CURRENT RESEARCH JOURNAL OF PEDAGOGICS (ISSN: 2767-3278)
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40
VOLUME:
Vol.06 Issue06 2025
10.37547/pedagogics-crjp-06-06-10
Page: - 40 -44
RESEARCH ARTICLE
Molecular Structure and Some Properties of Viruses
Ahmadova Z.Sh.
Researcher at the National Pedagogical University of Uzbekistan named after Nizami, Uzbekistan
Received:
30 April 2025
Accepted:
28 May 2025
Published:
30 June 2025
INTRODUCTION
Although both bacteria and viruses can harm our bodies,
they differ biologically. Bacteria are small, single-celled
organisms considered living because they can reproduce
without needing a host cell. Due to these differences,
diseases caused by bacteria and viruses are treated
differently. For example, antibiotics are only effective
against bacteria, not viruses.
Viruses are tiny, infectious structures that can only
reproduce by infecting a host cell. They invade host cells
and use them as a resource to produce new viruses.
Because viruses cannot reproduce without a host organism,
they are not considered living organisms. They also do not
have cells of their own: viruses are much smaller than
living cells and are made up of proteins and nucleic acids.
However, viruses do have some characteristics similar to
living, cell-based organisms. For example, like us, they
also possess genetic material in the form of nucleic acids
and have a genome. Additionally, they are highly diverse
and have the ability to evolve. Although viruses do not
display all the characteristics of life, they are still
considered a “questionable” form of life [4].
Viruses are microscopic, infectious agents that can
replicate only by infecting a host cell. They hijack the
host’s cellular machinery to produce new virus particles,
utilizing the cell’s resources for their own replication.
Because they are incapable of independent reproduction
without a host, viruses are generally not classified as living
organisms. Moreover, viruses lack cellular structure; they
are significantly smaller than living cells and are composed
primarily of proteins and nucleic acids.
Despite this, viruses exhibit several traits similar to those
of cellular life forms. For instance, they contain genetic
material—either DNA or RNA—organized into a genome,
and their replication is governed by a genetic code similar
to that of living organisms. Furthermore, viruses are highly
diverse and possess the ability to evolve over time.
Although they do not fulfill all the criteria typically
associated with life, viruses remain a subject of ongoing
scientific debate regarding their classification as living or
non-living entities.
Virology is the study of viruses and virus-like agents,
including, but not limited to, their taxonomy, disease-
producing properties, cultivation, and genetics. Virology is
often considered a part of microbiology or pathology.
During the early years of virology, this discipline was
dependent upon advances in the chemical and physical
sciences; however, viruses soon became tools for probing
basic biochemical processes of cells. Viruses have
traditionally been viewed in a rather negative context as
agents responsible for diseases that must be controlled or
ABSTRAC
The paper involves general information about the general characteristics of viruses and the types of disea ses and harms they
cause. It also provides information about the molecular structure of viruses and the importance of DNA or RNA, which is the
genetic information, in causing disease, and the important role that prions play in maintaining the infectivity o f the virus.
Keywords:
Viruses, prions, polymers, morphology, hepatitis virus, COVID-19.
CURRENT RESEARCH JOURNAL OF PEDAGOGICS (ISSN: 2767-3278)
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eliminated. However, viruses also have certain beneficial
properties that can be exploited for useful purposes, as is
evident in both gene therapy and vaccinology.
In general, viruses contain only one type of nucleic acid
(either DNA or RNA) that carries the information
necessary for viral replication. Nevertheless, it is clear now
that some viruses contain other nucleic acid molecules; for
example, in retroviruses, cellular transfer RNAs are
essential for the action of the enzyme reverse transcriptase.
The chemical composition of viruses varies between
different virus families. For the simplest of viruses, the
virion is composed of viral structural proteins and nucleic
acid; however, the situation becomes more complex with
when dealing with enveloped viruses. The latter types of
viruses mature by budding through different cellular
membranes that are modified by the insertion of viral
proteins. Several properties should be considered most
important in constructing a scheme for the classification of
all the viruses. These include the nature of the nucleic acid
present in the virion, the symmetry of the protein shell,
dimensions of the virus particle, as well as the presence or
absence of a lipid membrane.
The International Committee on Viral Taxonomy (ICTV),
which was given the task of developing a universal
taxonomic scheme for all the viruses, has put an emphasis
on the viral genome, which is a blueprint for producing
new virusesm as a basis of all classification decisions. In
formal virus taxonomy, families, subfamilies, and genera
are always written in italics, with the first letters of the
names capitalized. Instead of formal names (e.g.
