CBSE biology question paper NEET
1. It deals with identification, nomenclature and classification of organisms.
2. It is the system of phylogenetic classification which is based on affinities, similarities and dissimilarities of characteristics present in the present day of the organism.
3. Carolus Linnaeus is known as the father of taxonomy. He published a number of important books, eg., Genera Plantarum, Species Plantarum etc. and gave binomial nomenclature
4. Cyanophages are viruses infecting blue-green algae.
5. A bacteriophage is a double-stranded DNA containing a virus which infects bacteria
6. Plus is a short filamentous structure composed of protein that extends from the surface of a bacterial cell.
14. When prothallus of a fern, give rise to sporophyte directly from somatic cell without forming gametes then it is called apogamy. Such type of sporophyte is haploid in nature. Development of gametophyte directly from a sporophyte without meiosis and without forming spore is apospory.
15. As one moves from Thallophyta Bryophyta Pteridophyta Gymnosperm Angiosperm, there is a reduction in the gametophyte and elaboration of the sporophyte.
16. Zinc is an activator of enzymes like carbonic anhydrase. Copper takes part in electron transport as plastocyanin Potassium maintains membrane permeability.
18. In the plant, peroxisomes are associated with photorespiration. They are associated with chloroplasts and mitochondria.
19. The thylakoid membranes possess the chlorophylls. The outer membrane is permeable to a number of solutes. Inner membrane has a number of carrier proteins. Stroma forms the matrix containing the enzyme for Calvin cycle.
22. Unlike his predecessors, who simultaneously worked on a large number of characters, Mendel studied the inheritance of a single trait, one at a time.
23. Induced mutation are produced in response to certain external factors or chemicals who are turned as a mutagen.
24. On mating tt with Tt, 50% individual offsprings are recessive and 50% inhibit heterozygotes dominant characteristics.
25. We know that replum in the ovary of the flower of mustard and other members of family Cruciferae. In this family, the ovary is initially bi- carpellary and unilocular but it becomes bilocular due to the formation of replum which is a false septum
26. Transformation involves the uptake of naked DNA molecules from one bacterium (the donor cell) by another bacterium (the recipient cell).
27. A nucleotide is derived from a nucleoside by the addition of a molecule of phosphoric acid.
28. The thallus of every lichen is composed of two quite different organisms, a fungus and an alga. The fungal component forms the bulk of the lichen thallus. The fungal hyphae form a close network resembling a tissue-like mass with the algal cells often embedded in it. Algae synthesise their own food from carbon dioxide and water. Probably food materials from the alga diffuse out and are absorbed by the fungus. The reproductive organs, however, are entirely fungal in character.
29. Mutation provides the raw material for evolution. Recombination merely rearranges this genetic variability into new combinations and natural selection simply preserves the combinations. Without mutations, all genes would exist in only one form. Alleles would not exist, and thus genetic analysis would not be able to evolve and adapt to environmental changes. Mutation then is an important phenomenon.
30. Both carotenes and xanthophylls are soluble in organic solvents like chloroform, ethyl ether, etc. Carotenes are more soluble in carbon disulphide as compared to xanthophylls. Xanthophylls are oxygen-containing derivatives of carotenes. E.g., Cryptoxanthin, lutein and zeaxanthin.
46. Study of pollen grains is called palynology.
47. The aggregate of all the genes and their alleles present in an interbreeding population is known as gene pool.
48. Inducible, repressible.
49. Ozone-depleting substances.
50. It is a modern technique of identifying individuals by comparing nucleotide sequence of their DNA’s.