HBSE Class 12 Biology Question Paper 2021 Answer Key

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HBSE Class 12 Biology Question Paper 2021 Answer Key

Q1. Define  Genotype. 

Ans. The set of genes in our DNA responsible for a particular trait is known as genotype. 


Q2. In  which  of  the  following  polyembryony  is  found  ?   

(A)  Guava   

(B)  Orange 

(C)  Gram 

(D)  Maize 

Ans. (B)  Orange 


Q3. Which  of  the  following  is  sexually  transmitted  disease ? 

(A)  Gonorrhoea 

(B)  Syphilis 

(C)  Hepatitis-B 

(D)  All of these 

Ans. (D)  All of these


Q4. Which  of  the  following  taxa  have  maximum  species  diversity  ? 

(A)  Fishes    

(B)  Reptiles 

(C)  Birds 

(D)  Mammals 

Ans. (A)  Fishes


Q5. The  interaction  between  cattle  egret  and  grazing  cattle  is  an  example  of  : 

(A)  Mutualism   

(B)  Parasitism 

(C)  Commensalism 

(D)  Amensalism 

Ans. (C)  Commensalism 


Q6. In  which  syndrome  a  person  has  47  chromosomes  ? 

(A)  Down’s 

(B)  Klinefelter’s 

(C) both  (A)  and  (B)  

(D)  Turner’s 

Ans. (B)  Klinefelter’s 


Q7. Which  is  a  initiator  Codon  ?  

(A)  AAU  

(B)  AAC 

(C)  AUG  

(D)  AUA 

Ans. (C)  AUG  


Q8. What  is  Barr  Body  ? 

Ans. A Barr body is an inactive X chromosome in a cell with more than one X chromosome. 


Q9. Which  antibodies  are  abundant  in  colostrum  ? 

(A)  IgA   

(B)  IgM

(C)  IgE   

(D)  IgG 

Ans. (A)  IgA   


Q10. Which  RNA  is  called  adaptor  molecule  ?  

(A)  mRNA 

(B)  rRNA 

(C)  tRNA 

(D)  All of these 

Ans. (C)  tRNA 


Q11. When  proinsulin  changes  into  insulin  which  extra  peptide  is  removed  : 

(A)  A   

(B)  B

(C)  C   

(D)  None of these 

Ans. (C)  C   


Q12. What  is  Coleoptile  ? 

Ans. Coleoptile are cylindrical organs that ensheath the first leaf and shoot apex in grass seedings. 


Q13. Write  full  form  of  “Ori”. 

Ans. Origin of Replication


Q14. What  is  insertional  inactivation.  

Ans. insertional inactivation is a technique used in recombinant DNA engineering where a plasmid is used to disable expression of a gene. 


Q15. Name  the  enzyme  used  to  breakdown  cell  wall  of  plant  cell. 

Ans. Cellulase 


Q16. What  are  cytokine  barriers  ? 

Ans. Cytokine barriers are a form of innate immunity that plays an important role in preventing viral replication and responds to many types of antigens and not just one specific. 


Q17. Name  the  diagnostic  test  for  AIDS. 

Ans. ELISA Test ( Enzyme Linked Immunosorbent Assay) 


Q18. Define  Disease. 

Ans. A disease or medical condition is an unhealthy state where something bad happens to the body or mind. 


Q19. What  are  sacred  groves  ? 

Ans. The sacred groves are the trees which are considered as socially, culturally, medicinally or religiously important. Ex – Ficus Religious (Peepal) tree. 


Q20. What  are  stenothermal  organisms  ? 

Ans. The organisms which can tolerate only a narrow range of temperature are called stenothermal organisms. Ex – fishes, corals, snail etc. 


Q21. Define  reproductive  health  according  to  W.H.O. 

Ans. Reproductive health is a state of complete physical, mental and social well-being and not merely the absense of disease or infirmity in all matters relating to the reproductive system and to its functions and processes. 


Q22. Write  down  full  form  of  P.C.R. 

Ans. Polymerase Chain Reaction 


Q23. Which  flower  is  a  good  example  to  study  inheritance  of  flower  colour  in incomplete  dominance  ? 

Ans. Antirrhinum (dog flower) 


Q24. What  is  passive  immunity  ? 

Ans. Passive immunity is the transfer of active humoral immunity of ready-made antibodies. 


Q25. What  is  mutagen  ? 

Ans. Mutagens are the agents that damage our genetic material, usually DNA and results in genetic abnormalities – either inherited or non-inheritrd.


Q26. What  is  Capping  ? 

Ans. It a characteristic of mRNA 


Q27. Which  microbe  is  used  for  commercial  production  of  citric  acid  ? 

Ans. Aspergillus Niger 


Q28. Name  the  bacteria  which  can  fix  atmospheric  nitrogen  while  free  living  in  the soil. 

Ans. Cyanobacteria 


Q29. Alexander  Fleming  was  working  on  which  bacteria  when  he  discovered Penicillin  ? 

Ans. Staphylococci aureus bacteria later identified as Penicillium notatum. 


Q30. What  is  flocs  ? 

Ans. A lossely clumped mass of fine particles. 


Q31. What  is  Palindrome  in  DNA  ? 

Ans. A Palindrome sequence is a sequence made up of nucleic acids within double helix of DNA or RNA that is the same when read from 5′ to 3′ on one strand and 5′ to 3′ on the other complementary strand. 


Q32. Name  the  scientific  name  of  fruit  fly. 

Ans. Drosophila melanogaster 


Q33. The  polypeptide  chains  of  insulin  are  linked  by  which  bonds  ? 

Ans. Disulfide bonds 


Q34. ELISA  is  based  on  which  principle  ? 

Ans. ELISA is based on the principle of antigen – antibody interaction. 


Q35. What  is  Gene  Therapy  ? 

Ans. Gene Therapy is a medical field which focuses on the utilization of the therapeutic delivery of nucleic acids into a patient’s cells as a drug to treat disease . 


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