Parvoviridae), common names are often used for viruses,
as can be seen in the various different kinds of medical
literature (e.g. parvoviruses) [1].
Theoretical bases
. Even from the earliest times, it was
clear that the filterable agents could not be cultivated on
artificial media. Even today, virus isolation in cell culture
is still considered the gold standard against which other
assays must be compared.
Still, the most obvious method of virus detection and
identification is direct visualization of the agent. The
morphology of most viruses is sufficiently characteristic to
identify the image as a virus and to assign an unknown
virus to the appropriate family (Picture.1). Furthermore,
certain non-cultivable viruses can be detectable by electron
microscopy. The culture of animal cells typically involves
the use of a culture medium containing salts, glucose,
vitamins, amino acids, antimicrobial drugs, buffers, and,
typically, blood serum, which provides a source of
necessary cellular growth factors. For certain cell-lines,
defined serum-free media have been developed, which
contain specific growth factors without requiring the
addition of blood serum into the medium.
Serological tests are used to show the presence or absence
of antibodies to a specific virus. The presence of certain
antibodies indicates exposure to the agent, which may be
due to a current clinical condition or as a result of an earlier
unrelated infection. Some tests that can be used to identify
viral antibodies include hemagglutination, complement
fixation tests, radioimmunoassays, immunofluorescence,
enzyme-linked
immunosorbent
assay
(ELISA),
radioimmune precipitation, and Western blot assays.
CURRENT RESEARCH JOURNAL OF PEDAGOGICS (ISSN: 2767-3278)
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Picture 1. The morphology of virus.
Molecular techniques such as polymerase chain reaction
(PCR) are also widely used for both the detection of an
active virus as well as to determine whether any antibodies
against the virus are present. Some of the different
applications of PCR tests can be found in diagnostic
clinical virology, as well as for research purposes. The use
of such nucleic acid-centered technology offers substantial
advances in the detection of viruses and can be further
enhanced with the incorporation of certain nucleic acid
hybridization techniques [2].
We look at some Hepatitis virus kinds in the below.
Hepatitis C is caused by hepatitis C virus (HCV), which
has a 50-nm enveloped virion that contains a single strand
of linear RNA. HCV is a member of the family
Flaviviridae. It is transmitted by use of contaminated
needles (drug use, tattoo parlors), by in utero transmission
from mother to fetus, or through organ transplantation. It is
rarely sexually transmitted because HCV requires blood-
to-blood contact. Screening for HCV is performed by
detection of anti-HCV antibodies. Positive results are then
confirmed by HCV nucleic acid amplification to determine
viral load. Worldwide, hepatitis C has reached epidemic
proportions, with about 70 million people chronically
infected. In the United States, HCV is the most common
chronic blood-borne infection; approximately 3 million
persons are chronically infected and 20,000 new cases
occur annually. Like HBV, HCV infection can cause
hepatocellular carcinoma. HCV is currently the leading
reason for liver transplantation in the United States. There
are six major genotypes with genotype 1 the most common,
followed by genotype 3. Treatment for genotype 1 disease
is with the drug combination of sofosbuvir (a nucleotide
analogue polymerase inhibitor) and ledipasvir (an HCV
replication inhibitor). A 12-week treatment with this drug
combination results in complete cure of the virus from the
host. Other genotypes are also usually treated for 12 weeks
with sofosbuvir, coupled with velpatasvir, which has a
similar mechanism to ledipasvir.
Hepatitis delta virus (HDV) was discovered in 1977 and
the disease hepatitis D was designated. There are eight
known genotypes of HDV: Genotype 1 has a worldwide
distribution; genotypes 2 and 4 exist in East Asia; genotype
3 is found in South America; and genotypes 5 through 8
are in Africa. All genotypes can cause acute as well as
chronic liver disease. HDV is a satellite virus that is
dependent on hepatitis B virus to provide the surface
protein (HBsAg) for its own replication. HDV’s
dependence on HBV means that HDV only replicates in
liver cells coinfected with actively replicating HBV. HDV
is spread only to persons who are already infected with
HBV (superinfection) or when HBV and the satellite are
transmitted together (coinfection). The negativestrand
RNA of HDV is smaller than the RNA of the smallest
picornaviruses, and its circular conformation differs from
the linear structure typical of animal negative-strand RNA
viruses. The primary laboratory tools for diagnosis of an
HDV infection are serological tests for anti-HDV
antibodies. Treatment of patients mirrors that of HBV-
infected patients. About 5% of all those with hepatitis B
are coinfected with HDV. Prevention and control involve
CURRENT RESEARCH JOURNAL OF PEDAGOGICS (ISSN: 2767-3278)
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43
the widespread use of the hepatitis B vaccine.
