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

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