Applied Science Unit 18 Microbiology
Damisi Oloniyo
P1- Identify the main groups of Microorganisms
Virus
The only place a virus can develop and reproduce is inside a living thing. The smallest known
bacterium that can cause illness is referred to as an akaryote. A virus needs to enter a host
cell in order to spread infection and illness. As soon as the virus enters the host cell, it begins
to copy its genetic material using the metabolic functions of the host cell before exiting.
Thereafter, by budding, the virus is able to infect the entire body. 1 The host cell will
gradually lose its plasma membrane as a result of this process, which typically results in cell
death. Viruses include, for instance, the flu, the common cold, and SARS.2
Virus Capsids
A virus's capsid is made up of many protein components. These proteins work together to
build the capsid when they come together. The viral cell that delivers the instructions for
their production also encodes these proteins. Several kinds of capsids exist:
• Icosahedral: The twenty-faced form of these capsids gives them their name.
Adenovirus and poliovirus are only two examples of these viruses.
• They are called filamentous because of their straight, thread-like appearance. Also
known as rod or helical. One manifestation of this virus is in tobacco mosaic virus
• These capsids have a head and a tail, combining the two earlier forms. They feature
a filamentous tail and an icosahedral head. Bacteriophage is a kind of virus that fits
this description.3
Figure 1: different capsids4
Figure 2: Structure of a virus cell5
1
, Applied Science Unit 18 Microbiology
Damisi Oloniyo
• Envelope Proteins: These proteins cover the cell's surface and aid in the virus's
attachment to certain receptors on the surface of the host cell. Moreover, they aid in
preventing nucleases from destroying DNA and RNA.6
• Envelope: this is a phospholipid bilayer that is surrounding the cell and the infectivity
of the virus increases7
• Viral Genome: The function of this is to transport and translate DNA and RNA into
the host cell. This allows the host cell to replicate and reproduce the genome.8
• Nucleocapsid: A common location for this viral structure within the cytoplasm is. It
encircles the viral genome and aids in its transmission to the host cell by fusing with
the membrane of the latter.9
• Viral Tegument: The tegument is liberated into the cytoplasm immediately after
infection. It is employed to assist the virus in dodging the immunological reaction of
the host cell. 10
Bacteria
Bacteria are tiny, single-celled creatures that may survive in a variety of conditions. As they
lack a nucleus and membrane-bound organelles, their cell structure is more simpler than
that of other species. Moreover, they store their genetic material in the form of plasmids,
which are single DNA loops. They divide into two identical cells in a process known as binary
fission, which is how they reproduce. Bacteria come in the following five shapes: spherical,
rod, spiral, comma, and corkscrew. Bacteria examples include salmonella, TB, and E. coli. 11
Bacteria come in a wide variety of varieties. One approach to categorise them is according
to form. The primary forms are three:
•
Spherical: A single bacterium is referred to as a coccus, while bacteria with a ball-like
form are known as cocci. The streptococcus genus, which causes "strep throat," is
one example.
•
They are referred to as spirilla (singular spirillus). Spirochetes are what they are
called when their coil is extremely tight. This kind of bacterium can cause syphilis,
leptospirosis, and Lyme disease.
1
Damisi Oloniyo
P1- Identify the main groups of Microorganisms
Virus
The only place a virus can develop and reproduce is inside a living thing. The smallest known
bacterium that can cause illness is referred to as an akaryote. A virus needs to enter a host
cell in order to spread infection and illness. As soon as the virus enters the host cell, it begins
to copy its genetic material using the metabolic functions of the host cell before exiting.
Thereafter, by budding, the virus is able to infect the entire body. 1 The host cell will
gradually lose its plasma membrane as a result of this process, which typically results in cell
death. Viruses include, for instance, the flu, the common cold, and SARS.2
Virus Capsids
A virus's capsid is made up of many protein components. These proteins work together to
build the capsid when they come together. The viral cell that delivers the instructions for
their production also encodes these proteins. Several kinds of capsids exist:
• Icosahedral: The twenty-faced form of these capsids gives them their name.
Adenovirus and poliovirus are only two examples of these viruses.
• They are called filamentous because of their straight, thread-like appearance. Also
known as rod or helical. One manifestation of this virus is in tobacco mosaic virus
• These capsids have a head and a tail, combining the two earlier forms. They feature
a filamentous tail and an icosahedral head. Bacteriophage is a kind of virus that fits
this description.3
Figure 1: different capsids4
Figure 2: Structure of a virus cell5
1
, Applied Science Unit 18 Microbiology
Damisi Oloniyo
• Envelope Proteins: These proteins cover the cell's surface and aid in the virus's
attachment to certain receptors on the surface of the host cell. Moreover, they aid in
preventing nucleases from destroying DNA and RNA.6
• Envelope: this is a phospholipid bilayer that is surrounding the cell and the infectivity
of the virus increases7
• Viral Genome: The function of this is to transport and translate DNA and RNA into
the host cell. This allows the host cell to replicate and reproduce the genome.8
• Nucleocapsid: A common location for this viral structure within the cytoplasm is. It
encircles the viral genome and aids in its transmission to the host cell by fusing with
the membrane of the latter.9
• Viral Tegument: The tegument is liberated into the cytoplasm immediately after
infection. It is employed to assist the virus in dodging the immunological reaction of
the host cell. 10
Bacteria
Bacteria are tiny, single-celled creatures that may survive in a variety of conditions. As they
lack a nucleus and membrane-bound organelles, their cell structure is more simpler than
that of other species. Moreover, they store their genetic material in the form of plasmids,
which are single DNA loops. They divide into two identical cells in a process known as binary
fission, which is how they reproduce. Bacteria come in the following five shapes: spherical,
rod, spiral, comma, and corkscrew. Bacteria examples include salmonella, TB, and E. coli. 11
Bacteria come in a wide variety of varieties. One approach to categorise them is according
to form. The primary forms are three:
•
Spherical: A single bacterium is referred to as a coccus, while bacteria with a ball-like
form are known as cocci. The streptococcus genus, which causes "strep throat," is
one example.
•
They are referred to as spirilla (singular spirillus). Spirochetes are what they are
called when their coil is extremely tight. This kind of bacterium can cause syphilis,
leptospirosis, and Lyme disease.
1