Hepatitis A. Hepatitis A (infectious hepatitis) usually is
transmitted by fecal contamination of food or drink, or
shellfish that live in contaminated water. The disease is
caused by hepatitis A virus (HAV) of the genus
Hepatovirus in the family Picornaviridae. Recall that while
all hepatitis viruses can cause liver disease, they are not
taxonomically related (table 37.1). HAV is an icosahedral,
linear, positive-strand RNA virus that lacks an envelope.
Once in the digestive system, the virus multiplies within
the intestinal epithelium. Usually only mild intestinal
symptoms result. Occasionally viruses are found in the
blood (viremia) and may spread to the liver. The virus
reproduces in the liver, enters the bile, and is released into
the small intestine. This explains why feces are so
infectious. After about a 4-week incubation period,
symptoms develop that include anorexia, general malaise,
nausea, diarrhea, fever, chills, and jaundice. Most cases
resolve in 4 to 6 weeks and yield a strong immunity,
although some patients relapse, exhibiting symptoms for 6
months or more. The mortality rate is low (less than 1%),
and about 40 to 80% of the U.S. population has antibodies,
though few are aware of having had the disease. Control of
infection is by simple hygienic measures, the sanitary
disposal of excreta, and the HAV vaccine. The number of
new cases has been dramatically reduced since the
introduction of the hepatitis A vaccine in the 1990s. This
vaccine is recommended for travelers (see table 35.2)
going to regions with high rates of hepatitis A.
Hepatitis E. Hepatitis E caused by hepatitis E virus (HEV)
genotypes 1 and 2 is implicated in many epidemics in
countries with limited clean water and sanitation, while
genotypes 3 and 4 are found in Europe and, to a lesser
extent, the United States. The single, positive-strand RNA
viral genome (7,900 nucleotides) is linear. The virion is
spherical, nonenveloped, and 32 to 34 nm in diameter
(table 37.1). Infection with HEV genotypes 1 and 2 usually
is associated with feces-contaminated drinking water,
whereas genotypes 3 and 4 are transmitted by
contaminated food (particularly undercooked pork). HEV
enters the blood from the gastrointestinal tract, replicates
in the liver, is released from hepatocytes into the bile, and
is subsequently excreted in the feces. Like hepatitis A, an
HEV infection usually runs a benign course and is
selflimiting. The incubation period varies from 15 to 60
days, with an average of 40 days. The disease is most often
seen in patients who are 15 to 40 years of age. Children are
typically asymptomatic or present mild signs and
symptoms, including abdominal pain, anorexia, dark urine,
fever, enlarged liver, jaundice, malaise, nausea, and
vomiting. Case fatality rates are low (1 to 3%), except for
pregnant women (15 to 25%), who risk death from
fulminant hepatic failure. Diagnosis of HEV infection is by
detection of anti-HEV antibodies or reverse transcriptase
PCR. There are no specific measures for preventing HEV
infections, other than those aimed at improving the level of
health and sanitation in affected areas.
Ebola Virus and Marburg Diseases
Ebola virus disease (EVD) is caused by Ebola viruses, first
recognized near the Ebola River in the Democratic
Republic of the Congo in Africa. They are members of the
genus Ebolavirus in the family Filoviridae, a group of
filamentous, negative-strand RNA viruses (figure 37.23).
Six Ebola species are known: Sudan ebolavirus, Tai Forst
ebolavirus
(formerly
Côte
d’Ivoire
ebolavirus),
Bundibugyo ebolavirus, Zaire ebolavirus, Bombali
ebolavirus, and Reston ebolavirus. Members of the first
five species cause disease in humans. The sixth, Reston
ebolavirus, was first discovered in 1989, and to date Reston
viruses have caused disease only in nonhuman primates
and pigs. Only Reston virus is spread by aerosol
transmission. All Ebola virus that infect humans are
transmitted by contact with div fluids. Convalescing
patients continue to harbor virus in div fluids and in rare
instances there has been sexual transmission through
infected semen up to 17 months after recovery. Bats are
thought to be the natural reservoir for Ebola viruses,
although the exact species is not known.
