Light micrograph Scanning electron micrograph Paramecium
Cell Membrane Transmission electron micrograph Scanning electron micrograph
Which of these can be seen with an electron microscope but not a light microscope? 1.Human cells 2.Bacteria 3.Protein molecules 4.Amino acids
Discuss and write down your ideas: How did the invention of the microscope change the human view of the world? How did the invention of the electron microscope change our understanding of cells? WORKTOGETHERWORKTOGETHER
Eukaryotic Features Cells contain membrane-bound organelles. Nucleus holds multiple strands of DNA, which condense into chromosomes during cell division. May be single-celled or multi-cellular organisms.
Leucoplasts and other plastids starch globules 0.5 micrometer plastid
What do chloroplasts do? 1.Make energy 2.Use energy to make molecules. 3.Break sugar down to release energy.
Chloroplasts carry out photosynthesis to make sugars and other monomers. What does the plant use these monomers for? WORKTOGETHERWORKTOGETHER
One-celled Eukaryotic organisms have unique challenges. A Paramecium must: ingest food excrete waste sense and respond to the environment
(a) Cilium (b) Flagellum propulsion of fluid return strokepower stroke plasma membrane direction of locomotionpropulsion of fluid continuous propulsion
cilium Paramecium 0.1 micrometer protein "arms" central pair of microtubules section of cilium (transmission EM) basal body plasma membrane
contractile vacuole full reservoir contracted reservoir
pore collecting ducts central reservoir Reservoir contracts, expelling water through pore. Water enters collecting ducts, fills central reservoir.
In a one-celled organism, which organelle is most like: A stomach (assists with digestion)? A kidney (removes excess water)? WORKTOGETHERWORKTOGETHER
Recap Prokaryotic cells have no membrane- bound organelles. Eukaryotic cells have membrane-bound organelles, which compartmentalize processes for better efficiency. ALL cells have a cell membrane and DNA.