cell damage is seen  1. iv  2. wound rinsing  3. moisten skin  4. eye drops  5. frozen slush for organ transplant

49. The origin of cells  Cells are formed from pre existing cells the genetic information was copied so that the two new cells had a full set of DNA (genes)  The zygote was the first cell of our life.  Scientists claim to have created a cell, however it was formed from the genes of a bacterium and merely modified to create a new species of bacterium

50. Spontaneous generation  Formation of living organisms from nonliving matter.  Many experiments designed to test this theory. Redi, Spallanzani, Pasteur.  Cells are highly complex, no way has been thought of to produce cells from simpler subunits

51.  Cell division is the only way to increase the number of cells in an organism  Viruses are simpler subunits, they are not made of cells, they can only be produced inside a host cell that they have infected.

52. Origins of the first cell  Cells must have arisen from nonliving subunits.  Four hypothesis for the production of cells p48

53. Endosymbiosis and eukaryotic cells  Mutualistic relationship: both parties benefit  Natural selection favors the organism that can adapt and survive.

54. Endosymbiosis and eukaryotic cells  Cellular organelles (mitochondria and chloroplasts) were taken into larger cells thru endocytosis. (larger prokaryotes didn’t die)  They replicated themselves along or at the same rate as the larger cell (endosymbiosis)  Evolution now makes them a part of the cellular structure.  Symbiotic relationship: both organisms benefit from the contact.

55.  Symbiotic and mutualistic relationship are the same thing.  This same theory applies to the presence of chloroplasts within a plant cell (the produce photosynthetic energy for eukaryotes  See page 50 for a diagram  After much time these organelles are no longer capable of independent living.

56. Features of mitochondria and chloroplasts that suggest they were capable of independent living.  1.  2.  3.  4.

57. Cell division Role of mitosis  The cell divides into two daughter cells, each with its own identical nuclei to the other.  The DNA must be replicated (during interphase) (before mitosis begins)  Double DNA replicated called chromatids.

58. INTERPHASE  The number of mitochondria and chloroplasts (PLANT CELLS AND ALGAE) increase. Synthesizing material to add to the cell wall (protein synthesis)  G1 phase: cellular contents other than DNA are duplicated  S phase: chromosomes are duplicated

59.  G 2 phase: Growth and preparation for cell division (lower SA to V so the cell can become bigger)  G 0 phase: cells enter when they are not going to divide (temporary or permanent)

60. PROPHASE  Chromosomes undergo supercoiling (condensation) DNA becomes tighter and shorter more compact.  Nucleolus breaks down  Microtubules form from MTOC (microtubule organizing center) they will be linked to each pole of the cell.  End of phase nuclear membrane disappears. No nucleus can be seen, chromosomes are dispersed.)

61. METAPHASE  Microtubules grow and attach to centromere. Allows for the correct migration of the chromatids to opposite poles (sides of the cell)  Microtubules will shorten and contract, at this point if they are not attached the chromosome will remain in the center

62. ANAPHASE  Centromeres separate allowing for chromatids to separate.  Pulled rapidly by shortening of spindle fibers

63. TELOPHASE  Chromatids reached the poles now called chromosomes (uncoiled).  Pulled into a tight group and the nuclear membrane reforms around them.  Nucleolus reforms

64. CYTOKINESIS  Occurs when mitosis is complete. (starts a little before)  Animal cells plasma membrane pulls in forming a cleavage furrow.  Reaches the center pinches off and equal amounts of cytoplasm goes to each cell.

65.  Plants cells the 2 plasma membranes are formed across the equator of the cell (cytoplasm has been divided)  Cell plates form and build into new cell walls for each of the daughter cell.  Please go online and look for different pictures of mitosis so you can begin to distinguish one phase from the next

66. CYCLINS  These are proteins that make sure everything moves to the next stage when the prior stage is complete  Cyclin dependent kinase: an enzyme that will bind to the cycline and become active  This allows the cell to be specific to one stage at a time.

67.  Threshold concentration of cyclins is needed to proceed to the next level of mitosis  List the 4 cyclins and define what they do on the next slide

68. List the 4 cyclins and define what they do

69. Tumor formation  Tumor is any abnormal group od cells found in any part of the body at any age.  Benign tumor: the cells don’t spread and invade other tissues  Malignant when the tumor cells move to other tissues else where in the body. These are called secondary tumors.  The first tumor site is called the primary site.

70.  Carcinogen: any chemical agent that causes cancer.  Mutagens are carcinogenic (chemicals, uv light, high energy x rays) These cause mutations which result in the formation of cancer.  Several mutations are needed to form a tumor cell.

71.  The first tumor site is called the primary site ( first collection of tumor cells)  Metastasis : the movement of tumor cells to other tissues setting up a secondary site.

72. Smoking and cancer  Correlation: relationship between two factors  Positive correlation: one factor increases and so does the other  Negative correlation: one factor increases and the other factor decreases.  Correlation is a relationship  Cause definite proved connection between the two factors