Biotechnology Eligibility Test Preparation

DBT BET JRF Exam: Previous Year Question Paper With Answer Key and Explanations: BET 2012 – 2013 Part 1


What is immunoglobulin domain

(Image 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 1 (Questions 001 – 025)


1. The immunoglobulin fold is made up of:

a.       Seven alpha helical segments
b.      A beta barrel
c.       A sandwich of two parallel beta sheets
d.      A sandwich of two antiparallel beta sheets

Ans. (d). A sandwich of two antiparallel beta sheets

Immunoglobulin fold consists of a pair of β-sheets each built of antiparallel β-strands connected by a disulfide bridge. This β strands surrounds a central hydrophobic core. Immunoglobulin fold is one of the most predominant domains encoded by the human genome.

For more details refer: Biochemistry by Stryer, Ed.6, Chapter: 33, Immune systems, Page 951


2. RNA is analyzed for the location of hairpin folds. Which of the following sequence could form a mini-hairpin?

a.       AGGUUUCCU
b.      AAAAAAAAA
c.       AGGUUUGGA
d.      AGGUUUAGG

Ans. (a). AGGUUUCCU

This RNA molecule can loop around itself and can form double stranded structure due to the sequence complementarity. First A is complementary to last U, second and third nucleotide (UU) is complementary to CC. The middle UUU forms the junction of loop and they do not form the complementary hydrogen bonds.


3. Increasing the concentration of which of the following would most effectively anatomized the inhibition of protein synthesis by puromycin?

a.       ATP
b.      eIF2, GTP
c.       Aminoacyl-tRNAs
d.      Peptidyl-tRNAs

Ans. (c). Aminoacyl-tRNA

Puromycin is an antibiotic obtained from a bacterium Streptomyces alboniger, which inhibit protein synthesis by specifically inhibiting the translation process. Puromycin inhibits protein translation by premature chain termination process. A part of the puromycin structurally mimics the 3’ end of Aminoacyl-tRNA molecule and hence they can enter to the ‘A’ site of ribosome and form a nascent peptide-puromycin adduct. This adducts formation results in the release of peptide from the ribosome. Puromycin compete with aminoacyl-tRNA for the A site of ribosome. Thus the inhibitory effect of puromycin can be theoretically overcome by increasing the concentration of the competitor, i.e., aminoacyl-tRNA.

Continue reading

mcq biology

HSST Botany 2012: Kerala PSC Previous Year Question Paper with Answer Key and Explanations – Part 3

green fluorescent protein

(image source: wikipedia)

Kerala PSC HSST Botany 2012 Examination
Higher Secondary School Teacher: Junior & Senior
Question Paper Code 40/2012 (Cat. NO. 449/2010)

Original question paper of Kerala PSC HSST Botany Junior / Senior (Higher Secondary School Teacher Botany), Category No. 449/2010) examination conducted by Kerala PSC (Public Service Commission) on 13/04/2002 (Q. Code 40/2012) for the appointment of HSST Botany in Government Higher Secondary Schools of Kerala under the Directorate of Higher Secondary Education, Trivandrum, Govt. of Kerala. Questions are in MCQ (Multiple Choice Questions) format.

Part – 3 (Questions 51 – 75)

51.  GFP stands for:

a.       Green Fluorescent Protein
b.      Gene Finger Printing
c.       Grey Fluorescent Protein
d.      Green Fluorescent Plants

Ans. (a). Green Fluorescent Protein

GFP: It is a 26.9 dDa protein with 238 amino acids originally isolated from a jellyfish namely Aequorea victoria. GFP emit green fluorescent light when hit with light waves of ultraviolet region. The excitation wave length of GFP is 395 nm and the emission wavelength is at 475 nm (bright green). GFP is extensively utilized in molecular biology research for tagging biomolecules especially proteins for quantification, localization, interaction of proteins with other proteins or other cellular components. Martin Chalfie, Osamu Shimomura and Roger Y. Tsien were awarded the 2008 Nobel Prize in Chemistry for their discovery and development of the green fluorescent protein. Many variants of GFP are now available each with characteristic excitation and emission ranges.

.

52.  Asafoetida is obtained from which part of Ferula asafetida:

a.       Stem back
b.      Leaf
c.       Root
d.      Fruit

Ans (c). Root

Continue reading

mcq biology

Botany HSST Recruitment: Kerala PSC Question Paper with Answer Key and Explanations: Part 2 (Q 25 – 50)


How is Itty Achutan?

