introduction of microbiology short slides

1. introduction to
microbiology
Prepared by :Safa Omar Elate
Hend mansor issa

2. Why Study Microbiology?
1. Impact on Human Health
2. Balance of Nature
3. Environmental
4. Industrial
5. Agricultural

3. Microbiology defined
 Microbiology defined - The study of microbiology is the study of
microorganisms, which are organisms that are invisible to the
naked eye except in large groups .
 Microorganisms:
 Normal flora
 Pathogenic

4. Brief History of Microbiology
Pioneers of Microbiology
Leeuwenhoek (lived 1632-1723).
First person to use microscopes to observe microbes; as a hobby he
made small handheld microscopes; he called microorganisms
“animalcules.”
Robert Hooke, UK (1665)
He first described “cellulae” (small rooms) in cork in 1665. His
discovery led to the formulation of the cell theory, which states that cells
are the basic organizational unit of all living things.

5.  Living organisms arise from nonliving things (ex. maggots come
from rotting meat).
 In the late 1600’s Francisco Redi showed that maggots developed only
in meat that flies could reach to lay eggs on.
 Many insisted that he only disproved spontaneous generation for
Macroorganisms ; maybe microbes were an exception.
 Spontaneous generation
Some forms of life could arise spontaneously from non-living matter.
Francisco Redi (1668):
Brief History of Microbiology
Pioneers of Microbiology

6. Louis Pasteur (1822-1895), Chemist:
 Fermentation (1857).
 Pasteurization: heat liquid enough to kill spoilage bacteria (1864).
 Vaccine development – rabies.
 Proposed the germ theory of disease.
 Proposed aseptic techniques (prevent contamination by unwanted
microbes).
 Director of Pasteur Institute, Paris (1894).
Brief History of Microbiology
Pioneers of Microbiology

7. Classification and Naming of Microorganisms
 Classification by structure
 Subcellular – DNA or RNA surrounded by a
protein coat – viruses
 Prokaryotic – simple cell structure with no nucleus
or organelles – bacteria
 Eukaryotic – complex cell structure with nucleus
and specialized organelles – protozoans, fungi,
parasites

8.  Standardized naming
o Genus
 Category of biologic classification
 Example – Staphylococcus
o Species of organism
 Represents a distinct type of
microorganisms
 Examples – Staphylococcus aureus and
Staphylococcus epidermidis
Classification and Naming of Microorganisms

9. All cells have:
1. Cell or plasma membrane (separates the cell from the outer
environment)
2. Genetic material (DNA)
3. Cytoplasm.
Characteristics of Prokaryotic & Eukaryotic Cells
However, within this general description we find many different types of cell.
The most important divide is between Prokaryotic (Pro – before, karyote –
nucleus) and Eukaryotic cells.

10. Prokaryotic cells are :
o comparatively simple, and small.
o The DNA is found in circles or loops and it floats in cytoplasm.
o Ribosomes (70S in size) are also found in the cytoplasm.
o While some cells have internal membranes, most have only a porous outer
membrane with a semi permeable inner membrane.
Prokaryotic cells

11. Eukaryotic cells are
structurally complex and they are generally larger than bacterial cells.
Eukaryote cells have membrane bound organelles.
Their DNA is organized into linear threads called chromosomes which
are located within a membrane, and the entire unit is called a nucleus.
Organelles that might be found in a cell include ribosomes (80S),
mitochondria, chloroplasts and golgi.
The organelles are linked by membranes. Their position and the
activity of organelles within the cell is regulated by the cytoskeleton.
The cytoskeleton has two main components, microfibrils made of actin
and microtubules made of tubulin . Animals,
Plants, Fungi ,Protista are found within the Eukaryota.
Eukaryotic cells