Microbiology is the study of microorganisms, including bacteria, fungi, algae, protozoa, and viruses. These microorganisms exist as single cells or cell clusters that must be viewed microscopically. Key characteristics of microorganisms include metabolism, differentiation, reproduction, communication, and evolution. The study of microbiology provides insights into basic science concepts like molecular biology and genetics, and has practical applications in medicine, industry, agriculture, and ecology.

1. What is microbiology
Study of Micro-organisms: Organisms that EXIST as Single
Cells or cell clusters and must be viewed individually with the
aid of a Microscope
1. EXIST (Webster definition)To continue to be, have life; live
HALLMARKS OF LIFE
1. METABOLISM (nutrient uptake, biomass, waste output)
2. DIFFERENTIATION (Bacillus spp. Caulobacter)
3. REPRODUCTION (binary fission)
4. COMMUNICATION (Pseudomonas aeruginosa)
5. EVOLUTION (antibiotic resistance, pathogens)

2. Metabolism
Take in nutrients from the environment
glucose, lactose, other sugars, fats=lipids, proteins,
toxic wastes, oils and petrol
Assimilate the nutrients into BIOMASS
DNA, proteins, carbohydrates and
complex carbohydrates, lipids
Release waste products into the environment
gases, alcohols, acids and organic compounds

3. Differentiation— to form distinct
structures
Caulobacter spp. Vegetative cells versus stalk cells
K.C. Keiler M. Dworkin

4. Differentiation— to form distinct
structures
Bacillus spp. endospore forming cells
Anabaena spp. Cyanobacteria forming heterocysts
T.J. Deveridge M. Dworkin

5. Reproduction
To generate progeny of ones same type
A bacterium duplicates its DNA and forms a daughter cell via binary fission
Yeast duplicates its DNA and forms a daughter cell via budding, or mates with
another yeast cell and produces haploid progeny.
J. Pitocchelli E. Hettema

6. Communication
interaction with
other cells—response to
other cells
Vibrio fischeri and
Lantern fish
Kolter and Losick
AMNH--NYC

7. www.med.umich.edu
Genomenewsnetwork
Communication
Biofilms and
Health

8. Evolution
To change ones genetic make up (DNA sequence) to
adapt to ones environment
Bacteria can take up DNA from the environment or other cells via
Transformation—uptake of naked DNA
Transduction—phage (bacterial specific virus) mediated
uptake of DNA
Conjugation—uptake of DNA that requires the interaction
of two bacteria
Antibiotic resistance, bacterial pathogenesis

9. What is microbiology
Study of Micro-organisms: Organisms that EXIST as Single
Cells or cell clusters and must be viewed individually with the
aid of a Microscope

10. 2. KEYWORD single CELLS
(OR cell clusters)
CHARACTERISTICS THAT MICROORGANISMS HAVE THAT
MAKE THEM TRUE CELLS
1. CELL MEMBRANE –barrier that separates the inside of the
cell from the outside
2. NUCLEUS OR NUCLEIOD – location of genetic
information (DNA)
3. CYTOPLASM –location of the machinery for cell growth and
function
4. MACROMOLECULES – proteins, nucleic acids, lipids,
polysaccharides

11. 3. KEYWORD exist as SINGLE cells
(OR cell clusters)
We are multicellular creatures—made up of many cells
What makes one of our cells different from a microbial cell??
A single microbial cell can have an independent existence—our
specialized cells need to interact with other cells in order to carry
out their cellular functions for the good of the entire organism.

12. What organisms are considered to be
microbial cells and studied in microbiology
1. BACTERIA
2. FUNGI
3. ALGAE
4. PROTOZOA
5. Viruses(although not a cellular entity but an
intracellular pathogen)
6. Prions (a biochemical anomaly—misfolded proteins)
7. Helminths Worms (multicellular)

13. Taxonomy
The study of phylogenetic relationships between organisms
(The sorting of all living things based on their related or
differentiating features)
KINDOM the highest level in classification
PHYLUM related classes
CLASS related orders
ORDER related families
FAMILY related genera
GENUS closely related species
SPECIES organisms sharing a set of biological traits and
reproducing only with their exact kind
Further classifications especially with bacteria:
Strain—organisms within a species varying in a given quality
Type—organisms within a species varying immunologically

14. Taxonomy::relatively easy to classify animals and plants
based on their behaviour and appearance—old school

15. Taxonomy::initially not easy to classify microorganisms
based on their behaviour and appearance
Advancements in DNA amplification and DNA sequencing has
greatly helped
The phylogenetic relationships between microorganisms can
be determined by sequencing the 16S and 18S ribosomal RNA
of the organisms in question
(ribosomal RNA—structural RNA of the ribosome that plays
a role in protein synthesis)

16. Phylogenetic classification of micro-
organisms (new school)
Universal Ancestor
Algae
Fungi
Protozoa
Prokaryotic
Eubacteria Archaeabacteria
Eukaryotic

17. Phylogenetic classification of micro-organisms
EUBACTERIA most abundant of the bacteria
found in soil, water and animal digestive tracts
ARCHAEACTERIA live in extreme conditions
(temperature, pH etc) mostly anaerobic (unable to live in the
presence of oxygen)
EUKARYOTES algae: live in soil and water, contains
chlorophyll for photosynthesis, has a cell
wall
fungi: yeast, molds. Lack chlorophyll and
obtains energy from organic compounds in
soil and water, has a cell wall
protozoa: colorless, lacks a cell wall,
ingests other organisms or organic particles

18. Major Differences between prokaryotic and
eukaryotic micro-organisms
Prokaryotes
1. Nonmembrane bound
nucleiod region
2. DNA-one circular molecule
one chromosome
3. Haploid-One copy of a gene
4. Plasma membrane does not
contain sterols
5. Reproduction—simple binary
fission
Eukaryotes
1. Membrane bound nucleus
containing DNA
2. DNA-linear molecules arranged
to form several chromosomes
3. Diploid-Two copies of a gene
4. Plasma membrane contains
sterols
5. Reproduction—meiosis and
mitosis
6. Presence of membrane bound
organelles such as chloroplasts
and mitochondria

19. Why study Microbiology ??
Microbiology as a BASIC Science
Bacteria and yeast are useful in studying molecular biology,
biochemistry and genetics
--reproduce rapidly
--are genetically (DNA) and biochemically more simple
than higher order organisms
--working with bacteria and yeast for understanding
life processes has no ethical ramifications
Microbiology as an APPLIED Science
Medicine—Vaccine development, production of antibiotics,
production of important biological enzymes (insulin)
Industry—Production of beer, wine, cheeses and yogurt
Agriculture—maintenance of soil fertility/digestion in cattle
Ecology—Bioremediation—microorganisms that degrade
toxic waste materials