In The Beginning….

1. In The Beginning…. The Origin of Life

2. Chapter 17 The Origin and Evolution of Microbial Life: Prokaryotes and Protists

3. Chapter 17.1 Life Began on a Young Earth

4. Chapter 17.2 How Did Life Originate?

5. Chapter 17.3 Stanley Miller’s Experiments Showed That Organic Molecules Could Have Arisen on a Lifeless Earth

7. Chapter 17.4 • The First Polymers May Have Formed on Hot Rocks or Clay

8. Chapter 17.5 • The First Genetic Material and Enzymes May Both Have Been RNA

10. Chapter 17.6 • Molecular Cooperatives Enclosed by Membranes Probably Preceded the First Real Cells

12. Chapter 17.7 Prokaryotes Have Inhabited Earth for Billions of Years

13. Shadows

14. Chapter 17.8 Archaebacteria and Eubacteria are the Two Main Branches of Prokaryotic Evolution

15. Three Domains • The current system, the Three Domain System, groups organisms primarily based on differences in ribosomal RNA structure. Ribosomal RNA is a molecular building block for ribosomes. • Archaea, Bacteria, and Eukarya

16. Six Kingdoms of Life • Animalia - humans, dogs, worms • Plantae - trees, plants, most algae • Fungi - mushrooms, yeast • Protista - amoeba, paramecium • Eubacteria – most bacteria, blue-green algae (domain bacteria) • Archaebacteria – extreme environment bacteria • (domain archae) Domain Eukarya

17. Eubacteria • Unique RNA sequences • Simple RNA polymerase • No Introns in DNA • Peptidoglycan • Membrane lipids unbranched • Sensitive to antibiotics • Archaebacteria • RNA sequences match eukaryotes • Complex RNA polymerase • Introns in DNA • No peptidoglycan • Membrane lipids branched • Not sensitive to antibiotics

18. Chapter 17.9 Prokaryotes Come in a Variety of Shapes

20. Chapter 17.10 Prokaryotes Obtain Nourishment in a Variety of Ways

21. Prokaryotic modes of nutrition

22. Chapter 17.11 The First Cells Probably Used Chemicals for Both Carbon and Energy

23. Two leading hypotheses for early energy metabolism: • Obtain ATP from the environment • Turn ADP into ATP using sulfur and iron compounds • chemiosmosis

24. Antonie Van Leeuwenhoek • Father of microscopy • Perfected lens making (1600’s) • Calculus between teeth had “little beasties” - no one believed • First to see bacteria

25. Robert Hooke • Looked at cork - not alive (1600’s) • Only saw cell walls • Looked like rooms monks lived in • Coined the word “cell” • micrographia

26. Robert Brown • Botanist - 1800’s • First to see nucleus • Nucleus was stained dark

27. The Cell Theory • Theodor Schwann - zoologist • Rudolf Virchow - physiologist • Matthias Schleiden - botanist • 1. The cell is the basic unit of life • 2. All organisms are made of cells • 3. Cells come from cells (life from life)

28. Prokaryotes • No membrane bound nucleus • DNA in circle • DNA not associated with proteins • No organelles except ribosomes • Eukaryotes • Membrane bound nucleus • DNA is linear • DNA wound around spools of proteins • Membrane bound organelles

29. Prokaryotes • Many are anaerobes • All single celled • All Rxn occur in cytoplasm • Small cells • Eukaryotes • All are aerobes • Many are multicelled • Diverse Rxn in organelles • Many are large

30. Chapter 4.1 Microscopes Provide Windows to the World of the Cell

31. 3 types: 1. Light microscope (Phase/Contrast) 2. Transmission Electron Microscope (TEM) 3. Scanning Electron Microscope (SEM) Magnification: The enlarging of an image. Resolution: The power to show detail clearly. Resolving power is the ability to distinguish objects from one another. Micrograph: Photograph of an image formed with a microscope.

32. Light Microscope: Refracted (bent) light rays magnify the image. Specimen must be thin enough for light to pass through, used to see living cells. Can use stains but cell will die and sometimes its structure is altered. Wavelengths of visible light (400-700 nm on electromagnetic spectrum) limits resolution – maximum detail is only .2 μm. Maximum magnification is about 2,000x.

33. Phase/Contrast Microscope: Same as light microscope only it converts small differences in structure to large variations in brightness. Also used to see living cells. Same magnification and resolving limits as a regular light microscope.

34. TEM: Uses electrons with wavelengths of .005nm (100,000x shorter than visible light) Magnetic field acts as a lens, diverting electrons along defined paths and channels them to a focal point. Electrons must travel in vacuum, thus cells must be dead. Cells must be thin, electrons scatter in patterns according to density. The darker the area, the more dense.

35. TEM: High voltage excites electrons until they are 10x more energetic and can easily pass through specimen and show internal structures. Cells must be stained with heavy metal dyes. Max resolution is .2nm. Max magnification is 2,000,000x.

36. SEM: Uses a narrow beam of electrons to scan the surface of specimen. Specimen must be coated with a thin metal layer (no living cells). Stops electrons from passing through specimen. Metal responds by giving off some of its own electrons. A television screen shows the image by detecting emission patterns.

37. SEM: Gives image of specimen depth, you get a 3D image. Max resolution of 10nm. Max magnification of 50,000x.