Assertion (A): Cuscuta is placed in Kingdom Plantae but acts as a parasite.
Reason (R): All plant cells lack a cell wall and prominent chloroplasts.
Cuscuta is a parasitic plant. Plant cells possess a cellulose cell wall and chloroplasts (except in specialized parasitic tissues), therefore the Reason is false.
Question 242 of 300
📘 CLASS XI
Assertion (A): The life cycle of plants exhibits a phenomenon called alternation of generations.
Reason (R): Plants alternate between a diploid sporophytic phase and a haploid gametophytic phase.
Alternation of generations is defined by the alternation between diploid sporophyte and haploid gametophyte generations.
Question 243 of 300
📘 CLASS XI
Assertion (A): Organisms in Kingdom Animalia store their food reserves as glycogen or fat.
Reason (R): Animal cells lack cell walls and possess a holozoic mode of nutrition.
Both are characteristics of Kingdom Animalia, but the absence of a cell wall and holozoic nutrition do not explain why food is stored as glycogen or fat.
Question 244 of 300
📘 CLASS XI
Assertion (A): Viruses were not placed in Whittaker's five kingdom classification.
Reason (R): Viruses are not considered truly living because they lack a cellular structure.
Viruses are acellular and therefore were excluded from Whittaker's classification of cellular organisms.
Question 245 of 300
📘 CLASS XI
Assertion (A): A virus can contain both RNA and DNA simultaneously.
Reason (R): Viruses are obligate parasites that take over the host cell machinery.
No virus contains both RNA and DNA. Viruses are obligate intracellular parasites that utilize host machinery for replication.
Question 246 of 300
📘 CLASS XI
Assertion (A): The protein coat of a virus is called a capsid and is made of capsomeres.
Reason (R): The capsid protects the infectious nucleic acid material of the virus.
The capsid is composed of capsomeres and protects the viral nucleic acid.
Question 247 of 300
📘 CLASS XI
Assertion (A): Bacteriophages are usually double stranded DNA viruses.
Reason (R): Bacteriophages are viruses that specifically infect animals.
Bacteriophages infect bacteria, not animals, and are usually double-stranded DNA viruses.
Question 248 of 300
📘 CLASS XI
Assertion (A): Viroids are distinct from viruses because they lack a protein coat.
Reason (R): Viroids consist of free RNA of low molecular weight.
Viroids are infectious free RNA molecules lacking a protein coat, which distinguishes them from viruses.
Question 249 of 300
📘 CLASS XI
Assertion (A): Prions are infectious agents responsible for causing mad cow disease (BSE).
Reason (R): Prions consist of abnormally folded protein and are similar in size to viruses.
Both statements are correct, but the structural description of prions does not directly explain why they cause BSE.
Question 250 of 300
📘 CLASS XI
Assertion (A): Lichens are considered very good indicators of environmental pollution.
Reason (R): Lichens are highly sensitive to pollution and do not grow in polluted areas.
Lichens are absent from polluted areas due to their high sensitivity to pollutants, making them excellent bioindicators.
