1. Research III & IV Packet #3

2. Introduction to Microorganisms Recall the Cell Theory – All living things are composed of cells Recall from the Characteristics of Life – Energy Utilization Cells/Organisms will metabolize – Metabolism » Combination of Anabolism and Catabolism  Anabolism  Simple substance to a complex  Catabolism  Complex substance to a simple

3. Cells  Fall under two major categories  Prokaryotes  Eukaryotes

4. Prokaryotes  Kingdoms Archaebacteria & Eubacteria  No membrane bound organelles  No nucleus  Ribosomes are present  30 S (Subunits)  60 S  Contains polyamines and magnesium  Contain plasmids that have 7 – 8 genes  Plasmid  Small ring of DNA that carries accessory genes separate from those of a bacterial chromosome  Also found in some Eukaryotes  Yeasts

5. Prokaryotes II  Chromosome does not contain histones  Histone  Small protein that binds to DNA due to ionic bonds  DNA negative charged  Protein positively charged  No mitotic division  How do prokaryotes reproduce?  Binary Fission is most typical of bacteria and protists

6. Exchange of Genetic Material Plasmids II  Plasmids  Categories  F plasmid  Fertility factor  Found in bacteria  F + when plasmid is present  F - when plasmid is absent  Allows bacteria conjugation

7. Exchange of Genetic Material Plasmids III  R Plasmid  Resistance Plasmid  Carry genes that provide resistance to various antibiotics  Chloramphenicol, tetracycline and penicillin  Carry genes that provide resistance to heavy metals  Arsenic and mercury  Generally, plasmids carry genes that code for functions not essential for cell growth  The chromosome carries the genes that code for those functions

8. Exchange of Genetic Material Transformation  Genetic alteration of a cell resulting from the introduction, uptake and expression of foreign material (DNA)  Discovered by Fredrick Griffith while searching for a vaccine against bacterial pneumonia’

9. Exchange of Genetic Material Bacterial Conjugation  Bacterial Conjugation  The transfer of genetic material between bacteria through cell to cell contact  Incorrectly regarded as the bacterial equivalent of sexual reproduction or mating  Does not involve the fusing of gametes and the creation of a zygote

10. Exchange of Genetic Material Transduction  Transduction  Process by which bacterial DNA is moved from one bacterium to another by a virus (bacteriophage)  Two Cycles  Lysogenic Cycle  The bacteriophage chromosome is integrated into the bacterial chromosome  Can remain dormant for thousands of generations  If the lysogen, UV light for example, is induced, the phage genome is excised (removed) from the bacterial chromosome and the 2 nd cycle, the Lytic Cycle, is initiated  Lytic Cycle  Results in the lysis (breaking down) of the cell  Release of phage particles  Leads to the production of new phage particles which are released by lysis of host

11.  When the viral genetic material is activated, viruses start to replicate.  The more viruses that are produced, the more saturated the bacterial cell becomes.  Eventually, the bacterial cell bursts--like a balloon  All the viruses are released  Those newly released viruses will look for a new host--a new bacterial cell  The process repeats --lysogenic to lytic cycle

12. Eukaryotes I  Kingdoms  Protista  Fungi  Plante  Animalia  Cell wall present in fungi and plants  Membrane bound organelles  Nucleus exists  Ribosomes  80 S (subunits)  Attached to the Endoplasmic Reticulum  70 S (subunits)  Found in the mitochondria

13. Eukaryotes II  Choloroplasts found in plants  Cell walls, if present, do not contain peptidoglycan  Respiration occurs in the mitochondria  Cell Respiration  Chromosomes have histones  Mitotic and/or Meiotic division exists  Kingdom Eubacteria  Known as the disease causing agents

14. Characteristics of Bacteria  Respiration  Aerobic Respiration  Use of oxygen  Anaerobic Respiration  Respiration without oxygen  Shapes  Cocci  Spherical shape  Stick together in chains  Streptococcus  Stick together in clusters  Staphlococcus  Bacilli  Rods  Spirilla  Spiral shaped

15. Characteristics of Bacteria Obtaining Energy  Autotrophs  Chemoautotrophs  Obtain energy from the oxidation of inorganic materials and use this energy to synthesize their own foods  Photoautotrophs  Use energy from sunlight for the manufacturing of food  Hetereotrophs  Obtain energy from the oxidation or breakdown of living or non-living organic material  They are parasitic, saprobionic or mutualistic

16. The Cell Wall Gram Negative vs. Gram Positive  The Cell walls will contain a glycoprotein  However, in some walls, the glycoprotein is supplemented by large molecules of lipopolysaccharides  Such walls are NOT stained by gentian (crystal) violet and are said to be Gram-negative  Those without the lipopolysaccharide are said to be Gram- positive  Gram-positive bacteria are more susceptible to antibiotics and lysozymes than Gram-negative bacteria