Microbiology in the Biological World
Why study Microbiology?
1. Helps us to understand
life forms by understanding
ones.
2.
of infectious diseases
(Small pox, Typhoid fever,
Cholera).
3. Various
.
Evolution of Microbiology
1.
was
the first to observe the
microscopic world with
a 3X microscope
(1632-1723).
2.
Observed cork &
termed the word
“
”.
-
2. Theory of Spontaneous Generation (SG). Organisms appeared out
of no where.
Ex. If meat was left out flies appeared.


A.
- disproved (SG) in higher organisms but not in
microorganisms.
B.
- supported (SG) in microorganisms.
• After sterilization (Boiling) microorganisms still arouse.

C.
- disproved (SG) by conducting an experiment using
bottle swan neck flask.

Proved that dust must carry microorganisms.

D.
heating -
- dust carries bacteria that can grow after
- heat stable form of bacteria.
3. Fermentation
- First problem as a microbiologist was to
discover why the production of alcohol from sugar beets
would occasionally produce lactic acid.

1.
2.
DISCOVERED two types of bacteria
- required
- does
for survival
require oxygen
4. Germ Theory
1834 - first time disease was linked to an microorganism.

A.
- disease in silk worm was a result in a fungus infection.

B.

C.
- credited with the first attempt to prevent post
surgical infection by using diluted phenol.

D.
- developed rules to establish a cause & effect
relationship between an microorganism & a disease.
- 1865 - similar work.
• Koch’s Postulates
1.
2.
3.
4.
Microbiology
Stepping
Stones
Divisions of Microbiology

1.
- study of microorganisms that
cause disease in humans & animals.

2.
- reaction of a host to the infection.

3.
-alcohol beverages, antibodies.


4.
- harmful or beneficial to the
production of agricultural products.
5.
Synthesis of vaccine.
- recombinant DNA. Human insulin.
Medical Microbiology Past
Triumphs


1. Small Pox Viral disease - 10
million peopled died
No cases reported since 1977
2. Bubonic Plague Bacterial
Disease - 25 million people died
100 people die/year from it
Future Challenges
Not all diseases are under control.

1.
million cases of infections /year in US (22,000 deaths)

2. Lyme disease,

3. New diseases may emerge (

4. Old diseases are on the increase in US
’, AIDS, Hantavirus.
).
A. Travelers from foreign countries - 1 in 5 vistor’s come
from a country with Malaria, Yellow fever, & Cholera.
B. Resistant microbes.
C. Medicines are increasing the life span, therefore
immune system weakens in elderly people.
D. Children in developing countries were under controlled
(mumps, whooping cough, measles). Parents lax about
vaccinating children.
Cell Theory
1. Cell is the fundamental unit of life & cells come
from pre-existing cells (1839 - Schleiden &
Schwann).
Similarity in Function & Composition of Cells
All cells have the same problems:
1. Reproduce
copies of itself.
2. Obtain & use
for reproduction.
Solutions
1.
reactions.
2.
3.
4.
5.
6.
- protein molecules to speed up chemical
-
genetic information.
protein synthesis.
energy.
help enzymes.
building blocks of proteins.
Origin of Life




First form of life appeared about
Earth’s environment
High temperature,
,
catalyzed to formed amino acids (AA).
.
& lighting
Proven by
Conducted experiments where he replicated early Earth’s
environment & by inducing a spark
’s were formed.

Eventually over time
•


=>
=>
=>
Other organic compounds were mixed in until a being
developed capable of directing synthesis of simple organic
molecules.
In time self replication -
.
Prokaryotic
First cells were Prokaryotes, then over time developed into Eukaryotes.
Prokaryotes
1.
No intracellular
2.
.
present with
.
3.
•
.
DNA not separated
from the rest of
the cell
Eukaryotes
1. Intracellular membranes
present (organelles).
2. Cell membrane
present with cell
always
.
3.
.
DNA was separated from the rest
of the cell.
4. DNA -
4. DNA -proteins –
5. DNA
continuous thread.
chromosomes.
5. DNA separated into
of chromosomes
dependent on the species.
6. Reproduce Binary fission.
6. Reproduction

.
&
Prokaryotic vs Eukaryotic
Prokaryotes
Eukaryotes
Prokaryotes can be divided into two major groups.
1.
(true bacteria)
2.
- grow in hostile environments, but little
micorbiolgical importance.
Microbial world





study of all prokaryotes & unicellular eukaryotes.
Kingdom Monerans and Archaebacteria
- Algae & Protozoans
• Reproduction sexual & asexual
- smaller than protozoans & are the major cause of
diseases.
• Cyanobacteria - photosynthesis
- large multicellular eukaryote worms (flat & round).
Domains

- filamentous & unicellular eukaryotic cells.
Some cause diseases.

- 1 cell fungus, budding spores, breads & alcoholic
beverages, few produce human diseases.

- Multicellular, asexual & sexual spores, flavor fine
cheeses, few produce human diseases.

Infectious Agents



- Smallest known disease agent.
•
DNA or RNA surrounded by a protein coat.
Bacteriophages - infect bacteria.
coat.
- small piece of RNA that does not have a protein
- Proteins without DNA or RNA.
Microbial world
Microbial world
Microbial world
Cell Size