Mutation in a virus is caused due to a change in its:
- A.cell size.
- B.genetic material.
- C.shape.
- D.colour.
Correct answer
Explanation
The correct answer is B, genetic material. A mutation is a change in the sequence of the DNA or RNA that carries a virus's genes.
A virus is made of genetic material, either DNA or RNA, inside a protein coat. When the virus copies itself inside a host cell, errors in copying change some of its bases; this is a mutation. RNA viruses such as influenza, HIV and coronaviruses mutate fast because their copying enzymes do not correct mistakes. Mutations create new variants, which is why flu vaccines are updated every year.
A is wrong because viruses are not cells and have no cell size; they are non-cellular particles.
C is wrong because shape is decided by the protein coat, which is itself built from genetic instructions; a change in shape is a result, not the mutation.
D is wrong because viruses are far too small to have any colour, and colour has nothing to do with mutation.
Exam tip: mutation = change in DNA/RNA sequence; RNA viruses mutate fastest.
Practice Questions
View allWhich one of the following cell organelles contains DNA?
- A.Golgi apparatus
- B.Mitochondrion
- C.Lysosome
- D.Endoplasmic reticulum
Show answer
Mitochondria carry their own small, circular DNA and their own ribosomes. Mitochondria are the powerhouses of the cell, where aerobic respiration makes ATP.
Read the full explanation →Which set of vegetables is underground stem or modified stem of a plant?
- A.Potato, artichoke, round gourd
- B.Onion, garlic, carrot
- C.Potato, onion, garlic
- D.Potato, garlic, turnip
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All three are underground modified stems: the potato is a stem tuber, and onion and garlic are bulbs. A stem can be told from a root by its nodes and buds.
Read the full explanation →A sound wave having frequency of 300 Hz is travelling in an unknown medium. Its wavelength is not known. It travels a distance equal to 150 times its wavelength in time t. The value of t is :
- A.0.5 s
- B.1 s
- C.1.5 s
- D.2 s
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A wave moves forward by one wavelength in each cycle, so 150 wavelengths take 150 cycles, and 150 cycles at 300 per second take half a second.
Read the full explanation →A body floats in a liquid if the buoyant force is :
- A.equal to its weight.
- B.less than its weight.
- C.greater than its weight.
- D.zero.
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A floating body is in equilibrium, so the upward buoyant force exactly balances its weight. By Archimedes' principle, a body in a liquid is pushed up by a force equal to the weight of the liquid it displaces.
Read the full explanation →Which of the following are the different parts of a human brain ?
- A.Forefront brain, Standard brain and Hind brain
- B.Fore brain, Median brain and Rear brain
- C.Fore brain, Mid brain and Hind brain
- D.Precursor brain, Mean brain and Hind brain
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These are the three main divisions of the human brain. The fore brain is the largest part.
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