This document provides an overview of different types of microbes (microorganisms) that can only be seen with a microscope. It discusses three main types: viruses, bacteria, and fungi. Viruses are the smallest and use host cells to reproduce. Bacteria come in various shapes and sizes and can cause illnesses. Fungi include unicellular yeast and multicellular mushrooms; yeast reproduces through budding from parent cells. The lesson aims to distinguish between these microbe types and describe their important characteristics and examples of diseases they cause.

1. CLASS: Integrated Science Form 4
TOPIC OF LESSON: Types of Microbes
MODULE / SECTION: Cells & Unicellular Organism

2. OBJECTIVES
SYLLABUS OBJECTIVE(S) [OBJETIVO DE SYLLABUS]
Candidate should be able to:
● Discuss the importance of selected microbes;
El candidato debe ser capaz de:
● Discuta la importancia de los microbios seleccionados;

3. OBJECTIVES
LESSON OBJECTIVE(S) [OBJETIVOS DE LA LECCIÓN]
By the end of this lesson, the student should be able to:
● Distinguish between the different types of microbes - viruses, bacteria, and fungi;
● Describe important characteristics of each type of microbe;
● List examples of diseases caused by each type of microbe.
Al final de esta lección, el estudiante debe poder:
● Distinguir entre los diferentes tipos de microbios: virus, bacterias y hongos;
● Describa las características importantes de cada tipo de microbio;
● Lista de ejemplos de enfermedades causadas por cada tipo de microbio.

4. GLOSSARY [will fit better in platform]
ENGLISH SPANISH
attach adjuntar
be of benefit ser de beneficio
burst ráfaga
can lead to puede llevar a
copies of Copias de
crops cultivos
disease enfermedad
enclosed adjunto
even incluso
eventually finalmente
float freely flotar libremente
focusing on enfocado en
food spoilage deterioro de los alimentos
fungus hongo
host anfitrión

5. KeyWords
Look out for the Key Words. They are new words that will be in the
Glossary above.
They will be highlighted like this:
Key Word

6. INTRODUCTION
In this lesson we will be looking at
microorganisms.
The gif is that of BACTERIA,
which is one type of
microorganism (aka microbe).
This lesson will look at this and
two other types of microbes.
What do you think those other
types are?
Do you think they will look the
same?

7. EXPLANATION
Microorganisms, aka
microbes, are unicellular
organisms which are only
visible with the aid of a
microscope.

8. EXPLANATION
There are three types of
microbes:
● Viruses
● Bacteria
● Fungi
Viruses are the smallest,
fungi are the largest.
They have various shapes
and sizes.

9. VIRUSES
All are pathogens.
However, not all hosts are
humans. Therefore not all
viruses are harmful to
humans.
Some can even be of benefit.
Pathogenic viruses cause
diseases such as influenza,
cold sores, chicken pox,
mumps, measles and AIDS. HEPATITIS C VIRUS
(Centre for Disease Control)

10. VIRAL STRUCTURE
All consist of genetic material
(DNA or RNA) enclosed in a
protective protein coat.
Size range:
20 to 400 nm (nanometres)
[1 million nm in 1 mm).
HEPATITIS C VIRUS
(Centre for Disease Control)

11. HOW DO VIRUSES REPRODUCE?
Viral reproduction (aka viral replication) has three (3)
main stages:
1. The virus attaches itself to the host cell and injects
its genetic material into the cell
2. The genetic material then forces the cell’s
machinery to make more copies of the virus’
material (genetic material + components of the
protein coat)
3. The host cell eventually bursts to release new
viruses into its surroundings.
Click on the triangle and watch the video for more
details…

12. BACTERIA
Some bacteria are harmful to our health,
and also cause food spoilage.
Pathogenic bacteria cause illnesses such
as:
● Food poisoning caused by salmonella
● Whooping cough
● Meningitis
● Tuberculosis (TB)
● Gonorrhoea

13. BACTERIAL STRUCTURE I
There are many types of bacteria, with a wide variety of shapes and sizes.

14. BACTERIAL STRUCTURE II
Bacteria are larger than viruses but smaller than fung, as well as animal & plant cells.
Width ranges from 0.1 to 50 µm (micrometres) [1,000 µm in 1.0 mm]

15. BACTERIAL STRUCTURE III
All bacteria have a typical cell structure,
with some differences.
The most important difference is that the
genetic material is not contained in a
nucleus. Instead, it floats freely in the
cytoplasm.
Another difference is that, like a plant cell,
it has cell wall. But it also has an additional
cell capsule with a slimy consistency.

