This document summarizes key characteristics and features of bacteria from the domain Eubacteria. It outlines that bacteria are unicellular prokaryotes found everywhere that lack nuclei and have cell walls without cellulose. Bacteria can be motile using flagella or pili and have various cellular structures including cell membranes, capsules, cytoplasm, and endospores. Bacteria can be both beneficial and harmful to organisms, playing important roles in ecosystems, industries, and human health.

2. Kingdom Eubacteria (True Bacteria)
Bacteria are located everywhere – air, water,
land, and living organisms including people.
General Characteristics:
1. All are unicellular (one-celled structural level)
2. All are prokaryotic - cells that lack nucleus
(no nuclear envelope) (PRO = NO nucleus)
3. All have cell walls – NO cellulose in cell walls
4. Can live in both aerobic (with O2) and
anaerobic (without O2) environments

3. Ex: Streptococcus Ex: Lactobacillus Ex: Spirillium

5. •Motility - movement
•Swarming occurs with some
bacteria
•Arrangement basis for classification
•Monotrichous; 1 flagella
•Lophotrichous; tuft at one end
•Amphitrichous; both ends
•Peritrichous; all around bacteria
Flagella

7. Pili
•Short protein appendages
smaller than flagella
•Adhere bacteria to surfaces
•F-pilus; used in conjugation
Exchange
ofgenetic
information

8. Cell Membrane
•Bilayer Phospholipid
•Water can penetrate
•Flexible
•Not strong, ruptures easily

9. Capsule or Slime Layer
•Glycocalyx - Polysaccharide on
external surface
•Adhere bacteria to surface
•Prevents Phagocytosis

10. Cytoplasm
•80% Water {20% Salts-
Proteins)
•DNA is circular, Haploid
•Plasmids; extra circular DNA
•No organelles (Mitochondria,
Golgi, etc.)

11. Endospores
•Resistant structure
(Heat, irradiation, cold)
•Takes time and energy to make
spores
•Location important in classification
(Central, Subterminal, Terminal)

12. Causes Disease by:
1. Destroying cells of infected organisms
by breaking the cells down for food.

14. D. Importance:
1. Beneficial
a. breakdown dead matter to
recycle nutrients into
ecosystem - decomposers

15. b. dairy industry - bacteria in
yogurt, sour cream and cheese
c. Oil spills - bacteria can digest small oil
spills

16. d. Genetic
engineering—
Recombinant/synthetic
DNA (Ex: Insulin)

17. e. symbiotic relationship - E. coli and our
intestines-both organisms benefit
Example: E. coli in intestines helps us digest food
and make vitamins (such as Vitamin K and
B-complex) In return, human intestines
provide food and shelter for bacteria.
(This strain of
E. coli is
different from
the E. coli
strain that
causes food
poisoning.)

18. Harmful :
a. human diseases –
strep throat, tuberculosis,
tooth decay and bad
breath, anthrax, plague,
tetanus, food poisoning
Tetanus
Strep Throat
Anthrax

19. b. food spoilage and poisoning – caused by
Salmonella and Staphylococcus
c. Treated with antibiotics – Some bacteria are able
to survive in presence of antibiotics that kill
other bacteria – antibiotic resistant bacteria
Note: This is why doctors tell you to take the entire
amount of medicine given even if you start to feel better
because if not, bacteria will have the chance to evolve and
become antibiotic resistant.

20. G+ve
•Thicker cell wall
•Teichoic Acids
1.Glycerol, Phosphates, & Ribitol
2.Attachment for Phages
G-ve
Endotoxin – LPS
Gram+ve and Gram -ve
(1.Lipid A
2. Polysaccharide)

21. THANK YOU