Biology Chapter 2 Cell Biology Questions and Answers

Cell Biology 1. Define a gene A gene is a segment of DNA, that can code for a specific protein. Genetic information are stored in DNA. 2. What is a satellite? Certain chromosomes have a rounded body separated from the rest of the chromosome by a secondary construction called satellite. 3. Distinguish autosome from allosome. S.No. 1. 2. 4. Autosome Autosome are somatic chromosomes, controlling body characters. They have no role in sex determination Allosome Allosome are sex chromosomes or accessory chromosomes They play an important role in sex determination What are polytene chromosomes? Polytene chromosomes are sites of increased gene expression for the purpose of secreting specific proteins needed by the larva. 5. What is recon? The smallest unit of DNA capable of recombination is called recon. 6. What is a genome? A complete set of chromosomes containing all the genes is called a genome. 7. What are the two types of nucleic acids? (i) DNA - Deoxyribonucleic acid (ii) R.N.A. - Ribonucleic acid 8. State Chargaff’s rule. The total number of purine molecules in DNA equals that of pyrimidine. (i.e.) (A + G =C+T) 9. What are the different types of R.N.N.? (i) Messenger RNA (mRNA) (ii) Transfer RNA (tRNA) (iii) Ribosomal RNA (rRNA) 10. Define "Transcription". The process by which an enzyme system converts the genetic information of a segment of DNA into an RNA strand, with a base sequence complementary to one of the DNA strands is called as transcription. 11. Define "Translation". The process of tRNA molecules translating the nucleotide sequence of an mRNA into the aminoacid sequence of a Polypeptide is called translation. 12. What are house keeping genes? Some gene products are required all the time and their genes are expressed constantly. These genes are called as house keeping genes. 13. What is constitutive gene expression? Unregulated expression of a gene is called constitutive gene expression. 14. Define "Chromosome mutation". The structural changes occurring in chromosomes which affect the phenotype of the organism are called chromosomal mutations. 15. What is base Analogues? Analogue is a substance that corresponds to the normal DNA base in several characteristics. Because of this the normal base may be replaced by the analogue. 16. What is induced mutation? The mutations that are artificially induced by using physical or chemical agents are called induced mutations. 17. What are mutagenic agents? Physical or chemical agents that can induce mutations are called mutagenic agents, (e.g) U-V rays, phenol, mustard gas. 18. Write the significance of Mutation. (i) The process of speciation to form new species, (ii) Desirable traits are induced in plants and animals (iii) Responsible for evolution 19. Name the institutes in India to improve Mutation breeding. (i) Gamma Garden of Bose Research Institute, Calcutta in 1959 (ii) IARI in New Delhi in 1960 . 20. What is vehicle DNA? DNA molecules which carry foreign DNA inserted into them are called as vectors or vehicle DNA (eg). Bacteriophage, cosmic, plasmid. 21. Mention the advantage employing E.Coli in Biotechnology. (i) (ii) (iii) (iv) 22. What are the advantages in Bacillum subtillis to employ in Industry? (i) (ii) (iii) 23. It can grow at elevated temperature. It has high specific growth rate. Useful in the production of enzymes such as proteases and amylases. Write any two uses of Biosensor. (i) (ii) 24. E.Coli can be easily genetically manipulated or modified It has a well defined genetic system. It has fast growth rate. It is capable of producing desired products economically in a short period. Used in the detection of blood glucose and in Production of any toxin in body due to infection. What are biochips? Biochips are the microcopies developed employing techniques of Biotechnology. Computes can be developed using Biochips.