1. Bacteria

2. What are bacteria Prokaryotes
Cell membrane is surrounded by a cell wall
Chromosome is a single strand of DNA
No mitochondria, chloroplasts, nuclear membrane………

3. Bacterial Structure
Typical size: 1-10 micromenter ( micrometer for eukaryote cells)
Single circular chromosome (DNA)
Cell membrane made of protein and lipids
Cell wall present
Sometimes plasmids present

4. Bacterial Cell Wall Composed of complex carbohydrate and peptidoglycan
Functions to regulate transport (molecules that flow in and out of the cell)
Bacteria are identified based on their cell walls

5. Hans Christian Gram and His Stain
Cell walls with carbohydrate take up the stain that Gram invented
These cells are purple under a light microscope
They are called Gram-positive bacteria
Cell walls with carbohydrate and lipids do not take up Grams stain
These cells are not purple under a light microscope
These are Gram-negative bacteria
Infection with Gram-negative bacteria is usually very serious

6. Structure and Function
Cell classified by shape
Bacillus (bacilli) are rod shaped
Coccus (cocci) are spherical
Spirillum (spirilli) are spiral shaped
Nutrition and metabolism
Energy capture (page 582)
Metabolism (page 583)

7. Two Kingdoms of Bacteria
Eubacteria
Archaebacteria
Classification based on differences in ribosomal RNA

8. Eubacteria Largest group of bacteria Found everywhere
Diverse ecology and biochemistry
Some are photosynthetic, free living in soil, parasitic

9. Archaebacteria Ancient bacteria
Live in extreme environments (extremeophiles)
Many survive in the absence of oxygen
Cells walls lack peptidoglycan

10. Growth and Reproduction
Binary Fission
Conjugation
Spore formation

11. Binary Fission Cell doubles in size Chromosome replicates
Cell splits into two identical daughter cells
No exchange of genetic information
This is asexual reproduction

12. Conjugation Protein bridge forms between two cells
Some DNA exchanged between the cells
Cells incorporate the new DNA, chromosome replicates
Cells divide
This is a form of sexual reproduction

13. Sporulation
Form a structure called a spore when environmental conditions are adverse
Spore encloses some cytoplasm and the DNA
Spore resists heat, drying, desiccation, radiation, and chemical disinfectants
Spore survives for years
When conditions are better the spore “hatches” and the bacteria can grow again

14. Bacteria and disease
Pasteur found the link between bacteria and disease
Strep throat, diphtheria, tuberculosis, typhoid, tetanus, syphilis, gonorrhea, cholera, lyme disease, bubonic plague, food poisoning, botulism

15. Bacteria cause disease in two ways
Attacking cells and tissues of the body directly, using cells and tissues for nutrients
Producing toxins which in turn interfere with functions in the body
Fighting disease
Vaccination
Antibiotics