DBT JRF STUDY MATERIAL

Transcription

1 DBT JRF STUDY MATERIAL (Sandesh, Urban Pro) 1. The molarity of a 15 % of NaCl solution in water is (A) 2.56 (B) (C) 25.6 (D) How to solve: 15% Nacl means 15g NaCl in 100ml of water i.e. 150g in 1000ml. Molecular wt of NaCl is 58.5 So 58.5 g in 1000ml is 1M, therefore molarity when 150g is dissolved in 1000ml (15%) is 150/58.5=2.56M Answer: A) 2.56M 2. Protein A from Pseudomonas putida contains 135 amino acids. The number of nucleotides present in the gene encoding the protein will be (A) 405 (B) 408 (C) 411 (D) 421 Answer: B) Consider three independently assorting gene pairs, A/a, B/b, and C/c. The probability of obtaining an offspring of AABbCc from parents that are AaBbCC and AABbCc is (A) 4/9 (B) 3/4 (C) 1/8 (D) 1/9 How to solve: If we cross AABbCc with AaBbCC we get following gametes AABbCc * AaBbCC ABC ABc AbC Abc ABC AbC abc abc Now if you cross it, you will get 2 AABbCc genotypes out of 16, so the probability is 2/16 which can be written as 1/8 Answer: C) 1/8

2 4. LDL binds with cell surface receptor and gets internalized via clathrinmediated endocytosis. This process helps in maintaining the cholesterol-ldl level in the plasma. However, in a disease known as familial hypercholesterolemia (FH), very high levels of plasma cholesterol is found. This could be due to mutation in which one of the following genes in FH patients? (A) Clathrin (B) LDL (C) LDL receptor (D) Adaptor Anwer: C) LDL receptor 5. Digestion of a 5Kb linear DNA fragment with EcoRI generates two fragments of 2 Kb and 3 Kb, while digestion of the same molecule with HindIII yields three fragments of 0.7 Kb, 3.5 Kb and 0.8 Kb. When the same DNA is digested with both the enzymes, it yields fragments of 0.7 Kb, 1.3 Kb, 2.2 Kb and 0.8 Kb. The right sequence of restriction sites in the DNA fragment is (A) One EcoRI site in between two HindIII sites (B) One HindIII site in between two EcoRI sites (C) Two HindIII sites followed by only one EcoRI site (D) One EcoRI site followed by two HindIII sites. Answer: A) one EcoR1 site in between two HindIII sites Reason: 5Kb linear DNA fragment EcoR1 2Kb fragment 3Kb fragment Same DNA fragment subjected to Hind III digestion 0.3Kb 3.9Kb 0.8Kb When the same DNA fragment is treated with both E.Coli and Hind III four fragments are produced 0.3Kb,0.8Kb,1.7Kb and 2.2Kb; 0.3Kb and 0.8Kb fragments are produced by Hind III therefore it has two restriction site but E.Coli has one restriction site which is present in the 3.9Kb fragment of Hind III digest, thus the mixture of E.Coli and HindIII produce four fragments.

3 6. Which one of the following side chains of an amino acid is responsible for fluorescence in proteins? (A) Indole ring (B) Guanidino group (C) Phenolic group (D) Imidazole group Answer: A) Indole ring 7. Which one of the following virus is the odd one out? (A) Epstein-Barr Virus (B) Human Immunodeficiency Virus. (C) Human Papilloma Virus (D) Human T-cell leukemia Virus Answer: B) Human Immunodeficiency Virus 8. Which of the following is not specifically protected by intellectual property legislation? (A) Industrial designs. (B) Patents. (C) Trademarks. (D) Trade secrets. Answer: D) Trade secrets 9. In persons suffering from sickle cell anemia, the 6th amino acid of beta globin protein is valine instead of glutamic acid. This has occurred due to substitution mutation leading to a change in glutamic acid codon to valine codon in the gene. The mutation is a (A) transition where a purine base changes to another purine base (B) transition where pyrimidine base changes to another pyrimidine base (C) transversion where pyrimidine base changes to a purine base (D) transversion where purine base changes to a pyrimidine base Answer: D) transversion where purine base changes to a pyrimidine base [ The codon GAG codes for glutamic acid, the mutation involves the change of nucleotide A to T, where T is a pyrimidine base, so the codon will be GTG which codes for Valine. Example for SNP]

4 10. What is glycosuria? (A) Low amount of sugar in urine (B) Low amount of fat in urine (C) Average amount of carbohydrate in urine (D) High amount of sugar in urine Answer: D) High amount of sugar in urine 11. Which of following viruses causes liver cancer? (A) Papilloma virus. (B) Herpes simplex virus. (C) Hepatitis B virus. (D) Hepatitis C virus. Answer: C) Hepatitis C virus 12. Which one of the following methods is frequently used to create transgenic animals? (A) Particle bombardment (B) Nuclear microinjection (C) Nuclear fusion (D) Nucleo-cytoplasmic transplantation Answer: B) Nuclear microinjection 13. Which one of the following is true about epigenetic changes? (A) Changes are caused by deletion and are heritable (B) Changes are caused by mutation and are heritable (C ) Changes are caused by mutation but are not heritable (D) Changes are caused by DNA methylation and are heritable Answer: B) Changes are caused by mutation and are heritable 14. Which one of the following DNA viruses has part of its life cycle involving Reverse Transcriptase enzyme, which is a hallmark of Retroviruses? (A) Epstein-Barr virus (B) Herpes simplex virus (C) Hepatitis B virus (D) Hepatitis C virus Answer: D) Hepatitis C virus 15. H1N1, H1N2, H2N1, H3N1 and H3N2 are subtypes of which influenza virus? (A) Influenza A

5 (B) Influenza B (C) Influenza C (D) Influenza D Answer: A) Influenza A 16. Which of the following enzymes is required to release the tension imposed by uncoiling of strands? (A) Endonuclease (B) DNA helicase (C) Topoisomerase I (D) Topoisomerase II Answer: D) Topoisomerase II 17. DNA fingerprinting is based on (A) (B) (C) (D) Occurence of VNTR s Knowledge of human karyotype Cloned DNA Recombinant DNA Answer: A) Occurence of VNTR s 18. A DNA strand with a sequence 5 CGA TTG3 would be complementary to the sequence (A) 5 GCU AAC3 (B) 5 GCT AAC3 (C) 5 GTT AGC3 (D) 5 CAA TCG3 Answer: D) 5 CAA TCG3 19. Which of the following can be used to demonstrate protein binding to specific DNA sequences (A) Western blot hybridization (B) Northern blot hybridization (C) Electrophoretic mobility shift assay (D) Polymerase Chain Reaction Answer: C) Electrophoretic mobility shift assay

6 20. All of the following serve as intracellular messengers except (A) c AMP (B) Acetylcholine (C) Inositol1,4,5- triphosphate (D) 1,2 Diacyl glycerol Answer: B) Acetylcholine