16. FUNGI
There is a wide variety in the types of fungi that exist.
Some, like yeast, is unicellular. This lesson will focus on
yeast.
Others, like mushrooms, are multicellular and can be seen
with the naked eye.
Overgrowth can harm the host organism / substrate on
which they grow.
For example:
● The unpleasant and unsightly growth of mould,
athlete’s foot or thrush
● In agriculture, fungal infestations can lead to loss of
crops and income.

17. YEAST STRUCTURE
Yeast has the typical structure of
a plant cell, minus the
photosynthesizing chloroplast.

18. YEAST REPRODUCTION
They reproduce asexually
by a process called
BUDDING.
The buds eventually break
away from the parent cell
to form a new yeast cell.

19. SUMMARY
● A microorganism is also known as a microbe.
● A microbe is an organism that can only be seen with a microscope. It is too small to be seen with
the naked eye. It is usually unicellular, which means it is made of one cell.
● This lesson looked at three main types of microbes: viruses, bacteria and fungi. Viruses are the
smallest and fungi are the largest.
● Viruses are basically made up of a protein coat protecting genetic material. All are pathogens but
not all are harmful to humans. They use their host cells to reproduce.
● Bacteria have a wide range of sizes and shapes, but typically have a structure similar to a cell, with
an extra cell wall and cell capsule protecting it.
● Most fungi are multicellular. Yeast, however, is unicellular, with a structure very similar to that of a
plant cell, minus the chloroplast.
● Yeast reproduces asexually via a process called budding.

20. Now Let’s See if You Understand...
Click on the following link. It is a quiz.
https://quizizz.com/join?gc=033290&source=liveDashboard

21. REFERENCES
Centers for Disease Control & Prevention, Illustration of the Hepatitis C Virus, viewed on 16th July 2019,
<https://www.cdc.gov/nchhstp/newsroom/images/2016/HCV-virus-highres.png>
CNX OpenStax, viewed on 16th July 2019,
<https://commons.wikimedia.org/wiki/File:OSC_Microbio_01_03_sizes.jpg>
Conn, H.W., 1917, Image from page 110 of “Bacteria, yeasts and molds in the home”, viewed on 16th July 2019,
<https://www.flickr.com/photos/internetarchivebookimages/20772715922/>
Domdomegg (Wikimedia Commons), File: Simple diagram of bacterium (en).svg, viewed on 16th July 2019,
<https://commons.wikimedia.org/wiki/File:Simple_diagram_of_bacterium_(en).svg>
DONIYER YAKHSHIBAYE / 7, viewed on 16th July 2019, <https://pxhere.com/en/photo/1583873>
Doug Jordan, M.A, USCDCP, viewed on 16th July 2019, <https://pixnio.com/science/microscopy-
images/influenza/portion-of-the-virions-outer-protein-coat-has-been-cut-away-which-reveals-the-virus-
contents>

22. REFERENCES
Mariana Ruiz, File: Bacterial morphology diagram.svg, viewed on 16th July 2019,
<https://en.wikipedia.org/wiki/Bacteria#/media/File:Bacterial_morphology_diagram.svg>
NA, (gIF: bacteria moving around), viewed on 16th July 2019,
<https://media3.giphy.com/media/8lsNyZVWcpZ2o/giphy.gif?cid=e1bb72ff5d2df504677445476b283dc4
&rid=giphy.gif>
OpenClipart-Vectors from Pixabay, (Microscope-Scientist-Image), viewed on 16th July 2019,
<https://pixabay.com/vectors/analysis-biology-cell-cell-culture-2025834/>
Public Domain, viewed on 16th July 2019, <https://pxhere.com/en/photo/171607>
Ricochet Science, 24th Nov 2014, The Viral Life Cycle, viewed on 16th July 2019,
<https://youtu.be/uIut0oVWCEg>
Tania Chung, 2017, Integrated Science for CSEC Examinations, Macmillan Education, London, viewed on 16th
July 2019
UMass Amherst Libraries, 11th May 2016, 57. Budding of Yeast Cells, viewed on 16th July 2019,
<https://youtu.be/GFEgB_ytDZY>