Free Biodiversity and Variety of Life MCQs with Answers

421. When were bacteriophages discovered by Twort?

• A. 1915
• B. 1920
• C. 1910
• D. 1820

Explanation: Bacteriophages were first discovered by Frederick W. Twort in 1915. While working with Staphylococcus colonies, he noticed that some of them suddenly became transparent and failed to grow. Twort suggested that this was caused by a "filterable virus" capable of destroying bacteria, although he was uncertain and did not pursue the finding further.

422. What type of virus is the smallpox virus?

• A. DNA-enveloped virus
• B. RNA-enveloped virus
• C. DNA non-enveloped virus
• D. RNA non-enveloped virus

Explanation: Viruses are classified by genome type and presence of an envelope. RNA-enveloped viruses (e.g., influenza, HIV) have RNA with a capsid and lipid coat, while RNA-non-enveloped viruses (e.g., polio, rotavirus) carry RNA only in a capsid. DNA-enveloped viruses (e.g., herpes, hepatitis B, and poxvirus) contain a large double-stranded DNA genome with both capsid and envelope, whereas DNA-non-enveloped viruses (e.g., adenovirus and papillomavirus) package DNA only in a protein shell. Notably, the poxvirus is a DNA-enveloped virus.

423. Binomial nomenclature was proposed for the first time by:

• A. Charles Darwin (1859)
• B. Rudolph virchow (1855)
• C. Louis Pasteur (1862)
• D. Carolus Linnaeus (1707)

Explanation: Tyrannosaurus rex is probably the most widely known binomial. The formal introduction of this system of naming species is credited to Carl Linnaeus, effectively beginning with his work Species Plantarum in 1753.

424. Which of the following best characterizes the viruses with un-enveloped plus- (I point) strand RNA?

• A. Lacking envelope
• B. Having DNA
• C. Act indirectly
• D. Enveloped

Explanation: Lacking envelope: As indicated by their name, un-enveloped plus-strand RNA viruses lack envelopes and consist only of a nucleic acid core capsid surrounded by protein viruses. Hence, this option is correct

425. Through which of the following does rabies spread?

• A. Cat
• B. Fox
• C. Dog
• D. Pig

Explanation: Rabies is most often spread by small, mammals such as dogs, racoons and foxes, most commonly by dogs.The rabies virus is spread by the saliva of the host animal, often after bites but it can also be contracted from handling a dead infected animal.

426. The hepatitis that passes from mother to her child during pregnancy is:

• A. Hepatitis A
• B. Hepatitis B
• C. Hepatitis C
• D. Hepatitis D

Explanation: Hepatitis B spreads through contact with infected body fluids. This includes blood, serum, saliva, breast milk, and it can also be passed on through sexual contact.

427. Which of the following may lead to death by the age of three years?

• A. Pompe disease
• B. Gaucher's disease
• C. Tay-Sachs disease
• D. Krabbe's disease

Explanation: Tay-Sachs disease is a genetic disorder where the enzyme Hexosaminidase A is absent. It causes progressive nerve damage, loss of motor skills, blindness, seizures, and death usually by age 3.

428. Which of the following is not related to enveloped viruses?

• A. They survive for a short time.
• B. They are tolerant to antibodies.
• C. Their envelope is sensitive to sunlight.
• D. Envelope is derived from host..

Explanation: Enveloped viruses are less resistant to antibodies or disinfectants and can be easily destroyed. The envelope is derived from the host and is sensitive to sunlight. They survive for a short time.

429. Which of the following is absent from membrane of prokaryotes?

• A. Glycolipid
• B. Cholesterol
• C. Glycoprotein
• D. Phospholipid

Explanation: Cholesterol is a component of eukaryotic cell membranes and is typically absent in prokaryotic cell membranes, such as those of bacteria.

430. Multicellular, heterotrophic nutrition, cell walls are never present in their cells, which kingdom do these organisms belong to?

• A. Kingdom Protista
• B. Kingdom Fungi
• C. Kingdom Plantae
• D. Kingdom Animalia

Explanation: Organisms with multicellular structures, heterotrophic nutrition, and the absence of cell walls in their cells belong to the Kingdom Animalia.