Microbiology Notes: Bacteria, Viruses, Fungi.

Microbiology Notes: Bacteria, Viruses & Fungi

Introduction to Microbiology:

Microbiology is the study of microscopic organisms such as bacteria, viruses, fungi, and
parasites. These microorganisms play important roles in health, disease, food production, and
the environment.

Microorganisms can be:

•Beneficial

•Harmful

•Neutral




1. Bacteria

Definition:

Bacteria are single-celled prokaryotic microorganisms that lack a true nucleus.

Characteristics of Bacteria:

•Microscopic and unicellular

•Reproduce by binary fission

•Have a cell wall

•Can live in many environments

•Some are beneficial while others cause disease


Shapes of Bacteria

Shape​ Description Example

Cocci​ Spherical​ Streptococcus
Bacilli​ Rod-shaped​ Escherichia coli
Spirilla​ Spiral-shaped Spirillum

, Useful Bacteria:

Some bacteria are beneficial because they:

•Help digestion

•Produce vitamins

•Are used in yogurt and cheese production

•Help decompose dead organisms




Harmful Bacteria:

Certain bacteria cause diseases such as:

•Tuberculosis

•Cholera

•Typhoid

•Pneumonia




2. Viruses:

Definition:

Viruses are tiny infectious agents that can only reproduce inside living host cells.

Characteristics of Viruses

•Smaller than bacteria

•Non-living outside host cells

•Contain DNA or RNA