Classification and importance of Micro organisms
Session 2: Classification and importance of Micro organisms
Total Session Time: 120 minutes
Pre-requisites
Students Learning Tasks
By the end of this session students are expected to be able to:
Resources Needed:
SESSION OVERVIEW
|Step |Time |Activity/ |Content |
| | |Method | |
|1 |5 minutes |Presentation |Introduction, Learning Tasks |
|2 | |Small group |Differences between eukaryotic and|
| |30 minutes |discussion/ |prokaryotic cells |
| | |Presentation | |
|3 |50 minutes |Buzzing/ |Classification and nomenclature of|
| | |Presentation |microorganisms |
|4 |25 minutes |Presentation |Importance of microorganisms in |
| | | |pharmacy |
|5 |5 minutes |Presentation |Key Points |
| 6|5 minutes |Presentation |Evaluation |
SESSION CONTENTS
STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)
READ or ASK students to read the learning tasks and clarify
ASK students if they have any questions before continuing
STEP 2: Differences between eukaryotic and prokaryotic cells (30 minutes)
|Activity: Small Group Discussion (10 minutes) |
| |
|DIVIDE students into small manageable groups |
| |
|ASK students to discuss on the following question |
|What are the differences between eukaryotic and prokaryotic cells? |
| |
|ALLOW students to discuss for 10 minutes |
| |
|ALLOW few groups to present and the rest to add points not mentioned|
| |
| |
|CLARIFY and SUMMARIZE by using the contents below |
All living things are made up of cells and cells are the smallest
units of any living organism. All cells are grouped into two major
groups, eukaryotic and prokaryotic cells.
The differences between eukaryotic cells and prokaryotic cells are
summarized as follow:
|Eukaryotic Cells |Prokaryotic Cells |
|Larger than eukaryotic cells |Small than eukaryotic cells |
|(>10um) |(<5um) |
| have no rigid cell wall | have rigid cellwall |
|Always have nucleus and other |No nucleus or any other |
|membrane-bound organelles |membrane-bound organelles |
|DNA is linear |DNA is circular, |
|Ribosomes are larger (80S) |Ribosomes are small (70S) |
|Have cytoskeleton |No cytoskeleton |
|Move by cilia or flagella |Move by flagella |
|Cell division is by mitosis or |Cell division is by binary |
|meiosis |fission |
|Reproduction is asexual or sexual |Reproduction is always asexual |
Figure 2.1: Prokaryotic Cell
[pic]
Figure 2.2: Eukaryotic Cell
[pic]
STEP 3: Classification and nomenclature of microorganisms (50 minutes)
|Activity: Buzzing (5 minutes) |
| |
|ASK students to pair up and buzz on the following question for 2 |
|minutes |
| |
|What is classification of microorganisms? |
| |
|ALLOW few pairs to respond and let other pairs to add on points not |
|mentioned |
| |
|WRITE their response on the flip chart/board |
| |
|CLARIFY and SUMMARIZE by using the content below |
unicellular, multicellular, or cell clusters
some can cause serious harm
to facilitate research and communication
properties (similarities) using a set of rules and an estimate as to how
closely related it is to a common ancestor (evolutionary relationship)
in a way to create an order
classified is called a domain
o The domain has three subgroups: bacteria, archae, and eukarya
o This first group defines whether an organism is a prokaryote or a
eukaryote
o There are five major kingdoms and include prokaryota (e.g. archae
and bacteria), protoctista (e.g. protozoa and algae), fungi,
plantae, and animalia
o A kingdom is further split into phylum or division, class, order,
family, genus, and species, which is the smallest group
o G + C base composition
o DNA analysis using genetic probes
o Nucleic acid sequencing and rRNA analysis
archaea, fungi, protozoa, algae, and viruses
o Bacteria are unicellular organisms described as prokaryotic because
they lack a nucleus
o They exist in four major shapes: bacillus (rod shape), coccus
(spherical shape), spirilla (spiral shape), and vibrio (curved
shape)
o Most bacteria have a peptidoglycan cell wall; they divide by binary
fission; and they may possess flagella for motility
o The difference in their cell wall structure is a major feature used
in classifying them
o According to the way their cell walls structure stains, bacteria
can be classified using the Gram-staining as either
o Bacteria can be further divided based on their response to gaseous
oxygen into the following groups:
o According to the way they obtain energy, bacteria are classified as
heterotrophs or autotrophs
sunlight or chemical reactions, in which case they are called
chemoautotrophs
organisms. Bacteria that use decaying life forms as a source of
energy are called saprophytes.
o Viruses are noncellular entities that consist of a nucleic acid
core (DNA or RNA) surrounded by a protein coat
o Although viruses are classified as microorganisms, they are not
considered living organisms
o Viruses cannot reproduce outside a host cell and cannot metabolize
on their own. Viruses often infest prokaryotic and eukaryotic cells
causing diseases
o Fungi (mushroom, moulds, and yeasts) are eukaryotic cells (with a
true nucleus). Most fungi are multicellular and their cell wall is
composed of chitin
o They obtain nutrients by absorbing organic material from their
environment (decomposers), through symbiotic relationships with
plants (symbionts), or harmful relationships with a host
(parasites)
o They form characteristic filamentous tubes called hyphae that help
absorb material
o The collection of hyphae is called mycelium
o Fungi reproduce by releasing spores
o Protozoa are unicellular aerobic eukaryotes
o They have a nucleus, complex organelles, and obtain nourishment by
absorption or ingestion through specialized structures
o They make up the largest group of organisms in the world in terms
of numbers, biomass, and diversity
o Their cell walls are made up of cellulose
o Protozoa have been traditionally divided based on their mode of
locomotion: flagellates produce their own food and use their whip-
like structure to propel forward, ciliates have tiny hair that beat
to produce movement, amoeboids have false feet or pseudopodia used
for feeding and locomotion
o Algae, also called cyanobacteria or blue-green algae, are
unicellular or multicellular eukaryotes that obtain nourishment by
photosynthesis
o They live in water, damp soil, and rocks and produce oxygen and
carbohydrates used by other organisms
o It is believed that cyanobacteria are the origins of green land
plants
o Uses binomial (scientific) nomenclature in which two names:
handwritten
STEP 4: Importance of micro organisms in Pharmacy (25 minutes)
Microorganisms are very important in pharmacy. Importance of
microorganisms in pharmacy includes;
important to prevent, treat and prevent infections
biological indicators such as spores of Bacillus stearothermophilus
substances useful in pharmacy and medicine
o Production of antibiotics such as Penicillin
o Production of hormonal products such as Insulin
o Production of vaccines such as Tuberculosis vaccine
STEP 5: Key Points (5 minutes)
by the naked eye
viruses and multicellular animal parasites
medicines such as antibiotics
STEP 6: Evaluation (5 minutes)
References
Hugo and Russell (2011), Pharmaceutical Microbiology 8th Edition, Willey-
Blackwel publications
Karen C. Carroll et al (2013); Jawetz, Melnick and Adelberg’s Medical
Microbiology 26th Ed. McGraw Hill Co. Inc.
Greenwood et al (2012); Medical Microbiology, 18th edition Churchill
Livingstone
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