1. BACTERIA chapter 24 Characteristics no membrane bound nucleus
single chromosome
reproduce by fission
great metabolic diversity

2. Table 24.2a A comparison of the three domains of life (part 1)

3. Table 24.2b A comparison of the three domains of life (part 2)3

4. Archaebacteria
Some archaea live in extreme environments and are called extremophiles
Extreme halophiles
live in highly saline environments
Extreme thermophiles
thrive in very hot environments
Methanogens
produce methane as a waste product
strict anaerobes and are poisoned by O2
found in swamps and marshes, in the guts of cattle, and near deep-sea hydrothermal vents 4

5. Eubacteria Includes most familiar bacteria
Have fatty acids in plasma membrane
Most have cell wall; always includes peptidoglycan
network of modified sugars cross-linked by polypeptides
which maintains cell shape, protects the cell, and prevents it from bursting in a hypotonic environment
Classification based largely on metabolism

6. Photoautotrophic
Cyanobacteria
get e- and H+ from H2O and release free O2
light trapping pigments and e- transfer chains
Chemoautotrophic
Anaerobes
free oxygen kills them
get e- and H+ from gaseous H2, H2S and other inorganic compounds

7. Chemoheterotrophic
saprotrophic
must consume organic molecules for energy and carbon
known as decomposers
Photoheterotrophic
use light for energy
must obtain their carbon in organic form

8. Table 24.1 Major nutritional modes8

9. Bacterial Behavior Bacteria move toward nutrient-rich regions Taxis
the ability to move toward or away from a stimulus
Chemotaxis
the movement toward or away from a chemical stimulus
Aerobes move toward oxygen; anaerobes avoid it
Photosynthetic types move toward light
Magnetotactic bacteria swim downward

10. The Role of Oxygen in Metabolism
Prokaryotic metabolism varies with respect to O2
Obligate aerobes
require O2 for cellular respiration
Obligate anaerobes
poisoned by O2 and use fermentation or anaerobic respiration, in which substances other than O2 act as electron acceptors
Facultative anaerobes
can survive with or without O2 10

11. Nitrogen Metabolism
Nitrogen is essential for the production of amino acids and nucleic acids
Prokaryotes can metabolize nitrogen in a variety of ways
In nitrogen fixation, some prokaryotes convert atmospheric nitrogen (N2) to ammonia (NH3) 11

12. Adaptations of Prokaryotes
The ongoing success of prokaryotes is an extraordinary example of physiological and metabolic diversification
Prokaryotic diversification can be viewed as a first great wave of adaptive radiation in the evolutionary history of life 12

13. Bacteria contain the following structures
DNA (circular)
cell wall (peptidoglycan)
thin plasma membrane
flagella
cilia

14. Gram Stain
Gram stain

15. Stained bacteria
Gram negative
red
less peptidoglycan
outer membrane can be toxic
Gram positive
purple
simpler walls with a large amount of peptioglycan

16. (a) Gram-positive bacteria Peptido- Cell glycan wall layer Plasma
Figure 24.7a Gram staining (part 1: Gram-positive)
Plasma
membrane 16

17. of lipopolysaccharide
(b) Gram-negative
bacteria
Carbohydrate portion
of lipopolysaccharide
Outer
membrane
Cell
wall
Figure 24.7b Gram staining (part 2: Gram-negative)
Peptidoglycan
layer
Plasma membrane 17

18. Bacterial Shapes
Cocci
round
Bacilli
rod
Spirilla
spiral

19. Bacterial Arrangements
Staphlo
Grape like clusters
Strepto
chains
Diplo
pairs

20. Bacteria Reproduction
Prokaryotes reproduce quickly by binary fission and can divide every 1–3 hours
Key features of prokaryotic biology allow them to divide quickly
small
binary fission
short generation times 20

21. :

22. Prokaryotic Fission
Prokaryotic fission

23. Genetic Variation Prokaryotes have considerable genetic variation
Three factors contribute to this genetic diversity
Rapid reproduction
Mutation
Genetic recombination 23

24. Genetic Recombination
Genetic recombination, the combining of DNA from two sources, contributes to diversity
Prokaryotic DNA from different individuals can be brought together by
Transformation
Transduction
Conjugation
Movement of genes among individuals from different species is called horizontal gene transfer 24

25. Transformation and Transduction
prokaryotic cell can take up and incorporate foreign DNA from the surrounding environment
Transduction
movement of genes between bacteria by bacteriophages (viruses that infect bacteria) 25

26. Phage infects bacterial donor cell with A and B alleles.
Phage DNA 1
Phage infects bacterial
donor cell with A and
B alleles.
A B
Donor cell
Figure Transduction (step 1) 26

