 The disadvantage of the SEM is  A. able to view living things  B. Electron beams have much shorter wavelengths than beams of light.  C. more diffraction in SEMs causing poor resolution  D. specimens must be chemically preserved and prepared.

 Describe to ways in which prokaryotes and eukaryotes are similar.

 Both are surrounded by a cell membrane  Both contain genetic material - DNA

 BIG Question: How do cells perform their functions?  1. QoD and DO NOW  2. Review Section 7-1 Guided Notes  3. Discuss Section 7-2  4. Begin classwork on cell structures  5. HOMEWORK and Review CH 2 TESTS  6. YOU will have a short QUIZ this week on Sections 7-1 and 7-2  7-1 NOTES and Cell Booklet Requirements posted on webpage!!!

CHAPTER 7

 The CELL is the basic unit of structure and function in living things.  CELL THEORY states ◦ 1. All living things are composed of cells ◦ 2. Cells are the basic units of structure and function in living things ◦ 3. New cells are produced from living cells

 1. Robert Hooke – viewed a thin slice of cork with an early compound microscope (1665) ◦ Name them cells because of a monastery’s tiny rooms. 2. Anton van Leeuwenhoek - observed tiny organisms in drops of pond water (1674) 3. Matthias Schleiden – Concludes that all plants are made of cells (1838) 4. Theodor Schwann – Based upon Schleiden’s work, concludes animals are living so all animals are also made up of cells (1839)

 5. Rudolph Virchow – proposes that all cells come from existing cells completing the cell theory (1855)  6. Lynn Margulis – idea that certain organelles were once free living organisms ◦ Mitochondria and chloroplast both contain their own DNA. ◦ Endosymbiont Theory – Prokaryotic organisms (mitochondria and chloroplasts) were once free living but began a symbiotic relationship with larger multi-cellular organisms.

 Follow molecules through cells using fluorescent labels and light microscopy  Build 3-D models with confocal light microscopy ◦ Scans cells with a laser beam  Produce movies of cells as they grow, divide, and develop with High-resolution Video Technology

 Light microscope –resolution of image limited ◦ Unable to visualize tiny structures  Electron microscope – electron wavelengths much shorter than light wavelengths ◦ View details up to 1000x smaller than light microscope images TEM (Transmission electron microscope) – explores cell structures and large protein molecules SEM (Scanning electron microscope) – scans surface of a specimen. 3-D images. Must be in a vacuum and specimens must be preserved Unable to study living things

 Scanning probe microscope – traces the surface of a sample. ◦ Able to observe single atoms ◦ Can operate in open air ◦ Show samples in solution ◦ Study surfaces ◦ Image DNA, Protein molecules, and other important biological structures

 Both are surrounded by a cell membrane  Both contain DNA – the molecule that carries biological information

 Do not contain a nucleus  Smaller and simpler  Genetic material is free floating within the cell  Grow, reproduce, respond to environment, and some can move along surfaces or swim through liquids  Examples are bacteria

 Contain a nucleus that contains DNA separate from rest of cell  Larger and more complex  Dozens of Highly specialized membranes and structures  Single celled to large complex multi-cellular organisms  Plants, animals, fungi, and protists (algae)