64. Which kingdom principally includes unicellular eukaryotic organisms?
[RPSC Examination, 2015]
(A) Monera
(B) Protista
(C) Fungi
(D) All three kingdoms
Answer: (B) Protista
Explanation: Protista contains many single-celled eukaryotes, including protozoans and numerous unicellular algae. Monera comprises prokaryotes, while most fungi are filamentous multicellular organisms, with yeast as an exception.
63. Which pairing of an organism with its fungal classification is correct?
[AIPMT, 2015]
(A) Agaricus-parasitic basidiomycete
(B) Phytophthora-basidiomycete
(C) Alternaria-Deuteromycetes with no known sexual stage
(D) Mucor-Ascomycetes reproducing by conjugation
Answer: (C) Alternaria-Deuteromycetes with no known sexual stage
Explanation: Alternaria was traditionally placed in Deuteromycetes because its sexual stage was not identified. Agaricus is chiefly a saprophytic basidiomycete, while Phytophthora and Mucor belong to different fungus-like or fungal groups.
62. A true membrane-enclosed nucleus is missing in which organism?
[AIPMT, 2015]
(A) Volvox
(B) Anabaena
(C) Mucor
(D) Vaucheria
Answer: (B) Anabaena
Explanation: Anabaena is a filamentous cyanobacterium and therefore prokaryotic. It lacks a nuclear membrane. Volvox and Vaucheria are eukaryotic algae, whereas Mucor is a eukaryotic fungus.
61. Which virus has helical RNA encased in regularly arranged capsomeres?
[AIPMT, 2014]
(A) Tobacco mosaic virus
(B) Measles virus
(C) Retrovirus
(D) Poliovirus
Answer: (A) Tobacco mosaic virus
Explanation: Tobacco mosaic virus has a classic rod-shaped helical capsid surrounding a single-stranded RNA genome. Its uniform capsomeres make it a standard example of helical viral symmetry in biology textbooks.
60. Match the following organisms with their groups: A Ascaris, B malarial parasite, C housefly, D cow; 1 Mammalia, 2 Arthropoda, 3 Nematoda, 4 Protozoa.
[UPSC CDS II, 2014]
(A) A-3, B-4, C-2, D-1
(B) A-3, B-2, C-4, D-1
(C) A-1, B-2, C-4, D-3
(D) A-1, B-4, C-2, D-3
Answer: (A) A-3, B-4, C-2, D-1
Explanation: Ascaris is a nematode roundworm, the malarial parasite Plasmodium is a protozoan protist, the housefly is an arthropod insect, and the cow is a mammal. Hence the matching is 3, 4, 2, 1.
59. Which structure chiefly differentiates archaebacteria from eubacteria?
[AIPMT, 2014]
(A) General nutritional mode
(B) Cell shape
(C) Ordinary division method
(D) Membrane lipid structure
Answer: (D) Membrane lipid structure
Explanation: Archaea have characteristic membrane lipids with ether linkages and branched hydrocarbon chains. Bacteria generally use ester-linked fatty acids. These molecular differences help archaea survive in specialised and sometimes extreme habitats.
58. Which statement about gametes is incorrect?
[NEET UG, 2013]
(A) Isogametes are similar
(B) Anisogametes differ in one or more traits
(C) In oomycetes the female gamete is small and motile while the male is large
(D) Chlamydomonas may show isogamy or anisogamy
Answer: (C) In oomycetes the female gamete is small and motile while the male is large
Explanation: Oogamous reproduction typically has a large non-motile female gamete and a smaller male gamete. The reversed description in the stated option is therefore false. Chlamydomonas displays diverse forms of sexual reproduction.
57. Pigment-bearing membranous extensions in certain cyanobacteria are called:
[NEET UG, 2013]
(A) Heterocysts
(B) Basal bodies
(C) Pneumatophores
(D) Chromatophores
Answer: (D) Chromatophores
Explanation: Chromatophores are membrane-associated structures containing photosynthetic pigments in older descriptions of bacteria and cyanobacteria. Heterocysts specialise in nitrogen fixation, while basal bodies and pneumatophores serve entirely different functions.
56. Which group is especially likely to inhabit extreme deep-sea environments?
[NEET UG, 2013]
(A) Archaebacteria
(B) Ordinary surface-water bacteria
(C) Blue-green algae
(D) Terrestrial saprophytic fungi
Answer: (A) Archaebacteria
Explanation: Many archaea possess metabolic and structural adaptations for high pressure, unusual temperatures or oxygen-poor deep-sea sediments. Photosynthetic cyanobacteria require light, making them less characteristic of great ocean depths.
55. How many are autotrophs: Lactobacillus, Nostoc, Chara, Nitrosomonas, Nitrobacter, Streptomyces, Saccharomyces, Trypanosoma, Porphyra and Wolffia?
[AIPMT Mains, 2012]
(A) Four
(B) Five
(C) Six
(D) Three
Answer: (C) Six
Explanation: Nostoc, Chara, Porphyra and Wolffia are photosynthetic, while Nitrosomonas and Nitrobacter are chemoautotrophic bacteria. The remaining four depend on organic food. The total number of autotrophs is therefore six.
