1. Bacteria TEST: 11/6

2. What are bacteria? Prokaryotes Microscopic (nanometers!) No nucleus
Circular DNA (not chromosomes)
Few organelles
Microscopic (nanometers!)
Plasmids:
-circular DNA
fragment
-additional genes
-provide resistance
and/or adaptations

3. Classification Kingdom Eubacteria Kingdom Archaebacteria Staph
Normal bacteria
Found everywhere
Cell wall of peptidocylcan
EX: E. coli, staph
Kingdom Archaebacteria
Extremophiles; ancient
Live in extreme conditions
Cell wall lacks peptidoglycan
EX: Methanogens
Staph

4. Multicellular organisms
Bacterial Evolution
Prokaryotes were first in fossil record
Change in Earths atmosphere
Presence of O2 allowed bacteria to diversify
1st living organism
Archeobacteria
(chemosynthetic)
3.8 BYA
2 BYA
Eukaryotic cell
Complex cells
Life forms diversify
1 BYA
Multicellular organisms
3 BYA
Photosynthesis
O2 level increased
4.5 BYA
Earth formed

6. Still Successful on Earth after 3.5 Billion Years!
Variety & Diversity in Both Domains
Still Successful on Earth after 3.5 Billion Years!

7. Bacteria Identification
3 methods to identify a bacteria:
Shape
Cell Wall
Movement
Petri dish with bacterial growth

8. 1) Shape Bacilli: rod-like Spirilla: spiral-like Cocci: sphere-like
Diplo—pair
Strepto—chain
Staphlo—clump

9. Name…based on shape
Streptococcus
Staphlococcus
Diplobacillus

10. 2) Movement How do they move? Glide in ooze Flagella or cilia
Snake or spiral

11. Energy needs in bacteria
Heterotrophs: “eat” for energy
Autotrophs:
Photosynthesis Or
Chemosynthesis
What is a Photo-heterotroph?
eat for energy and photosynthesis
Autotrophic Cyanobacteria…
>3.5 BYA
Oldest know fossils!
O2 in the air

12. Cellular Energy— Photosynthesis
Autotrophic bacteria use the sun’s energy to make sugars
Glucose
LIGHT
6H2O + 6CO > C6H12O6+ 6O2
CHLOROPHYLL

13. Cellular Energy— Respiration
Heterotrophic bacteria to release energy found in organic compounds
C6H12O6+ 6O > 6H2O + 6CO2 Or
C6H12O > 6H2O + 6CO2

14. Cellular Respiration Obligate Anaerobes: lives in absence of O2
EX: botulism in canned foods
Obligate Aerobes: require O2
EX: tuberculosis, lives in the lungs

15. Cellular Respiration
Facultative Anaerobes: live w/o O2, but won’t be killed in presence
EX: E. coli, lives anaerobically in intestines and aerobically in sewage

16. Energy=Bacterial Reproduction
Two methods of bacterial reproduction
Binary fission
Conjugation
Growth is FAST…can replicate every minutes!!

17. Binary Fission Reproduction
Asexual Reproduction
Steps:
Growth
Division
Produces two identical daughter cells

18. Conjugation Reproduction
Sexual Reproduction—exchange DNA
Process:
Hollow bridge forms between bacteria
DNA is transferred from one cell to the other
Uses more energy than binary fission so….why do it???
GENETIC VARIATION

19. 3) Cell Walls Pink color Violet color
2 types of cell wall –distinguish with GRAM STAINING
Gram-negative
Pink color
Complex cell wall
Negative = bad bacteria, more resistant to antibiotics
Gram-positive
Violet color
Simple cell wall
Positive = good bacteria
Salmonella
Lactobacillus

20. Roles of Bacteria Symbiotic Relationships
Probiotic Bacteria—keep the bad bacteria in our bodies in check
E. coli—in intestines aids in digestion
Lactobacillus—small intestine
Lactobacillus

21. Roles of Bacteria Nature’s Recycling Machines Decomposers
Nitrogen fixation—from N2 (nitrogen gas) to a form plants use
Oil eating bacteria
Break down raw sewage

22. Roles of Bacteria
Many fermented foods are produced with the help of bacteria:
Cheese
Buttermilk
Yogurt
Sour cream
Vinegar
Pickles
Sourdough bread

23. Pathogen—Disease causing agent
Bacteria cause diseases in 2 ways
Damaging cells
Releasing toxins (poisons)
Acne
Propionibacterium acne

24. Homeostasis for survival
1) Balance with the environment
2) Cell membrane controls balance

25. About the cell membrane
Selectively permeable
Found surrounding all cells
Double lipid layer creates perfect barrier
RECALL : lipids are fats
lipids repel water

26. Diffusion of molecules
Concentration gradient (high to low)
No energy required- kinetic
Variables that affect rate:
-concentrations
-temperature
-size of molecule

27. 6 minute review! = equilibrium This is the goal!
6 minute review!
= equilibrium
This is the goal!

28. Osmosis = diffusion of water
Occurs naturally to maintain homeostasis
Usually causes a cell to change size
Still occurs after homeostasis is reached

29. Cell Environments
Isotonic Hypotonic Hypertonic

30. Isotonic Equilibrium Same percentage of molecules inside as outside
Molecules still move… but remain balanced

31. cell wall prevents bursting
HYPOTONIC
Less solute outside of the cell
Causes water to move in until solutes are balanced
Cell enlarges and may burst (lyse)
cell wall prevents bursting

32. Cell shape is important to proper functioning!
HYPERTONIC
More solute outside the cell
Water moves out until solute concentration is balanced
May cause cells to shrink/shrivel
Cell shape is important to proper functioning!

33. FACILATED DIFFUSION
Diffusion through channels- can be regulated unlike osmosis
EX: Sodium - Potassium pump which makes muscle cells
contract and relax properly

34. More Reviews if time!
3 minutes
4 minutes

35. THE END!