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Early beginnings 1665 - Robert Hooke - described “cells” 1676 - Leuwenhoek - described microbes 1683 - Leuwenhoek - published first drawings of bacteria.

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Presentation on theme: "Early beginnings 1665 - Robert Hooke - described “cells” 1676 - Leuwenhoek - described microbes 1683 - Leuwenhoek - published first drawings of bacteria."— Presentation transcript:

1 Early beginnings Robert Hooke - described “cells” Leuwenhoek - described microbes Leuwenhoek - published first drawings of bacteria from the mouth

2 “Cell theory” 19th century Schlieden (botanist) & Schwann (zoologist) Cell Theory –organisms composed of one or more cells –the cell is the smallest unit of life –continuity of life is from the growth and division of cells

3 Basic cell Common features of prokaryotic and eucaryotic cells –Plasma membrane –DNA –Cytoplasm

4 Prokaryotes Pro - “before” & karyote - “nucleus” –no nucleus plasma membrane cell wall capsule flagella pili

5 Eucaryotes Eu - “true” & caryote - “nucleus” –contain a nuclear membrane bound nucleus plasma membrane cytosol cytomembrane system –Endoplasmic reticulum –Golgi bodies –Vesicles

6 Plasma membrane Barrier between the outside world and the inside world of the cell composed of phospholipids arranged in a bilayer (see Figure 11.11)Figure Selectively permeable

7 Phospholipid bilayer

8 Cytoskeleton Figure 1.20 Structure –Actin, intermediate filaments, microtubules –Protein Function –Structural integrity –Organization –Motility

9 Cytoskeleton

10 Mitochondria Figure 1.11 “Cellular Power Plant” Structure –Double membrane -outer membrane & inner membrane Function –Oxidize food to produce ATP –Site of aerobic respiration

11 Mitochondrion

12 Chloroplast Figure 1.13 Structure –double membrane - outer membrane & thylakoid membrane Function –Site of photosynthesis

13 Chloroplast

14 Central Vacuole Plants only Structure –Membrane bound Function –Storeage

15 Summary Nucleus - localize chromosomes ER –sER - synthesize lipid –rER - assemble polypeptides Golgi bodies - modify and transport protein and lipids Vesicles - transport Mitochondrion - synthesize ATP

16 Non - membranous structures Ribosomes - assemble polypeptides Cytoskeleton –Structural –Organizational –Motility

17 Light microscope Brightfield microscopy –illumination source - light –resolution proportional to 1/2 wavelength –practical resolution > 500nm –usually requires some type of staining –see Panel 1.1Panel 1.1

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19 Brightfield microscopy Variations –Darkfield object appears bright on a dark background –Phase contrast can view organelles without staining –see Panel 1.1Panel 1.1

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21 Fluorescent microscope Source of illumination - UV light or short wave visible wavelengths Requires a fluorochrome stain Excitation wavelength - UV Emission wavelength - longer wavelength –usually in visible light range See Panel 1.1Panel 1.1

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23 Electron microscope Source of illumination - electron beam Types of electron microscopes –transmission - TEM resolution 2nm see Panel 1.1Panel 1.1 –scanning - SEM resolution 3-20nm See Panel 1.1Panel 1.1

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26 Newer microscopes Confocal microscope –uses laser light to “virtually” dissect specimen Atomic Force Microscope –Extremely high resolution –can view living organisms –Website hapter3/Chapter3.html hapter3/Chapter3.html

27 Cell size Small spheres have a greater surface area to volume ratio (SA:V) than large spheres Surface area to volume ratio influences exchange of nutrients and waste products from a cell. The smaller the SA:V, the greater the rate of exchange!


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