This document summarizes different types of microorganisms and their growth mechanisms. It describes bacteria, archaea, algae, fungi, protozoa, viruses, prions and lichens. It notes that bacteria are prokaryotic cells that can be classified by shape and cell wall composition. Archaea differ from bacteria in their cell structure and environments. The document outlines characteristics of algae, fungi and protozoa. It explains that viruses are obligate parasites that cause many diseases. Prions cause neurological diseases by converting normal proteins. Lichens are symbiotic organisms of fungi and microbes. The three mechanisms of microbial growth are binary fission, cell division and budding.

1. TYPES OF MICRO-
ORGANISMS AND THEIR
GROWTH
BY:
DR/ MOTAZ KABASHOR KUKU

2. INTRODUCTION
• There are several types of microbes, which include (bacteria,
archaea, algae, fungi, protozoa, viruses, prions and lichen ).
Most of these organisms can survive out side of a host (air, or
soil) with the exception of viruses which can only survive for a
brief time out side their host cell.

4. BACTERIA
• Are a prokaryotes (singled cell organisms with out a membrane
bounded nucleus). They are a much simpler cell structure than
other biological organisms.

6. BACTERIA
• The bacteria have single loop DNA, and some bacteria have an
extra genetic circle known as the Plasmid. The Plasmid contains
genes that gives an advantages such as antibiotic resistance.
• Bacteria can be classified into five types depending on their
shape:
1. Bacilli (rod).
2. Cocci (spherical).

7. BACTERIA
3. Vibrio's (comma).
4. Spirals.
5. Spirochetes (screw).
• Depending on chemical and structural composition of the cell
wall bacteria can be classified on:
1. Gram positive(taking on the stain’s purple color).

8. BACTERIA
2. Gram negative.
• Bacteria can be found in every habitat on earth, soil, oceans
and snow.
• Bacteria also live inside the body as microflora.

9. ARCHAEA
• Are single organisms. The organisms are evolutionary distinct
from bacteria, they differ from bacteria in that:
Bacteria Archaea
Cell membrane Lipid bilayer Lipid monolayer
Genes Single loop DNA tRNA , rRNA
Environment Lives everywhere Lives in low oxygen
and salt deposits
environment(water,
soil and deep sea)

10. ALGAE
• Are eukaryotes microbes (are similar to plant and animal cells
in that DNA is enclosed within nuclear membrane). The
eukaryotes contains (algae, protozoa and fungi).
• Algae have a chlorophyll and rigid cell wall.
• Algae occurs in moist environments and it may be unicellular
(spindle, rod or spherical) or can be multicellular and large.

12. FUNGI
• Some of eukaryotes organisms known as fungi, some may be
microscopic in size while others forms much larger structures
such as mushroom. these organisms can be either unicellular
or multicellular & can be range from micro to macroscopic in
size.
• Fungi do not contain chlorophyll and must absorb nutrients
from surrounding environment.

13. FUNGI
• Some fungi are pathogenic, whereas others are beneficial and
can be used for medical or fermentation purposes.

14. PROTOZOA
• Are single cell eukaryotic organisms, protozoa cell contains the
typical internal structure of animal.
• Protozoa can reside in a wide range of habitats such as soil,
marine environment and fresh water.
• Very few protozoa cause diseases, but some known to be
parasitic in nature such as plasmodium which cause malaria.

15. VIRUSES

16. VIRUSES
• Are one of the main pathogenic agents that have been
responsible for an enormous number of different diseases. All
viruses are obligate parasites (they lack metabolic machine to
generate energy or synthesis of protein, so they depends on
host cell to carry out these vital functions).
• When not residing within the host viruses exists as virions.

18. VIRUSES
• Virions have a simple structure that consists of genetic material
and a protein coat.
• Viruses are responsible for a wide range of diseases including
(common cold, measles).

19. PRIONS

20. PRIONS
• Are the simplest infectious agent, like viruses they are obligate
parasite but possess no genetic material, it just a self
perpetuating proteins. They have been implicated as the cause
of various diseases including (bovin spongiform
encephalopathy) and are suspected of playing a role in number
of other diseases.

21. LICHEN
• Are a symbiotic organisms, consists of a microbe associated
with fungus.
• The bacteria of lichen provides nutrients for the fungus,
whereas the fungus provides protective cover for the micro-
organism.

23. MECHANISMS OF MICROBIAL GROWTH
• Microbial growth refers to an increase in number of cells rather
than an increase in cell size. There are three ways of growth:
1. Replication(binary fission): most common type in which
single cell divided into two identical cell.
• The parent cell, makes copy of it’s DNA and generate enough
material to build the membrane, wall and molecular machines
for two cells. The parent cell slightly increase in size to
accommodate these additional material. Then ,

24. MICROBIAL GROWTH
The parent cell begins to contract at middle and a new piece of
cell wall is assembled at a site of contraction. This process
continuous until the parent cell is split into two cell with a
complete cell wall. The resulted cells are called daughter cells.

25. MICROBIAL GROWTH
2. Cell division: the key mechanism remain the same, but here
one cell produces two new cells in a continues cycle. Every cycle
double the number of cells in population.

26. MICROBIAL GROWTH
3. Budding: During the budding the parent cell develops a small
protrusion known as bud. The material necessary to support a
new cell are sent into the bud, which eventually split from the
parent cell to form a new daughter cell. The parent cell continues
to make a buds, but the budded daughter cell do not divide.