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300 questions in this collection · Page 15 of 30
Question 141 of 300
📘 CLASS XI
Biological Classification
Which scientist proved in 1935 that viruses could be crystallized and that these crystals largely consist of proteins?
W.M. Stanley successfully crystallised viruses in 1935.
Question 142 of 300
📘 CLASS XI
Biological Classification
A virus is an infectious nucleoprotein. Regarding its genetic material, which statement is true?
Viruses possess either RNA or DNA as genetic material, but never both simultaneously.
Question 143 of 300
📘 CLASS XI
Biological Classification
Viruses that infect bacteria (bacteriophages) generally contain which type of genetic material?
Most bacteriophages possess double-stranded DNA.
Question 144 of 300
📘 CLASS XI
Biological Classification
The protective protein coat of a virus is called a ____, and it is made of small subunits called ____.
The viral protein coat is the capsid, which is composed of capsomeres.
Question 145 of 300
📘 CLASS XI
Biological Classification
Viroids, discovered by T.O. Diener in 1971, are distinct from viruses because they:
Viroids are infectious naked RNA molecules lacking a protein coat.
Question 146 of 300
📘 CLASS XI
Biological Classification
Prions transmit certain severe neurological diseases. Structurally, prions consist of:
Prions are infectious agents composed solely of abnormally folded proteins.
Question 147 of 300
📘 CLASS XI
Biological Classification
Bovine spongiform encephalopathy (BSE) in cattle, commonly known as mad cow disease, is caused by:
Mad cow disease (BSE) is caused by infectious prion proteins.
Question 148 of 300
📘 CLASS XI
Biological Classification
In lichens, what are the roles of the phycobiont and the mycobiont respectively?
The algal partner (phycobiont) prepares food, whereas the fungal partner (mycobiont) provides shelter and absorbs water and minerals.
Question 149 of 300
📘 CLASS XI
Biological Classification
Lichens are considered excellent biological indicators for which of the following?
Lichens are sensitive to air pollution and therefore serve as excellent pollution indicators.
Question 150 of 300
📘 CLASS XI
Biological Classification
Based on R.H. Whittaker's classification, which kingdom contains organisms that have a defined nucleus and membrane-bound organelles, but are strictly single-celled?
Kingdom Protista consists of unicellular eukaryotic organisms with a true nucleus and membrane-bound organelles.