Free Biodiversity and Variety of Life MCQs with Answers
3,130 Biodiversity and Variety of Life MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Biological classification uses taxonomic ranks, binomial nomenclature and shared characteristics to organize life into kingdoms. The major groups include prokaryotes, protists, fungi, plants and animals, with comparisons based on cell type, cell wall, nutrition, body organization, reproduction and evolutionary relationships; prokaryotes lack a membrane-bound nucleus.
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- A. Rod
- B. Conical
- C. Tadpole
- D. Spherical
Explanation: The tobacco mosaic virus (TMV) is a rod-shaped virus that is about 300 nanometers (nm) long and 18 nm in diameter.
Correct answer: Rod- A. Small
- B. Spherical
- C. Acellular
- D. DNA
Explanation: Poliovirus is a small, non-enveloped RNA virus belonging to the family Picornaviridae.
Correct answer: DNA- A. Virus
- B. Vision
- C. Bacteria
- D. Prion
Explanation: Mad cow disease, also known as bovine spongiform encephalopathy (BSE), is a fatal neurodegenerative disorder that affects cattle.
Correct answer: Prion- A. TMV
- B. Bacteriophage
- C. Herpes
- D. HBV
Explanation: The first virus to be crystallized was the Tobacco Mosaic Virus (TMV), discovered by Wendell Stanley in 1935.
Correct answer: TMV- A. Protein
- B. DNA
- C. Nucleoprotein
- D. RNA
Explanation: Viroids are the smallest known infectious agents, consisting solely of a short, circular strand of single-stranded RNA without any protein…
Correct answer: RNA- A. All viruses
- B. Bacteriophages
- C. Retroviruses
- D. Plant viruses
Explanation: Reverse transcriptase is an enzyme contained in retroviruses, such as HIV (Human Immunodeficiency Virus).
Correct answer: Retroviruses587. AIDS will lead to:
- A. Liver cirrhosis
- B. Mental retardation
- C. Opportunistic infections
- D. Angina
Explanation: The consequences of AIDS arise from the severe weakening of the immune system due to the loss of CD4+ T cells.
Correct answer: Opportunistic infections- A. DNA
- B. RNA
- C. DNA or RNA
- D. DNA and RNA
Explanation: In viruses, the type of genetic material-either RNA or DNA-is a key feature that determines their classification.
Correct answer: DNA or RNA- A. RNA
- B. Proteins
- C. Nucleoproteins
- D. DNA
Explanation: Bacteriophages, the viruses that infect bacteria, are composed of nucleic acids and proteins, which together form their structure.
Correct answer: Nucleoproteins590. AIDS is due to:
- A. Deficiency of T lymphocytes
- B. Bacterial infection
- C. Deficiency of riboflavin
- D. High blood pressure
Explanation: The deficiency of CD4+ T lymphocytes during HIV infection occurs through multiple mechanisms.
Correct answer: Deficiency of T lymphocytes- A. K. M. Smith
- B. Twart
- C. M. Stanley
- D. Ivanowsky
Explanation: The discovery of viruses dates back to the late 19th century, when scientists were investigating diseases in plants that could not be…
Correct answer: Ivanowsky- A. Multiply only in host cells
- B. Behave as if they are plants
- C. They are made up of proteins only
- D. It occurs only inside bacteria
Explanation: Viruses are unique infectious agents with certain defining features, and among the given statements, the correct one is that they multiply…
Correct answer: Multiply only in host cells- A. Single-stranded RNA
- B. Double-stranded RNA
- C. Double-stranded DNA
- D. Single-stranded DNA
Explanation: The genetic material of retroviruses, including the AIDS-causing Human Immunodeficiency Virus (HIV), is single-stranded RNA (ssRNA).
Correct answer: Single-stranded RNA- A. Fungi
- B. Tapeworms
- C. Viruses
- D. Bacteria
Explanation: Interferons are produced mainly in response to viral infections because host cells recognize viral nucleic acids, such as double-stranded…
Correct answer: Viruses- A. RNA primase
- B. Reverse transcriptase
- C. RNA polymerase
- D. Viral nuclease
Explanation: The correct option is RNA polymerase. Most RNA viruses carry a gene for the enzyme RNA-dependent RNA polymerase (RdRp), which uses viral…
Correct answer: RNA polymerase- A. RNA is the primary genetic material in bacteria
- B. RNA is the genetic material for all viruses
- C. DNA is the genetic material for the majority of living organisms
- D. Some viruses use RNA as their genetic material
Explanation: Some viruses use RNA as their genetic material. Viruses can contain either DNA or RNA, depending on the type.
Correct answer: Some viruses use RNA as their genetic material- A. Animal virus
- B. Plant virus
- C. Bacteriophage
- D. Viroid
Explanation: The correct option is an animal virus. HIV is a retrovirus that infects human immune cells (CD4+ T cells) and causes AIDS.
Correct answer: Animal virus- A. DNA-dependent RNA polymerase
- B. DNA-dependent DNA polymerase
- C. RNA-dependent RNA polymerase
- D. RNA-dependent DNA polymerase
Explanation: Reverse transcriptase is an enzyme found in all retroviruses that enables them to replicate by converting their RNA genome into…
Correct answer: RNA-dependent DNA polymerase599. Bacteriophages kill:
- A. Fungi
- B. Parasites
- C. Bacteria
- D. Viruses
Explanation: Bacteriophages, or phages, specifically kill bacteria because they are viruses that are highly specialized to infect only bacterial cells.
Correct answer: Bacteria- A. Bacteria
- B. Viruses
- C. Slime moulds
- D. Cyanobacteria
Explanation: Viruses are obligate intracellular parasites because they lack the cellular structures and metabolic machinery needed to grow and…
Correct answer: Viruses