Q.1. Which of the following is correct about viroids? (2020)
(a) They have DNA with protein coat.
(b) They have free DNA without protein coat.
(c) They have RNA with protein coat.
(d) They have free RNA without protein coat.
Solution. Viroids have free RNA without protein coat. Potato spindle tuber disease is a disease caused by viroids.
Q.2. Which of the following statements is incorrect? (2019)
(a) Yeasts have filamentous bodies with Iong thread-like hyphae.
(b) Morels and truffles are edible delicacies.
(c) Claviceps is a source of many alkaloid and LSD.
(d) Conidia are produced exogenously and ascospores endogenously.
Solution. Yeast is a non-mycelial unicellular ascomycetes fungus. It lacks filamentous structure or hyphae.Yeast Structure
Q.3. Match Column-I with Column-II. (2019)
Choose the correct answer from the options given below:
Solution. Saprophytes: Decomposition of dead organic materials.
Parasites: Grow on/in living plants and animals.
Lichens: Symbiotic association of algae and fungi.
Mycorrhiza: Symbiotic association of fungi with plant roots.
Q.4. Which of the following statements is incorrect? (2019)
(a) Prions consist of abnormally folded proteins.
(b) Viroids lack a protein coat.
(c) Viruses are obligate parasites.
(d) Infective constituent in viruses is the protein coat.
Solution. Infective constituent in viruses is the genetic material, i.e., either DNA or RNA.
Q.5. Match the organisms in column-I with habitats in column-II. (2019)
Select the correct answer from the options given below:
(a) A-(iv), B-(i), C-(iii), D-(ii)
(b) A-(i), B-(ii), C-(iii), D-(iv)
(c) A-(iii), B-(iv), C-(ii), D-(i)
(d) A-(ii), B(iv), C-(iii), D-(i)
Q.6. Which among the following is not a prokaryote? (2018)
Solution. Saccharomyces, i.e., yeast is an eukaryote unicellular fungus. Prokaryotes include bacteria (Mycobacterium), cyanobacteria (Nostoc and Oscillatorica), mycoplasma and archaebacteria.
Q.7. Select the wrong statement. (2018)
(a) Cell wall is present in members of fungi and plantae.
(b) Mushrooms belong to basidiomycetes.
(c) Pseudopodia are locomotory and feeding structures in sporozoans.
(d) Mitochondria are the powerhouse of the cell in all kingdoms except monera.
Q.8. After karyogamy followed by meiosis, spores are produced exogenously in ______. (2018)
Q.9. Oxygen is not produced during photosynthesis by ______. (2018)
(a) Green sulphur bacteria
Solution. Green sulphur bacteria do not have the ability to use water as an electron donor (or cannot oxidise water), instead, they perform photosynthesis using sulfide. Therefore, they do not evolve oxygen during photosynthesis.
Q.10. Which of the following organisms are known as chief producers in the oceans? (2018)
Solution. Diatoms are the most common form of phytoplankton in the ocean. They have the pigment chlorophyll which helps in photosynthesis. Since they are the primary producers of the aquatic chain and the marine ecosystem depends on them. They are called chief producers in the oceans.
Q.11. Ciliates differ from all other protozoans in: (2018)
(a) Using flagella for locomotion.
(b) Having a contractile vacuole for removing excess water.
(c) Using pseudopodia for capturing prey.
(d) Having two types of nuclei.
Solution. Ciliates differ from other protozoans in having two types of nuclei. They are macronucleus and micronucleus (nuclear dimorphism).
Example: Paramecium has a macronucleus which controls metabolic activities as well as growth and a micronucleus that takes part in reproduction.
Q.12. Which of the following are found in extreme saline conditions? (2017)
Solution. Halophiles, a type of archaebacteria, usually occur in extreme saline conditions like salt pans, salt beds and salt marshes.
Q.13. Viroids differ from viruses in having: (2017)
(a) DNA molecules without protein coat
(b) RNA molecules with protein coat
(c) RNA molecules without protein coat
(d) DNA molecules with protein coat
Solution. Viroids are free RNA particles that lack protein coat. They are infectious agents smaller than viruses.
Q.14. Which among the following are the smallest living cells, known without a definite cell wall, pathogenic to plants as well as animals and can survive without oxygen? (2017)
Solution. Mycoplasmas are the smallest living cells, known without a definite cell wall. They are pathogenic to both plants and animals and can survive without oxygen.
Q.15. Which of the following components provides a sticky character to the bacterial cell? (2017)
(a) Nuclear membrane
(b) Plasma membrane
(d) Cell wall
Solution. Glycocalyx is the outermost mucilage layer of the cell envelope which consists of non-cellulosic polysaccharides with or without proteins. It gives a sticky character to the cell.
Q.16. DNA replication in bacteria occurs: (2017)
(a) Within nucleolus
(b) Prior to fission
(c) Just before transcription
(d) During the S phase
Solution. DNA replicates in bacteria just before they divide by fission.
Q.17. Which one of the following is wrong for fungi? (2016)
(a) They are eukaryotic.
(b) All fungi possess a purely cellulosic cell wall.
(c) They are heterotrophic.
(d) They are both unicellular and multicellular.
Solution. The cell wall in fungi is composed of chitin, a polysaccharide comprising N-acetyl-D-glucosamine (a derivative of glucose).
Q.18. Methanogens belong to ______. (2016)
(d) Slime moulds
Q.19. Select the wrong statement. (2016)
(a) The walls of diatoms are easily destructible.
(b) ‘Diatomaceous earth’ is formed by the cell walls of diatoms.
(c) Diatoms are chief producers in the oceans.
(d) Diatoms are microscopic and float passively in water.
Solution. Diatoms are marine or freshwater unicellular organisms that have cell walls (frustules) composed of pectin impregnated with silica and consisting of two halves, one overlapping the other. The siliceous frustules of diatoms do not decay easily.
Q.20. The primitive prokaryotes responsible for the production of biogas from the dung of ruminant animals include the ______. (2016)
Solution. Methanogens are present in the gut of several ruminant animals such as cows and buffaloes and they are responsible for the production of methane (biogas) from the dung of these animals.
Q.21. Which one of the following statements is wrong? (2016)
(a) Eubacteria are also called false bacteria.
(b) Phycomycetes are also called algal fungi.
(c) Cyanobacteria are also called blue-green algae.
(d) Golden algae are also called desmids.
Solution. Eubacteria are also called true bacteria.
Q.22. Which of the following statements is wrong for viroids? (2016)
(a) They cause infections.
(b) Their RNA is of high molecular weight.
(c) They lack a protein coat.
(d) They are smaller than viruses.
Solution. RNA of viroid has a low molecular weight.
Q.23. One of the major components of the cell wall of most fungi is: (2016)
Solution. The fungal cell wall contains chitin or fungal cellulose along with other polysaccharides, proteins, lipids and a number of other substances.
Q.24. Chrysophytes, Euglenoids, Dinoflagellates and Slime moulds are included in the Kingdom ______. (2016)
Solution. Protista is a kingdom of unicellular eukaryotic organisms. It includes photosynthetic protists (dinoflagellates, chrysophytes and euglenoids), consumer-decomposer protists (slime moulds) and protozoan protists.