MICROBIOLOGY AND
PARASITOLOGY
(BIOL 115)
Berna Lou Aba-Regis
Instructor
MICROBIOLOGY: INTRODUCTION
• Microbiology is the study of microorganisms;
a large and diverse group of microscopic
organisms that exist as single cells or cell
clusters; it also includes viruses, which are
microscopic but not cellular
MICROBIOLOGY: INTRODUCTION
• Impact of microorganisms:
• They are responsible for cycling the chemical
elements essential for life, including carbon,
nitrogen, sulfur, hydrogen, and oxygen;
MICROBIOLOGY: INTRODUCTION
• Impact of microorganisms:
• more photosynthesis is carried out by
microorganisms than by green plants.
• There are 100 million times as many bacteria
in the oceans (13 × 10 28 ) as there are stars in
the known universe.
MICROBIOLOGY: INTRODUCTION
• Impact of microorganisms:
• It has been estimated that 5x1030 microbial
cells exist on earth; excluding cellulose, these
cells constitute about 90% of the biomass of
the entire biosphere.
• Humans also have an intimate relationship
with microorganisms; more than 90% of the
cells in our bodies are microbes.
MICROBIOLOGY: INTRODUCTION
• Impact of microorganisms:
• The bacteria present in the average human
gut weigh about 1 kg, and a human adult will
excrete his or her own weight in fecal bacteria
each year.
MICROBIOLOGY: INTRODUCTION
• Impact of microorganisms:
• Microorganisms are host to
viruses and are infected by
them
• They are found almost
everywhere in the planet
except on highly sterile sites
MICROBIOLOGY: INTRODUCTION
• They exist as normal microbiota to plants animals and
humans, as well as the opportunistic and pathogenic
groups
• Normal microbiota or microflora- harmless and mostly
beneficial to the host
• Opportunistic microbiota- Can cause disease when
condition for infection is favourable
• Pathogenic microbiota- Disease causing
MICROBIOLOGY: INTRODUCTION
• Impact of microorganisms:
• Microbes are used for understanding cellular
functions and many other cell and molecular
biology researches; including biochemistry and
biophysics
MICROBIOLOGY: INTRODUCTION
• Impact of microorganisms:
• They are being explored for
many medical applications
and pharmaceutical
potentials
MICROBIOLOGY: INTRODUCTION
• Impact of microorganisms:
• They are also used widely in the food and
beverage industry and other material industry
applications and agriculture, bioremediation,
cosmetics, artistry, etc.
• Microbes are small with tremendous impact
to our planet and our existence as a whole
Fields of Microbiology
Microbiology
Basic Microbiology
Bacteriology
Phycology
Mycology
Protozoology
Parasitology
Virology
By process
Microbial
In relation
metabolism
Immunology
Microbial
genetics
Epidemiology
Microbial
ecology
Disease-related Environment
to disease
Etiology
Infection
Control
Chemotherapy
Environmental
morphology
Microbial Taxonomy
By kind of organism
Applied Microbiology
Industry
Food and
beverage
technology
Pharmaceutical
microbiology
Genetic
engineering
Organisms included in the study of Microbiology
1. Bacteria- Bacteriology
2. Protozoans- Protozoology
3. Algae- Phycology
4. Parasites- Parasitology
5. Yeasts and Molds, Fungi - Mycology
6. Viruses- Virology
Bacteria and Parasites are Prokaryotes
PROKARYOTES
Other distinguishing characteristics of the prokaryotes
are:
• Small size, usually on the order of 1 μm in diameter,
• The DNA of almost all bacteria is a circle with a length
of about 1 mm; the prokaryotic chromosome.
• The chromosomal DNA must be folded more than
1000-fold just to fit within the prokaryotic cell
membrane.
• The small size of the
prokaryotic chromosome
limits the amount of
genetic information it can
contain.
• Any one prokaryote
carries relatively few
genes that allow
physiologic
accommodation of the
organism to its
environment.
• The range of potential prokaryotic
environments is unimaginably broad.
• The range of prokaryotic niches is illustrated
by consideration of strategies used for
generation of metabolic energy.