Kerala PSC HSST Botany 2012 Examination
Higher Secondary School Teacher: Junior & Senior
Question Paper Code 40/2012 (Cat. NO. 449/2010)

Original question paper of Kerala PSC HSST Botany Junior / Senior (Higher Secondary School Teacher Botany), Category No. 449/2010) examination conducted by Kerala PSC (Public Service Commission) on 13/04/2002 (Q. Code 40/2012) for the appointment of HSST Botany in Government Higher Secondary Schools of Kerala under the Directorate of Higher Secondary Education, Trivandrum, Govt. of Kerala. Questions are in MCQ (Multiple Choice Questions) format.

Part – 2 (Questions 26 – 50)

26.  Auxospores are produced by:

a.       Volvox
b.      Spirogyra
c.       Diatoms
d.      Oedogonium

Ans. (c). Diatoms

Auxospore is a type of asexual spore in diatoms. Auxopore formation helps the diatomic cells to regain its original cell size which is reduced by repeated mitotic cell divisions. 

27.  Lectins are:

a.       Lipids
b.      Protein binding carbohydrate
c.       Fatty acids
d.      Carbohydrates binding proteins

Ans. (d). Carbohydrates binding proteins

Lectins: they are plant proteins which specifically bind to carbohydrates. They are toxins since they can coagulate glycoproteins. Lectins have immense application in biological research; they can be used for the separation and purification of specific glycoproteins.  In the earlier days, lectins were also used for blood typing. Concanavalin A (ConA) is the first isolated and commercialized plant lectin (isolated from jack bean Canavalia ensiformis). Ricin is another common plant lectin isolated from Ricinus communis (castror).

Continue reading

biological chemistry

Enzyme Regulation Mechanisms: The Molecular Methods to Regulate Enzymes and Enzymatic Acitvity


what are regulatory enzymes

What are enzymes?

Ø  All living organisms in the world should possess TWO fundamental properties

Ø  They are:

(1). Must be able to self-replicate

(2). Must be able to catalyze chemical reactions efficiently and selectively

Ø  Enzymes are the molecules which enables each living entity to do these two fundamental activities

Ø  Enzymes are better known as biological catalysts

Ø  Almost all enzymes are highly specialized proteins

Ø  Ribozymes: RNA molecules with catalytic properties

Ø  Abzymes: antibodies with catalytic properties

What is enzyme regulation?

Ø  Enzyme regulation definition: “Process, by which cells can turn on, turn off, or modulate the activities of various metabolic pathways by regulating the activity of enzyme”

Ø  Enzymes have extraordinary catalytic power

Continue reading

mcq biology

HSST Botany Junior & Senior Kerala PSC Question Paper with Answer Key and Explanations: Part I (Q 1 – 25)


HSST Botany Previous Year Question Papers

Kerala PSC HSST Botany 2012 Examination
Botany Higher Secondary School Teacher: Junior & Senior
Question Paper Code 40/2012 (Cat. NO. 449/2010)

Original question paper of Kerala PSC HSST Botany Junior / Senior (Higher Secondary School Teacher Botany), Category No. 449/2010) examination conducted by Kerala PSC (Public Service Commission) on 13/04/2002 (Q. Code 40/2012) for the appointment of HSST Botany in Government Higher Secondary Schools of Kerala under the Directorate of Higher Secondary Education, Trivandrum, Govt. of Kerala. Questions are in MCQ (Multiple Choice Questions) format.

Part – 1 (Questions 1 – 25)


(1). Key enzyme in PCR:

a.       Taq polymerase
b.      EcoRI
c.       Restriction endonuclease
d.      Ligase

Ans. (a). Taq polymerase

Taq DNA polymerase is a thermostable DNA polymerase enzyme obtained from a thermophilic bacterium Thermus aquaticus. Taq DNA polymerase is frequently used polymerase enzyme in Polymerase Chain Reaction (PCR). The optimum temperature for Taq DNA polymerase is 72oC. Taq DNA polymerase does not have the 3’ – 5’ exonuclease proof reading activity and thus the fidelity of this enzyme is relatively low. Taq DNA polymerase adds a 3’ ‘A’ (adenine) overhang at the 3’ end of PCR products. This property can be used in the ‘TA’ cloning procedure where the PCR products can be easily ligated (cloned) to a vector containing ‘T’ overhangs.

Pfu polymerase is another thermostable DNA polymerase used in PCR, isolated from the bacterium Pyrococcus furiosus. The advantage of using Pfu polymerase over Taq polymerase is that, Pfu polymerase enzyme processes the 3’ – 5’ exonuclease proof reading activity and hence this enzyme shows high fidelity.

EcoRI: restriction enzymes obtained from E. coli.

Restriction enzyme: also called as molecular scissors, are endonuclease enzymes with cut DNA on specific sites, they are important tool in genetic engineering.

Ligase: a class of enzyme which joins two molecules by the formation of new covalent bonds between the two molecules with energy obtained from ATP cleavage. DNA ligase is a type of ligase which catalyzes the formation of phosphodiester bond between two nucleotides.

Continue reading