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Unit 2 cells


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Unit 2 cells

  1. 1. Refer to Campbell and Reece, 2010 –Chapter 6 and 7 p. 96-123 and 125-131,Edulink and learning guide notes
  2. 2.  The study of cells and micro organisms haschanged over time with the change intechnology. These were studied in the beginning with handlenses, single lens microscope, light microscope Today we have electron microscopes. Two types of electron microscopes are usedtoday: SEM – Scanning electron microscopeand TEM – Transmission electron microscope.
  3. 3.  Developed a microscopewith one lens. Discovered- bacteria- blood cells- spermatozoa- protozoa
  4. 4.  Uses the concept cellfor the first time. He used it when helooked at themicroscopicstructure of corkcells.
  5. 5.  Describes the nucleus of a cell
  6. 6.  Developed the cell theory:- Plants and animals are made of groupsof cells.- The cell is the basic unit of livingorganisms
  7. 7.  Expanded the cell theory: He said that new cells formed by thedivision of existing cells
  8. 8.  Expanded the celltheory more: He said that all cellscan be traced to theirorigin
  9. 9.  All living organisms are made out of cells New cells are formed by the division ofexisting cells The cell houses genes, which are theblueprint for growth, functioning anddevelopment of cells The cell is the functional unit of lifebecause all chemical reactions of life takeplace inside the cell
  10. 10.  A cell is the basic unit ofstructure and function inorganisms. Cells differ in size, shape and infunction. A cell consist of smallerstructures called organelles.
  11. 11.  Prokaryotic or Eukaryotic cells. Only organisms of the domains Bacteriaand Archaea consist of prokaryotic cells –cells without a membrane bound nucleus. Protists, fungi, animals and plants allconsist of eukaryotic cells – cell with amembrane bound nucleus.
  13. 13. Chapter 6 p. 98 – 131
  14. 14.  Porous Varies in thickness Consist of pectin (elasticity), cellulose fibrilsheld together with non-cellulose substances(hardens the cell when mature) and lignin(adds strength to cell especially in woodyplants) Cell wall is permeable and protects the insideof the cell. Middle lamella (layer of adhesive substances) –holds the cells together Plasmodesmata (pores) that connects thecytoplasm of the connecting cells – selectivelypermeable
  15. 15.  Consist of 2phospholipid layersand proteins inbetween. The phospholipidlayers are parthydrophillic andpart hydrophobic
  16. 16.  +/- 5µm, largest organelle in cell. Enclosed by a nucleomembranewith nuclear pores. Function:Protection and add to selectivepermeability. Filled with nucleoplasma, anucleolus and chromatin. Functionof chromatin: carries geneticmaterial in the form ofchromosomes. Function of nucleolus: Produce r-RNA
  17. 17.  Consist of 2 membranes: Outer –and a highly convoluted innermembrane- These folds arecalled cristae – they increase thesurface area. Filled with matrix called stromathat contains DNA andribosomes. Function: Produce energy in theform of ATP by means ofcellular respiration
  18. 18.  Enclosed by a doublemembrane Filled with stroma andthylakoids filled withchlorophyll arranged ingroups called grana. Ribosomes and starch grainsin stroma. Function: Photosynthesis
  19. 19.  Membranous sac Filled with cell sap. Causes turgor pressure in thevacuole. Function: Stores varioussubstances, including waste. Helps with osmotic potential ofcell.
  20. 20.  Endoplasmic Reticulum – Transportsystem in cell Ribosomes – Protein synthesis Golgi-apparatus – Make lysosomes andacts as transport system. Lysosomes – Intracellular digestion. Plastids e.g.– Leucoplasts – Storesstarch- Chromoplast – gives colourto flowers and fruit.* Centrioli – Mitosis in animal cells
  21. 21.  The cell membrane has the ability toregulate transport molecules acrossits structure. This function is essential to the cell’sexistence. The fluid mosaic model helps toexplain how membranes regulate thecell’s molecular traffic.
  22. 22.  Hydrocarbons, carbon dioxide andoxygen – non-polar So they can dissolve in the lipid bilayer ofthe membrane. They can cross the membrane withoutthe aid of membrane proteins. Polar molecules like, water and glucosemove slowly across the membrane andneed the aid of proteins to get acrossthe membrane.
  23. 23.  Hydrophyllic substances can avoidcontact with the hydrophobic lipid bilayerby passing through transport proteins thatspan the membrane. Channel proteins – tunnel for polarmolecules to pass through membrane Aquaporins – channel proteins for thetransport of water
  24. 24.  Carrier protein: Hold onto solutes thatwant to move across the membrane andchanges shape as it moves through themembrane. Each carrier protein is specific to what ittransports.
  25. 25.  The microscope is an instrumentdesigned to observe objects too small tobe seen with the naked eye. The human eye cannot distinguishobjects much smaller than 0.1mm. The microscope act as an extension ofthe eye, allowing one to see smallerobjects.