Rabies virus is usually transmitted to humans through ____.
Correct answer B. the bite of an infected animal such as a dog
Topic / 45 questions
Acellular Life (Viruses) MCQs
Acellular Life MCQs are multiple-choice questions on viruses, covering their discovery, structure, classification, replication and the diseases they cause, with special focus on HIV and AIDS. Every question on MCQs360 shows the correct answer instantly, so you can test yourself and correct mistakes as you go.
- Biological Molecules 74
- Coordination and Control 72
- Biology Diagnostic 70
- Cell Structure and Function 67
- Biotechnology 65
- Reproduction 58
- Bioenergetics 55
- Circulation 50
- Inheritance 48
- Digestion 45
- Immunity 45
- Support and Movement 45
- Acellular Life (Viruses) 45
- Homeostasis 45
- Respiration and Gaseous Exchange 45
- Evolution 45
- Enzymes 45
- Cell Cycle 41
- Chromosome and DNA 40
- Biology Introduction 38
- Ecosystem 27
Which condition is typical of the later stage of AIDS?
Correct answer D. Pneumocystis pneumonia and Kaposi's sarcoma
A few weeks after HIV infection, many people first show ____.
Correct answer D. a short flu-like illness with fever and swollen lymph nodes
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Zidovudine (AZT), used to treat HIV infection, acts by inhibiting ____.
Correct answer C. reverse transcriptase
Antibiotics are ineffective against viral infections because viruses ____.
Correct answer A. lack the cell walls, ribosomes and enzymes that antibiotics target
Poliovirus enters the body mainly through contaminated food and water and may damage ____.
Correct answer B. motor neurons of the spinal cord
Swelling of the parotid salivary glands is the characteristic sign of which viral disease?
Correct answer A. Mumps
Hepatitis B virus is most commonly transmitted through ____.
Correct answer C. infected blood and sexual contact
Dengue fever is caused by a virus carried from person to person by ____.
Correct answer C. Aedes mosquitoes
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Which viral disease was declared eradicated worldwide in 1980 after a global vaccination campaign?
Correct answer D. Smallpox
A virulent bacteriophage differs from a temperate one in that it ____.
Correct answer B. always destroys its host by the lytic cycle
A phage such as lambda that can either lyse its host or enter lysogeny is known as a ____ phage.
Correct answer B. temperate
How is a prophage passed on to new bacterial cells?
Correct answer A. It is replicated with the bacterial chromosome at each cell division
Exposure of lysogenic bacteria to ultraviolet light often causes ____.
Correct answer C. the prophage to excise and start a lytic cycle
A bacterium carrying a prophage in its chromosome is described as ____.
Correct answer C. lysogenic
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HIV is placed in the retrovirus group because it ____.
Correct answer D. copies its RNA genome into DNA using reverse transcriptase
Which enzyme of HIV inserts the viral DNA into the chromosome of the host cell?
Correct answer D. Integrase
The genome of a single HIV particle consists of ____.
Correct answer A. two copies of single-stranded RNA
Which cells of the immune system are the principal target of HIV?
Correct answer A. Helper T lymphocytes carrying CD4
Which HIV envelope glycoprotein binds to the CD4 receptor of a host cell?
Correct answer D. gp120
About Acellular Life (Viruses) MCQs
Questions begin with the discovery of viruses, including Ivanovsky's work on tobacco mosaic disease and Stanley's crystallisation of tobacco mosaic virus, then move to virus structure: the nucleic acid core, the protein capsid made of capsomeres, envelopes and helical or polyhedral symmetry. Classification by DNA or RNA and by single or double strands is tested often. Bacteriophage questions compare the lytic and lysogenic cycles, prophages and the T4 phage. The HIV section covers its retrovirus nature, reverse transcriptase and integrase, its attack on helper T cells, modes of transmission and the stages of AIDS. Other questions deal with hepatitis, polio, rabies, smallpox and how viral diseases are prevented.
Key facts to remember
- Viruses are acellular and can reproduce only inside living host cells, so they are obligate intracellular parasites.
- Tobacco mosaic virus has a single-stranded RNA genome and a helical capsid.
- HIV is a retrovirus: its reverse transcriptase copies the viral RNA into DNA.
- HIV mainly infects helper T cells that carry the CD4 receptor.
- In the lysogenic cycle, phage DNA joins the host chromosome as a prophage and is copied each time the bacterium divides.
- The World Health Organization declared smallpox eradicated in 1980.
Exams that include Acellular Life (Viruses) MCQs
Pakistan
- MDCAT
- NUMS
- AKU
- FSc boards
India
- NEET
Bangladesh
- HSC
- Medical Admission Test
How to prepare for Acellular Life (Viruses) MCQs
- Make a table of common viral diseases with the virus type, mode of transmission and main organ affected.
- Draw the lytic and lysogenic cycles side by side and label where they differ.
- Learn the HIV life cycle step by step, naming the enzyme that acts at each stage.
- Memorise the key discoverers and their findings, such as Ivanovsky and Stanley, as these appear as quick recall questions.
Frequently asked questions
Which exams ask Acellular Life MCQs?
In Pakistan, Acellular Life questions appear in MDCAT, the NUMS and AKU entry tests and FSc board papers. Students in India meet the same content in NEET, and in Bangladesh it is tested in HSC Biology and the Medical Admission Test.
Why are viruses called acellular?
Viruses have no cell membrane, cytoplasm or ribosomes and carry out no metabolism of their own. They consist of a nucleic acid, either DNA or RNA, inside a protein coat, and they can multiply only by taking over the machinery of a living host cell.
How is HIV transmitted?
HIV spreads through unprotected sexual contact, transfusion of infected blood, sharing contaminated needles or syringes, and from an infected mother to her baby during pregnancy, birth or breastfeeding. It is not spread by casual contact such as shaking hands or sharing food.
Last reviewed October 2026