Viral hemorrhagic fever (VHF) is the term used to describe
the severe, multisystem syndrome seen in Ebola
epidemics. Because the host vascular system is damaged,
vascular leakage of fluids into div tissues accompanied
by the blood’s diminished ability to clot (coagulopathy)
occurs. The incubation period for EVD ranges from 2 to 21
days and is characterized by abrupt fever, headache, joint
and muscle aches, sore throat, and weakness, followed by
diarrhea, vomiting, and stomach pain. Signs of infection
include fever, rash, red eyes, bleeding, and hiccups—
symptoms alerting of internal hemorrhage. There is no
standard treatment for Ebola infection. Patients receive
supportive therapy consisting of balancing patients’ fluids
and electrolytes, maintaining their oxygen status and blood
pressure, and treating any complicating infections.
Convelscent sera, collected from Ebola survivors, and
experimental antidiv cocktails demonstrated promising
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44
success in the 2014 treatments of ebolaviruspatients. A
highly effective vaccine is now used to control outbreaks.
Marburg disease is caused by a genetically unique RNA
virus also in the Filoviridae family. Marburgvirus (MARV)
similarly causes a hemorrhagic fever. It is a rare, severe
type of hemorrhagic fever that affects both humans and
nonhuman primates. MARV was first recognized in 1967,
when
outbreaks
of
hemorrhagic
fever
occurred
simultaneously in laboratories in Marburg and Frankfurt,
Germany, and in Belgrade, Serbia. The first people
infected had been exposed to African green monkeys or
their tissues. MARV is indigenous to Africa, and the
reservoir host of MARV is the African fruit bat, Rousettus
aegyptiacus. The average incubation period for Marburg
hemorrhagic fever is 5 to 10 days. The disease symptoms
are abrupt, marked by fever, chills, headache, myalgia, and
a maculopapular rash (i.e., discolored with bumps).
Nausea, vomiting, chest pain, sore throat, abdominal pain,
and diarrhea may also occur in infected patients.
Symptoms become increasingly severe and may include
jaundice, delirium, liver failure, pancreatitis, severe weight
loss, shock, and multiorgan dysfunction [3].
CONCLUSION
Human immunodeficiency virus (HIV) is pandemic. HIV
has also brought changes that are not so obvious. For
example, HIV research led to much of our current
understanding of the immune system, which in turn is
yielding new and promising cancer treatments. HIV
disrupted the pharmaceutical industry as developing
nations began manufacturing their own life-saving
antiretroviral drugs that were otherwise too expensive to
provide to their citizens.
Viruses have significant biological and economic
importance. They cause numerous diseases, including
HIV/AIDS, influenza, COVID-19, and other infectious
illnesses in humans. In animals, viruses can also harm
livestock and forest plants. Viruses play an important role
in ecosystems as well, as they help regulate the growth and
decline of certain plant and animal populations [5].
In addition, viruses are used as valuable tools in
biotechnology—for example, in genetic modification,
vaccine production, and other scientific research.
The taxonomy of viruses is of great importance because it
provides a framework that places and connects all viruses
according to their clinical, biological, and evolutionary
characteristics. This concept has significant practical
implications. For example, when a virus emerges in
humans from an animal reservoir, from a taxonomic
perspective, it helps us better understand how it originated,
from which host it emerged, how it replicates, how it
causes disease, and how humans respond to infection. As a
result, we are in a much better position to develop
treatments and produce vaccines [6].
A current example is the novel coronavirus causing the
COVID-19 pandemic, the severe acute respiratory
syndrome coronavirus 2 (SARS-CoV-2). Taxonomy has
helped us understand that the natural host of this virus may
be bats and that its genetic material (genome) has evolved
through the combination of different parental genomes
(genetic recombination). Additionally, knowing that the
new coronavirus is closely related to the SARS coronavirus
that emerged in 2003 allowed for the reuse of antiviral
drugs such as remdesivir in the treatment of COVID-19.
Conclusion: This article has covered the transmission of
diseases through viruses, what symptoms they cause, and
how to protect yourself from them, especially by gathering
information about the harmful effects of dangerous viruses
on the div.
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Carter J, Saunders VA. Virology: Principles and
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Condit RC. Principles of Virology. In: Knipe DM, Howley
PM, editors. Fields’ Virology, Volume 1. Lippincott
Williams & Wilkins, 2007; pp. 25-58.
Joanne
M.Willey,
Kathleen
M.Sandman,
Dorothy
H.Wood. Prescott’s Microbiology. McGraw Hill LLC,
1325 Avenue of the Americas, New York, NY 10019.
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https://uz.council.science/blog/whats-the-point-of-virus-
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