Biotechnology Eligibility Test Preparation

DBT BET Previous Year Question Paper: 2012-2013 with Answer key: Part 4 (Question 101 – 150)


Telomer-structure

Three-dimensional structure of a telomere G-quadruplex (source wikipeida)

Biotechnology Eligibility Test (BET) for DBT JRF Award (2012-13)
Previous Year Question Papers with Answer Key, Explanations & References
Government of India, Ministry of Science & Technology
Department of Biotechnology, New Delhi
PART: B Set 4 (Questions 101– 150)


101. Telomeres consists of simple sequence repeats of

a. CATT rich strands that interact with protein
b. GCCT rich strands that interact with protein
c. CTTT rich strands that interact with protein
d. TTAGGG rich strands that interact with protein

Ans. (a)

Telomere is the sequence occurs at the end of chromosome. Telomere helps to maintain the integrity of chromosome by preventing the end to end fusion of different chromosome and deterioration of chromosomes by nucleases. In vertebrates telomere consists of TTAGGG sequence repeats (~2500 repeats).

102. True activators of transcription are transcription factors that binds to

a. Other proteins to enhance transcription
b. Promoters
c. Enhancers
d. Promoters and enhancers

Ans. (c)

Enhancers are cis acting transcription factor binding sites of DNA (50 – 1500 bp long) of specific genes

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Biotechnology Eligibility Test Preparation

DBT BET Previous Year Question Paper: 2012-2013 with Answer Key: Part 3 (Questions 51-100)


PLoSBiol3.5.Fig7ChromosomesAluFish

Alu sequence in Human Chromosomes (green fluorescence) Source Wikipedia

Biotechnology Eligibility Test (BET) for DBT JRF Award (2012-13)
Previous Year Question Papers with Answer Key, Explanations & References
Government of India, Ministry of Science & Technology
Department of Biotechnology, New Delhi

 PART: B Set 3 (Questions 51 – 100)


51. Suppressor tRNA mutations are those in which

a.       Transcription of tRNA genes is suppressed
b.      Translation form mRNA is suppressed due to absence of tRNA
c.       Amino acid is incorporated in place of a stop codon due to mutation in anticodon region of tRNA
d.      Charging of tRNA with cognate amino acids is suppressed due to mutation in amino acyl tRNA synthase enzyme

Ans. (c)

Suppressor tRNA: also called as nonsense suppressor, due to the suppressor tRNA mutations, an amino acid is incorporated into the stop codon due to mutation in the anticodons of tRNA so that the releasing factors of translation cannot binds to the complex and the translocation process continues.

52. Which of the following media is best suited for the selective growth of E. coli with genotype: Str+ His- leu- lys-?

a.       Minimal medium with thiamine, histidine, leucine and lysine
b.      Luria agar
c.       Minimal medium with thiamine and streptomycin
d.      Minimal medium with thiamine, histidine, leucine, lysine and streptomycin

Ans. (d)

Minimal medium: media that contains minimum nutrients possible for bacterial growth, usually without the presence of amino acids. They used by microbiologists and geneticists to grow “wild type” microorganisms and to select microbes against recombinants.

In the question, the given bacterium is mutated for Histidine, Leucine, and lysine and it has got an antibiotic resistant gene Str+.

53. Which of the following amino acid is coded by maximum number of codons?

a.       Leucine
b.      Tryptophan
c.       Valine
d.      Alanine

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Biotechnology Eligibility Test Preparation

DBT BET JRF Exam 2012-13 Previous Year Question Paper With Answer Key and Explanations Part 2


What are microsatellites?

DNA samples from specimens of Littorina plena amplified using PCR with primers targeting a variable simple sequence repeat (SSR, a.k.a. microsatellite) locus, run on a 5% polyacrylamide gel, visualized by silver staining (source wikipedia)

Biotechnology Eligibility Test (BET) for DBT JRF Award (2012-13)
Previous Year Question Papers with Answer Key, Explanations & References
Government of India, Ministry of Science & Technology
Department of Biotechnology, New Delhi

PART: A Set 2 (Questions 26 – 50)

26.  Which one of the following is the natural host for pseudo-rabies virus?

a.      Dog
b.      Man
c.       Swine
d.      Horse

Ans. (c). Swine

Pseudorabies (Aujeszky’s disease) is a viral disease of swine caused by Suid herpesvirus 1 (SuHV1) belongs to the family Herpesviridae. Other species such as sheep, cattle, and human are also susceptible to SuHV1. This disease is nothing to do with rabies virus. The notorious Rabies virus belongs to the family Rhabdoviridae which cause rabies in human and animals.

27.  Which one of the following is the causative agent of fowl cholera?

a.       V. cholera
b.       P. multocida
c.       E. coli
d.       S. pullorum

Ans. (b). P. multicida

Fowl cholera or avian cholera is caused by Pasteurella multocida. Fowl cholera is considered as Zoonoses

Zoonoses: an infectious disease of animals that can be transferred to human, Example: Rabies

S. pullorum is a poultry adapted species of Salmonella

28.  The wavelengths of light that penetrate the least into the ocean are

a.       Red and violet
b.      Red and yellow
c.       Blue and brown
d.      Green and blue

Ans. (b). Red and Yellow

Yellow, orange and red waves have the least energy in the visible spectrum, thus they cannot penetrated deep into the sea. This is the reason why most of the deep sea animals (fishes) are red in colour. In the deep sea, due to absence of enough light the red colour appears as black so that these animals can be escaped from their predators.

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