1. Cells The history of cell research & an in-depth look at the internal organization of cells

2. History of Cells 1665 – Robert Hooke –Coined the term – “cells” Cork Tissue –Dead plant cell walls 1675 – Anton VanLeeuwenhoek –More advanced microscope Pond H 2 O – animalecules –Single-celled organisms

3. How did Scientists study Cells? Observation through magnifying lenses Measured surface area & volume Drew pictures/labled Published materials, sizes & pictures

4. Compound Light Microscopes Artificial/Reflected light 1 or more lenses Magnification increases size (2000x) Resolution – measure of clarity

5. Electron Microscope Shorter wavelength of light – electrons Magnify – 200,000x Electron beam & specimen (vacuum) TEM – Transmission –Metal ions: e show image;fine detail. –SEM: Scanning; thin layer of metal, e bounce; shows 3-D image

6. Cell Features

7. The Cell Theory Matthias Schleiden –German botanist, 1838 –All livings things are made up of cells Theodore Schwann –German zoologist, 1839 –Cells are the basic units of structure & function in all living things Rudolph Virchow –German physician, 1858 –All cells come from pre- existing cells http://mitglied.lycos.de/worldofwaldi/virchow/bio_page1.html home.tiscalinet.ch/biografien/ biografien/schleiden.htm www.uku.fi/laitokset/anat/ sob/soluhist4.htm

8. Cell Size Small is better than large Humans have 100 trillion cells. Range: 5 um to 20 um. Substances can enter a number of cells faster than large cells. –High surface area-to- volume ratio.

9. Prokaryotic Cells vs Eukaryotic Cells

10. Prokaryotes No nucleus or internal compartments Single-celled organism No specialized functions- just life. Mostly bacteria DNA – single circular molecule Cell wall-structure and support Most have flagella for movement.

11. Eukaryotes Contain nucleus & other internal compartments (organelles) Organelles-structural components that perform all complex cell functions DNA-found in nucleus (chromosomes) Found in multicellular organisms. Cytoskeleton- internal support structure.

12. Animal Cell Nucleus Nucleolus Rough Endoplasmic Reticulum Smooth Endoplasmic Reticulum Ribosomes Golgi Bodies Mitochondria Cell Membrane Cytoplasm

13. Plant Cell Cell Membrane Vacuole Chloroplasts Cell Wall Nucleolus Nucleus Rough ER Smooth ER Golgi Bodies Mitochondria Ribosomes Cytoplasm

14. Comparing Plant and Animal Cells PlantAnimal

15. Cell Organelles

16. The Nucleus Found in eukaryotic cells ONLY Control center of the cell Nuclear envelope is selectively permeable - pores www.dartmouth.edu/.../ bio4-lectures/theCell.html

17. Ribosomes Site of protein synthesis in all cells Some are attached to ER – rough ER Some are “free” and roaming around the cell www.esb.utexas.edu/.../ chapter07/chapter7.htm

18. Endoplasmic Reticulum (ER) Subway system of the cell – move proteins and other substances throughout cell Rough & Smooth ER Smooth ER – makes lipids & detoxifies substances www.ualr.edu/ ~botany/images.html

19. Packaging & Distribution of Proteins Golgi Apparatus –Flattened, membrane bound sacs –Enzymes modify proteins –Modified proteins become enclosed in vesicles - transport Lysosomes –Spherical organelles –Function in digesting products for the cell –Recycles the cell’s used components

20. Mitochondria “Powerhouse” of the Cell Takes food energy and converts it into cellular energy = ATP Cells that need a lot of energy, have a lot of mitochondria micro.magnet.fsu.edu/.../ mitochondria.html

21. Cell Membrane

22. Cytoskeleton Cell skeleton –Protein fibers anchored to the plasma membrane –Support the shape of the cell –3 types of fibers - Microfilaments - Microtubules - Intermediate fibers

23. Cytoskeleton Fibers Microfilaments –Protein: actin –Just beneath the plasma membrane –Give the cell its shape Microtubules –Information highway –Act as traintracks –RNA transport Intermediate Fibers –Framework for enzyme & ribosome confinement –Organization of metabolic activities

24. Fluid Mosaic Model of the Cell Membrane

25. Cell Membrane Phospholipid Bi-layer –Two layers made up of a phosphate group and 2 fatty acid tails. –Polar heads (hydrophillic) –Nonpolar tails (hydrophobic) Selectively Permeable –Allows only certain things across membrane. –Repels polar objects except H 2 O and O 2 –Allow non-polar substances to pass freely (Small) Membrane Proteins –Cell surface markers –Receptor Proteins –Transport Proteins

26. Nonpolar Lipids do not carry a charge Permeable to nonpolar substances –O 2 & CO 2

27. Passive Transport Does not require any ENERGY Substances move down their concentration gradient Move through membrane or through protein channels

28. Passive Transport 3 Types –Diffusion Movement of substances from a higher conc. to a lower conc. –Osmosis Movement of water from a higher conc. to lower conc. –Facilitated Diffusion Movement of larger or polar (charged) molecules from a higher conc. To lower conc.

29. Tonicity Tonic = concentration Isotonic – solute concentration inside and outside cell are equal Hypertonic – solution outside of cell has a higher solute concentration Hypotonic – solution outside of cell has a lower solute concentration Osmotic Pressure – net movement of water into or out of a cell produces this force

30. Active Transport Requires ENERGY Movement of substances AGAINST their conc. gradient –Example: Sodium/Potassium Pump

31. Types of Cell Membrane Transport

32. Homeostasis at the Cellular Level Unicellular Organisms –Grow, respond, transform energy & reproduce Multicellular Organisms –They are all interdependent –Cell Specialization – groups of cells will become unique and perform a particular task(s) that are important to maintain the overall individual.

33. Cellular Communication Chemical Signals –Receptor sites on certain cells specific for an ion or chemical (hormone) Cellular Junctions –gaps that are connecting adjacent cells –Transfer of goods or simple communication –Heart cells – electrical stimuli keep heart in a rhythmic pattern

34. Levels of Organization in Multicellular Critter Organism –Organ Systems Organs –Tissues »Cells