Viral Diseases

The term ‘ACE2’ is talked about in the context of

[amp_mcq option1=”genes introduced in the genetically modified plants” option2=”development of India’s own satellite navigation system” option3=”radio collars for wildlife tracking” option4=”spread of viral diseases” correct=”option4″]

The term ‘ACE2’ stands for Angiotensin-converting enzyme 2. This enzyme is a protein found on the surface of many cells, particularly in the lungs, heart, kidneys, and intestines. It became widely known because it serves as the primary receptor that the SARS-CoV-2 virus (which causes COVID-19) uses to enter human cells. Therefore, ACE2 is talked about extensively in the context of the spread of viral diseases, specifically COVID-19.

– ACE2 is a protein enzyme found on cell surfaces.
– It acts as a receptor for coronaviruses, including SARS-CoV-2.
– The binding of the virus to ACE2 is the initial step in cellular infection.

ACE2 is part of the renin-angiotensin system (RAS), which plays a crucial role in regulating blood pressure and fluid balance. Research is ongoing to understand the complex interaction between SARS-CoV-2 and ACE2, and how it affects the RAS and contributes to the severity of COVID-19 disease.

Consider the following statements :

• Adenoviruses have single-stranded DNA genomes whereas retroviruses have double-stranded DNA genomes.
• Common cold is sometime caused by an adenovirus whereas AIDS is caused by a retrovirus.

Which of the statements given above is/are correct?

[amp_mcq option1=”1 only” option2=”2 only” option3=”Both 1 and 2″ option4=”Neither 1 nor 2″ correct=”option2″]

Statement 1 is incorrect, while statement 2 is correct.

– Statement 1: Adenoviruses are non-enveloped viruses with a *double-stranded* linear DNA genome. Retroviruses are enveloped viruses with a *single-stranded* RNA genome (typically two copies). They are called retroviruses because they use an enzyme called reverse transcriptase to convert their RNA genome into double-stranded DNA after infecting the host cell. Therefore, statement 1 is incorrect.
– Statement 2: Adenoviruses are one of the common causes of the common cold, along with rhinoviruses and coronaviruses. AIDS (Acquired Immunodeficiency Syndrome) is caused by the Human Immunodeficiency Virus (HIV), which is a well-known example of a retrovirus. Therefore, statement 2 is correct.

Adenoviruses can also cause other illnesses like conjunctivitis, bronchitis, and gastroenteritis. HIV primarily infects components of the human immune system, such as CD4+ T cells, macrophages, and dendritic cells, leading to progressive failure of the immune system.

Which one of the following statements is not correct?

[amp_mcq option1=”Hepatitis B virus is transmitted much like HIV.” option2=”Hepatitis B, unlike Hepatitis C, does not have a vaccine.” option3=”Globally, the number of people infected with Hepatitis B and C viruses are several times more than those infected with HIV.” option4=”Some of those infected with Hepatitis B and C viruses do not show the symptoms for many years.” correct=”option2″]

The correct option is B because the statement “Hepatitis B, unlike Hepatitis C, does not have a vaccine” is incorrect.

Vaccination is a highly effective way to prevent Hepatitis B infection. While there is no widely available prophylactic vaccine for Hepatitis C, research is ongoing.

A) Hepatitis B and HIV share similar transmission routes, including sexual contact, exposure to infected blood (e.g., through sharing needles), and mother-to-child transmission. This statement is correct.
B) There is a safe and effective vaccine available to prevent Hepatitis B infection. In contrast, there is currently no effective preventive vaccine for Hepatitis C, although treatments for Hepatitis C have significantly advanced. Thus, the statement that Hepatitis B *does not* have a vaccine is false.
C) According to WHO estimates, significantly more people globally live with chronic Hepatitis B and C infections compared to HIV. This statement is correct.
D) Both Hepatitis B and C infections can be asymptomatic for many years, with chronic liver damage occurring silently before symptoms appear. This statement is correct.

