1. Bacteria Bacteria on the tip of a pin

2. Prokaryotes Identified by their • Shapes • Chemical nature
of their cell walls
• The ways they
move
obtain energy

3. Basic Structure
Cell wall – protects the cell & gives it shape.
Outer membrane – protects the cell against some anibiotics (only present in gram-negative)
Cell membrane – regulates movement of materials into & out of the cell; contains
enzymes important to cellular respiration.
Plasmid – circular piece of DNA that contains some genes obtained through genetic recombination.
Capsule & Slime layer – protect the cell & assist in attaching the cell to other surfaces.

4. 3 basic shapes
Bacillus
Coccus
Spirilla

5. • Cell Arrangements
– Diplo – cells are paired
– Staphylo – cells are in
grape-like clusters
– Strepto – cells are in
long chains

6. Cell Wall • Two different types of cell walls are found in eubacteria • Gram staining helps to tell them apart using two different types of dye – Violet - primary stain – Red - counterstain

7. • Gram positive – Bacteria cells containing peptidoglycan absorb only the violet dye – Appear purple in the microscope • Gram negative – Bacteria with a second(outer) layer of lipid and carbohydrate molecules – Extra layer absorbs only the red stain – Appear pink in the microscope

8. Gram Staining Bacteria • Gram Positive – stains purple • Gram Negative – stains pink

10. Growth and Reproduction
Binary Fission: bacterium doubles in size, it replicates its DNA and divides in half.
Is this sexual or asexual reproduction?

11. Growth & Reproduction- Conjugation
the process by which two living bacteria bind together and one bacterium transfers genetic information to the other.
Sex pili

12. Growth and Reproduction…
Endospore – protects the cell against harsh
environmental conditions, such as heat and drought.
May allow the bacterium to survive for thousands of years.

13. Bacillus cereus

14. Bacillus cereus (found in soil)
straight rods, arranged singly or in pairs
cells stain Gram-positive (blue-violet)

15. Aquaspirillum serpens

16. Aquaspirillum serpens
(found in fresh water)
-spiral shaped, arranged singly
-cells stain Gram-negative (red)

17. E. Coli

18. Escherichia coli (digest food in your intestines)
straight rods, arranged singly or in pairs
cells stain Gram-negative (pink)

19. Staphylococcus Epidermidis

20. Staphylococcus Epidermidis
epidermis (found normally on skin)
spherical shape
cells stain Gram-positive (blue-violet)