1. Microbiology lec-1-
Dr. Raz Nawzad

2. Microbiology
Microbiology is the study of organisms that are too small to be observed with the naked eye. 
Microbiology is a branch of biology dealing with microscopic forms of life (eg, all viruses and bacteria) and that others have macroscopic forms (eg, fungal molds and parasitic worms).

3. Aims of study:
As a science, microbiology helps to improve human lives by place their focus on the:
detection, identification, and isolation of microorganisms -- such as bacteria and fungi -- that can cause disease.
Diagnosis of diseases such as meningitis and tuberculosis, and
Prevention the spread of diseases by identifying and treating disease in the human body. 
Antibiotics were discovered through microbiology, as were vaccines and other therapeutics.

4. Microbiology
The first golden age of microbiology at (1875–1910), dates back to the pioneering studies of Pasteur and Koch, who isolated specific agents and proved that they could cause disease by introducing the experimental method.
In the first half of the 20th century, scientists studied the structure, physiology, and genetics of microbes in detail and began to answer questions relating to the links between specific microbial properties and disease.

5. Microbiology
By the end of the 20th century, the sciences of molecular biology, genetics, genomics, and proteomics extended these insights to the molecular level.
The discoveries of penicillin by Fleming in 1929 and of sulfonamides by Domagk in 1935 opened the way to great developments in chemotherapy. These gradually extended from bacterial diseases to fungal, parasitic, and finally viral infections.

6. Micro-organism
Is a microscopic living organism, which may be single-celled or multicellular.
Microorganisms play a vital role in supporting and maintaining nature and life.

7. Micro-organism The vast majority are beneficial:
They keep nature clean by removing toxins from water and soil.
allowing plant productivity.
50% of the total oxygen produced over the history of the Earth is from bacteria and 75% of additions of nitrogen to the atmosphere. 
Degrade organic matter from dead plants and animals.
In the human body they aid in digestion and help prevent invasion by harmful bacteria.

8. Micro-organisms
The major classes of microorganisms in terms of ascending size and complexity are:
viruses
bacteria
Fungi, and
parasites.

10. Viruses
Viruses are simple forms of replicating, biologically active particles that carry genetic information in either DNA or RNA molecules, but never in both.
viruses replicate only inside the living cells of other organisms (intracellular parasites of other living cells).

11. Bacteria Bacteria are the smallest (1 to 10 μm) living cells.
Their cytoplasm contains only ribosomes and a single, double-stranded DNA chromosome. Bacteria have no nucleus, but all the chemical elements of nucleic acid and protein synthesis are present.
no mitochondria, lysosomes, endoplasmic reticulum, or other organelles.

12. Fungi Fungi exist in either yeast or mold forms.
multiply by budding or mitosis.
Most fungi are free-living and widely distributed in nature.
Generally, fungi grow more slowly than bacteria.

13. Parasite
Parasites are the most diverse of all microorganisms. They range from unicellular amoebas of 10 to 12 mm to multicellular tapeworms 1 meter long.

14. Characteristic
Viruses
bacteria
fungi
parasite
cell no
yes
Type of nucleus
none
Prokaryotic
Eukaryotic
Nucleic acid
Either DNA or RNA
Both DNA and RNA
Mitochondria
Absent
Present
Method of replication
Not binary fission or mitosis
Binary fission
Budding or mitosis
Mitosis3

15. Eukaryotes & Prokaryotes
Eukaryotic and prokaryotic, which can be distinguished on the basis of their structure and the complexity of their organization.
Bacterial cells have a prokaryotic nucleus, whereas human, fungal, protozoan, and helminth cells have a eukaryotic nucleus.
Viruses are not cells and do not have a nucleus.

16. Eukaryotes
The eukaryotic cell has a true nucleus with multiple chromosomes surrounded by a nuclear membrane and uses a mitotic .
Eukaryotic cells contain organelles, such as mitochondria and lysosomes, and larger (80S) ribosomes.
Eukaryotes, do not contain peptidoglycan.

17. Prokaryotes
The nucleoid of a prokaryotic cell consists of a single circular molecule of loosely organized DNA, lacking a nuclear membrane and mitotic apparatus.
Prokaryotes contain no organelles and smaller (70S) ribosomes.
Most prokaryotes have a rigid external cell wall that contains peptidoglycan

18. Terminology
Bacteria, fungi, protozoa, and helminths are named according to the binomial Linnean system that uses genus and species, but viruses are not so named.
For example, regarding the name of Escherichia coli, Escherichia is the genus and coli is the species name.
Similarly, the name of the yeast Candida albicans consists of Candida as the genus and albicans as the species.
But viruses typically have a single name such as poliovirus, measles virus, or rabies virus. Some viruses have names with two words such as herpes simplex virus, but those do not represent genus and species.

19. Refrences:
Warren Levinson. Review of Medical Microbiology & Immunology, Tenth Edition.
Kenneth J. Ryan & C. George Ray. Sherris Medical Microbiology, Fifth Edition.