27. Phage infects bacterial donor cell with A and B alleles.
Phage DNA 1
Phage infects bacterial
donor cell with A and
B alleles.
A B
Donor cell 2
Phage DNA is
replicated and
proteins synthesized. A B
Figure Transduction (step 2) 27

28. Phage infects bacterial donor cell with A and B alleles.
Phage DNA 1
Phage infects bacterial
donor cell with A and
B alleles.
A B
Donor cell 2
Phage DNA is
replicated and
proteins synthesized. A B 3
Fragment of DNA with
A allele is packaged
within a phage capsid. A
Figure Transduction (step 3) 28

29. Phage infects bacterial donor cell with A and B alleles.
Phage DNA 1
Phage infects bacterial
donor cell with A and
B alleles.
A B
Donor cell 2
Phage DNA is
replicated and
proteins synthesized. A B 3
Fragment of DNA with
A allele is packaged
within a phage capsid. A
Crossing over
Figure Transduction (step 4) 4
Phage with A allele
infects bacterial
recipient cell. A
A− B−
Recipient
cell 29

30. Phage infects bacterial donor cell with A and B alleles.
Phage DNA 1
Phage infects bacterial
donor cell with A and
B alleles.
A B
Donor cell 2
Phage DNA is
replicated and
proteins synthesized. A B 3
Fragment of DNA with
A allele is packaged
within a phage capsid. A
Crossing over
Figure Transduction (step 5) 4
Phage with A allele
infects bacterial
recipient cell. A
A− B−
Recipient
cell
Recombinant
cell 5
Incorporation of phage
DNA creates recombinant
cell with genotype AB.
A B− 30

31. Conjugation and Plasmids
Conjugation is the process where genetic material is transferred between prokaryotic cells
In bacteria, the DNA transfer is one way
In E. coli, the donor cell attaches to a recipient by a pilus, pulls it closer, and transfers DNA 31

32. 1 m
Sex pilus
Figure Bacterial conjugation 32

33. The F factor is a piece of DNA required for the production of pili
Cells containing the F plasmid (F+) function as DNA donors during conjugation
Cells without the F factor (F–) function as DNA recipients during conjugation
The F factor is transferable during conjugation 33

34. F cell (donor) F− cell (recipient)
Bacterial
chromosome
F plasmid
F cell
(donor)
Mating
bridge
F− cell
(recipient)
Bacterial
chromosome 1
One strand of
F cell plasmid
DNA breaks at
arrowhead.
Figure Conjugation and transfer of an F plasmid, resulting in recombination (step 1) 34

35. F cell (donor) F− cell (recipient)
Bacterial
chromosome
F plasmid
F cell
(donor)
Mating
bridge
F− cell
(recipient)
Bacterial
chromosome 1
One strand of
F cell plasmid
DNA breaks at
arrowhead.
Figure Conjugation and transfer of an F plasmid, resulting in recombination (step 2) 2
Broken strand
peels off and
enters F− cell. 35

36. F cell (donor) F− cell (recipient)
Bacterial
chromosome
F plasmid
F cell
(donor)
Mating
bridge
F− cell
(recipient)
Bacterial
chromosome 1
One strand of
F cell plasmid
DNA breaks at
arrowhead.
Figure Conjugation and transfer of an F plasmid, resulting in recombination (step 3) 2
Broken strand
peels off and
enters F− cell. 3
Donor and
recipient cells
synthesize
complementary
DNA strands. 36

37. F cell (donor) F cell F cell F− cell (recipient)
Bacterial
chromosome
F plasmid
F cell
(donor) F
cell
Mating
bridge F
cell
F− cell
(recipient)
Bacterial
chromosome 1
One strand of
F cell plasmid
DNA breaks at
arrowhead.
Figure Conjugation and transfer of an F plasmid, resulting in recombination (step 4) 2
Broken strand
peels off and
enters F− cell. 3
Donor and
recipient cells
synthesize
complementary
DNA strands. 4
Recipient cell
is now a
recombinant
F cell. 37

38. Spore Formation
allows bacteria to remain dormant when conditions are unfavorable to reproduce
has thick internal wall that protects DNA
dehydrated form

40. Methicillin-resistant Staphylococcus aureus

42. Bacterial diseases: What are they and what do they affect?
Gram + infections:
Streptococcus
Strep throat
Staphylococci (staph infection)

43. Diphtheria
membrane becomes inflamed over windpipe
Botulism
Food poisoning

44. Tetanus
caused by deep puncture wound
produces poisons and toxins which over stimulates the nervous system
causes muscle spasms
commonly known as lock jaw

45. Gram – infections
E. Coli
found in
your intestine
helps digest fat and produce vitamin K
improperly processed meat
Acid Fast infections
TB –(tuberculosis)
affects the lungs

46. Leprosy (Hansen's Bacillus)
attacks and destroys nerves
causes deformities, even loss of parts