1. The Monera
Introduction:
The Kingdom of monera include all prokaryotic
organisms
Prokaryotic organisms have their genetic
materials that are not surrounded by nuclear
envelope
Their genetic material is DNA appeared as more
dense component in their cytoplasm
All bacterial species and Cyanobacteria are
included in this Kingdom (monera)

2. Prokaryotic organisms
All prokaryotes are unicellular organisms
These prokaryotes include:
– Primitive Archeabacteria and photosynthetic
cyanobacteria (a small group)
– True bacteria (all bacterial species excluding the
above) (Most of bacterial species belong to this
group)

3. Size, shape, and arrangement
Size
–
–
–
–
–
Varies depends on species
Ranging between 0.5 – 2.0 micron (Generally)
Some may exceed those range (spirally bacteria)
Group of cyanobacteria may reach 60 micron
This size make them to have very high ratio of
surface area : cell volume
Shape
– There are 3 main shapes of bacterial species (Rod,
spherical, and spiral)
– These main shape often produce morphological
variation

4. Arrangement of the cell
– Some are found to have distinctive morphology
– This happen for the bacterial cells that undergo cell
division that is not followed by separation between
them
– Cell division may occur in one plane or more
– This type or mode of reproduction usually occur in the
spherical bacterial species
– Some arrangement occur as a result:
Diplococci
Sarcina
Streptococci
Staphylococci
– Rarely happen in other bacterial morphology

5. Various morphology of bacterial species

6. The structure of prokaryotes
Mainly consists of the following components:
– Plasma membrane
Surrounding the cytoplasm
This membrane is surrounded by cell wall
Some species have outer membrane
– Internal cytoplasm
We can find organelles, such as ribosomes, nucleoid,
granules, and vesicles
– External structure
May vary and depends on species
Can be in the form of capsules, flagella, and pilli.

8. The cell wall
This is a semi rigid part that is located outside of
the plasma membrane
The main functions are:
– To maintain the characteristic shape of the cell
– To protect the cells from lyses when exposed to
hypotonic solutions
This cell wall can be degraded by lysozymes
It has pores, but does not play any role to
transport materials in or out of the cell

9. The components of cell wall
Peptidoglycan is the main component of
the bacterial cell wall
The main components of the
peptidoglycan:
– N-Acetyl glucosamine
– N-muramic acid
– Theicoic acids
– These are covalently bound

10. Outer membrane
Normally found in Gram negative bacteria
This is a bilayer structure (similar to plasma
membrane)
The function: to control transport of substance in
and out of the cell (not very significant)
The outer surface of this structure has antigen
and receptors (some specific to viral protein)
Bacterial endotoxins are located in this outer
membrane

11. Other external structures
Flagella
– This structure enables some species to actively move
(motile)
– One species may have one, two, or more flagella
– Based on the location on the cell, bacterial cells can
be grouped into:
Monottrichous (one flagellum on one pole)
Amphitrichous (one flagellum on each pole)
Lophotrichous (more than 2 flagella on one pole)
Peritrichous (Flagella on all surface of the cell)
Pilli
– Flagella-like structure
– Two types of pilli (attachment and conjugation pilli)

12. Arrangement of flagella on the bacterial cells
a.
b.
c.
d.
Monotrichous
Amphitrichous
Lophotrichous
Peritrichous

13. Capsule
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–
–
–
–
–
Located outside of the cell wall
It consists of complex molecule of polysaccharide
It protect the internal part of the cell from desication
Only certain bacterial species posses this structure
Capsule will improve pathogenity of a species
Example Bacillus anthraxis (produce this structure
when it infects its host)
– When a bacterial cell lose this structure it will lose its
ability to infect its host.
Slime layer

14. Internal structures
Plasmid
– Circular extra chromosomal (self replication)
– It has genes encoding Antibiotic resistance
Ribosome
– The site of protein synthesis
– They are composed of protein and RNA
Endospores
– They are formed under stressful conditions
Nucleoid (Nuclear region)

15. Reproduction modes
Asexual
– Common mode
– Binary fission
Sexual
– Conjugation

16. Recombination
Variation occur as new foreign DNA enter
the bacterial cells
This can happen in three ways:
– Transformation
Free foreign DNA enters the bacterial cell
– Transduction
Foreign DNA enters the bacterial cells mediated by
viruses as vectors
– Conjugation
Transfer of genetic materials through pilli
conjugation

17. Grouping bacterial species based
on modes of obtaining food
Autotrophic bacteria
– Photoautotroph
Pigmented bacteria
– Chemoautotroph
Examples: Nitrosomonas sp. (convert ammonia to HNO2,
Nitrobacter, Nitrosococcus
Heterotrophic bacteria
– Most bacteria belong to this group

18. Based on the O2 requirement
Aerobic
– Need O2 in their metabolism
– Example: Nitrosomonas
Anaerobic
– Does not need O2
– O2 can be toxic for them
– Examples; Clostridium botulinum, C. tetani,
Lactic Acid Bacteria (facultative)

19. Role of bacteria
Advantage
Disadvantage
Study the worksheet for this!!!!