ALL PAST EXAM AND ASSIGNMENT QUESTION ANSWERED.
GUARNETEED 100% TEST SCORE WITH THIS GUIDE!
,QUESTION 1 [25]
1.1. Write explanatory notes on at least two important microbiological events that had a significant impact on
society and development of microbiology. [20]
Discovery of Penicillin:
In 1928, Alexander Fleming discovered Penicillin, a naturally occurring antibiotic produced by the fungus Penicillium.
This discovery revolutionized medicine and saved countless lives. Before the discovery of Penicillin, bacterial
infections were often fatal. The development of Penicillin and other antibiotics transformed medicine, allowing
doctors to treat and cure previously deadly bacterial infections such as pneumonia, syphilis, and tuberculosis. The
discovery of Penicillin led to the development of other antibiotics, and today antibiotics are widely used to treat a
range of bacterial infections. However, overuse of antibiotics has led to antibiotic resistance, one of the most
significant challenges in modern medicine. The discovery of Penicillin is considered one of the most important events
in the history of microbiology.
Germ theory of disease:
In the mid-19th century, Louis Pasteur and Robert Koch independently developed the germ theory of disease, which
revolutionized our understanding of infectious diseases. Before the germ theory of disease, it was widely believed
that diseases were caused by factors such as bad air, miasmas, and imbalances of the four humours. The germ
theory of disease showed that many diseases were caused by microorganisms such as bacteria, viruses, and
parasites. This discovery led to the development of better sanitation and hygiene practices, which helped to prevent
the spread of infectious diseases. The germ theory of disease also led to the development of vaccines, which have
saved millions of lives by preventing diseases such as smallpox, polio, and measles. The germ theory of disease is one
of the most important concepts in microbiology and has had a significant impact on public health and medicine.
1.2. What is your understanding of germ theory of disease? [5]
The germ theory of disease is the concept that microorganisms such as bacteria, viruses, fungi, and parasites are the
primary causes of many infectious diseases. This theory was developed in the mid-19th century by Louis Pasteur and
Robert Koch, who demonstrated that specific microorganisms were responsible for specific diseases. Prior to the
germ theory of disease, it was believed that diseases were caused by factors such as bad air or miasmas, and there
was little understanding of how infectious diseases spread. The germ theory of disease revolutionized our
understanding of infectious diseases and led to the development of better sanitation and hygiene practices, as well
as the development of vaccines and antibiotics to prevent and treat infectious diseases. The germ theory of disease
is now widely accepted and forms the basis for much of modern medicine and public health practice.
QUESTION 2 [25]
2.1. Discuss the distinguishing features and principal uses of TEM, SEM and Scanned-probe microscopy. [15]
There are several types of microscopy techniques used to observe the structure of cells and other biological
specimens. Three common types of microscopies are Transmission Electron Microscopy (TEM), Scanning Electron
Microscopy (SEM), and Scanned-probe Microscopy.
TEM:
Transmission Electron Microscopy (TEM) is a type of microscopy that uses a beam of electrons to image thin sections
of specimens. Electrons pass through the specimen and are refracted or absorbed by the densest areas, creating an
image that can be magnified up to 10,000,000 times. TEM is particularly useful for examining the internal structure
of cells and other subcellular components, such as organelles and macromolecules. It is commonly used in medical
research to investigate viruses, bacteria, and other microorganisms, as well as in materials science to study the
structure of metals, ceramics, and other materials.
SEM:
, Scanning Electron Microscopy (SEM) is a type of microscopy that uses a beam of electrons to create a high-resolution
image of the surface of a specimen. The electrons interact with the atoms on the surface of the specimen, creating a
three-dimensional image that can be magnified up to 100,000 times. SEM is particularly useful for studying the
surface structure and topography of cells and tissues, as well as for analysing the composition of materials. It is
commonly used in materials science to study the surface of materials, as well as in biology to study the surface
structure of cells and tissues.
Scanned-probe Microscopy:
Scanned-probe Microscopy is a type of microscopy that uses a physical probe to scan the surface of a specimen and
create an image. There are several types of scanned-probe microscopy, including Atomic Force Microscopy (AFM)
and Scanning Tunnelling Microscopy (STM). Scanned-probe microscopy is particularly useful for studying the
topography and mechanical properties of materials at a very high resolution. It is commonly used in materials
science to study the surface structure of materials, as well as in biology to study the structure and mechanical
properties of cells and tissues.
In summary, TEM is used to observe the internal structure of cells and subcellular components, SEM is used to
observe the surface structure and topography of cells and tissues, and scanned-probe microscopy is used to study
the surface structure and mechanical properties of materials and biological specimens. Each of these microscopy
techniques has unique features and applications, and they are all essential tools for investigating the structure and
function of biological and materials systems.
2.2. Describe how the minimum inhibitory concentration of an antibacterial agent is determined.
The minimum inhibitory concentration (MIC) is the lowest concentration of an antibacterial agent that inhibits the
growth of a particular microorganism. The MIC can be determined through a variety of methods, including broth
microdilution, agar dilution, and gradient diffusion.
Broth microdilution:
In broth microdilution, a series of test tubes containing different concentrations of the antibacterial agent are
inoculated with the microorganism of interest. The tubes are then incubated, and the lowest concentration of the
agent that inhibits visible growth of the microorganism is determined.
Agar dilution:
In agar dilution, a series of agar plates containing different concentrations of the antibacterial agent are inoculated
with the microorganism of interest. The plates are then incubated, and the lowest concentration of the agent that
inhibits visible growth of the microorganism is determined.
Gradient diffusion:
In gradient diffusion, a commercially available gradient strip containing a range of concentrations of the antibacterial
agent is placed on an agar plate inoculated with the microorganism of interest. The gradient strip diffuses the agent
into the agar, creating a concentration gradient. The minimum inhibitory concentration is determined by observing
the point at which the gradient intersects with the zone of bacterial growth.
In each of these methods, the MIC is determined by observing the lowest concentration of the antibacterial agent
that inhibits visible growth of the microorganism. The MIC is an important measure of the effectiveness of an
antibacterial agent and is used to guide the selection of appropriate treatment options for bacterial infections.
QUESTION 3 [30]
3.1. Name and discuss differential staining method that is used to detect the presence of the endospores. [10]
The differential staining method used to detect the presence of endospores is called the Schaeffer-Fulton staining
method. This method is since endospores are highly resistant to staining, and therefore require a special staining
technique to be visualized.