Consider the following statements:

• 1. In tropical regions, Zika virus disease is transmitted by the same mosquito that transmits dengue.
• 2. Sexual transmission of Zika virus disease is possible.

Which of the statements given above is/are correct?

[amp_mcq option1=”1 only” option2=”2 only” option3=”Both 1 and 2″ option4=”Neither 1 nor 2″ correct=”option3″]

Both statements 1 and 2 are correct.

– Statement 1 is correct. Zika virus is primarily transmitted to people through the bite of an infected Aedes species mosquito (Ae. aegypti and Ae. albopictus), which are the same types of mosquitoes that spread dengue, chikungunya, and yellow fever.
– Statement 2 is correct. Zika virus can be transmitted through sexual contact, from an infected person to their partner.

Other modes of Zika virus transmission include transmission from mother to fetus during pregnancy, through blood transfusion (though less common), and potentially through organ transplantation.

Which of the following statements is/are correct?
Viruses can infect

• bacteria
• fungi
• plants

Select the correct answer using the code given below.

[amp_mcq option1=”1 and 2 only” option2=”3 only” option3=”1 and 3 only” option4=”1, 2 and 3″ correct=”option4″]

The correct option is D, as viruses can infect bacteria, fungi, and plants.

– Viruses are obligate intracellular parasites that infect a vast range of living organisms across all domains of life.
– Statement 1 is correct: Viruses that infect bacteria are called bacteriophages.
– Statement 2 is correct: Viruses that infect fungi are called mycoviruses.
– Statement 3 is correct: Viruses that infect plants are called plant viruses and cause numerous plant diseases.

Viruses are highly specific in their hosts, with different types of viruses infecting different types of organisms. However, collectively, viruses can infect virtually all forms of cellular life, including bacteria, archaea, protists, fungi, plants, and animals.

H1N1 virus is sometimes mentioned in the news with reference to which one of the following diseases?

[amp_mcq option1=”AIDS” option2=”Bird flu” option3=”Dengue” option4=”Swine flu” correct=”option4″]

The H1N1 virus is the primary cause of swine flu.

H1N1 is an influenza A virus subtype that is the most common cause of human influenza (flu).

The 2009 swine flu pandemic was caused by a new strain of H1N1 that resulted from a mix of human, swine, and bird flu viruses. While H1N1 strains circulate in various animals, this particular strain was referred to as “swine flu” because genetic analysis showed it originated from pigs. Bird flu is typically caused by other influenza subtypes like H5N1. AIDS is caused by the Human Immunodeficiency Virus (HIV), and Dengue is caused by the Dengue virus, transmitted by mosquitoes.

Which of the following statements is/are correct?

• 1. Viruses lack enzymes necessary for the generation of energy.
• 2. Viruses can be cultured in any synthetic medium.
• 3. Viruses are transmitted from one organism to another by biological vectors only.

Select the correct answer using the codes given below.

[amp_mcq option1=”1 only” option2=”2 and 3 only” option3=”1 and 3 only” option4=”1, 2 and 3″ correct=”option1″]

Only statement 1 is correct: Viruses lack enzymes necessary for the generation of energy.

Statement 1 is correct. Viruses are acellular and obligate intracellular parasites. They do not possess their own metabolic machinery, including enzymes for energy production like respiration or fermentation. They hijack the host cell’s metabolic processes to obtain energy and replicate. Statement 2 is incorrect because viruses require living cells to replicate and cannot be cultured in synthetic non-living media. Statement 3 is incorrect because while biological vectors are one mode of transmission for some viruses, many viruses are transmitted through non-vector means such as direct contact, airborne droplets, contaminated surfaces, food, or water.

Viruses consist of genetic material (DNA or RNA) enclosed in a protein coat (capsid), and sometimes an outer envelope derived from the host cell membrane. Their dependence on host cells for replication and metabolism distinguishes them from cellular organisms like bacteria or fungi.