done 12th Biology Molecular basis of inheritance

• question_answer1)
  Group the following as nitrogenous bases and nucleosides: Adenine, Cytidine, Thymine, Guanosine, Uracil and Cytosine. 
  View Answer play_arrow

• question_answer2)
  If the double stranded DNA has 20% cytosine, calculate the percent of adenine in DNA. 
  View Answer play_arrow

• question_answer3)
  If the sequence of one strand of DNA is written as follows: 5' ATGC ATGC ATGC ATGC ATGC ATGC ATGC 3' Write down, the sequence of complementary strand in direction.  
  View Answer play_arrow

• question_answer4)
  If the sequence of coding strand in transcription unit is written as follows: 5' ATGC ATGC ATGC ATGC ATGC ATGC ATGC 3' write down the sequence of mRNA  
  View Answer play_arrow

• question_answer5)
  Which property of DNA helix led Watson and Crick to hypothesize semiconservative mode of DNA replication. Explain. 
  View Answer play_arrow

• question_answer6)
  Depending upon chemical nature of template (DNA or RNA) and the nature of nucleic acids synthesized from it (DNA or RNA), list the types of nucleic acid polymerases. 
  View Answer play_arrow

• question_answer7)
  How did Hershey and Chase differentiate between DNA and protein in their experiment, while proving DNA is the genetic material? 
  View Answer play_arrow

• question_answer8)
  Differentiate between the following : (a) Repetitive DNA and Satellite DNA (b) mRNA and tRNA (c) Template strand and coding strand  
  View Answer play_arrow

• question_answer9)
  List two essential roles of ribosome during translation. 
  View Answer play_arrow

• question_answer10)
  In medium where E. coli was growing lactose was added, which induced the lac-operon. But why does lac-operon shut down after sometime after addition of lactose in the medium? 
  View Answer play_arrow

• question_answer11)
  Explain (in one or two lines) the function of the following: (a) Promoter (b) tRNA (c) Exons  
  View Answer play_arrow

• question_answer12)
  Why is the Human Genome project called a mega project? 
  View Answer play_arrow

• question_answer13)
  What is DNA finger printing? Mention is applications. 
  View Answer play_arrow

• question_answer14)
  Briefly describe the following : (a) Transcription (b) Polymorphism (c) Translation (d) Bioinformatics  
  View Answer play_arrow

• question_answer15)     In a DNA strand the nucleotides are linked together by (a) glycosidic bonds                                                         (b) phosphodiester bonds (c) peptide bonds                                                            (d) hydrogen bonds

  View Answer play_arrow

• question_answer16)   A nucleoside differs from a nucleotide. It lacks the (a) base                                                (b) sugar                              (c) phosphate group      (d) hydroxyl group

  View Answer play_arrow

• question_answer17)   Both deoxyribose and ribose belong to a class of sugars called (a) trioses                            (b) hexoses                                        (c) pentoses                       (d) polysaccharides

  View Answer play_arrow

• question_answer18)     The fact that a purine always paired base through hydrogen bonds with apyrimidine base leads to, in the DNA double helix (a) the antiparallel nature                                            (b) the semi conservative nature (c) uniform width throughout DNA                          (d) uniform length in all DNA

  View Answer play_arrow

• question_answer19)   The net electric charge on DNA and histories is (a) both positive                 (b) both negative          (c) Both (a) and (b)             (d) zero

  View Answer play_arrow

• question_answer20)   The promoter site and the terminator site for transcription are located at (a) 3' (downstream) end and 5' (upstream) end, respectively of the transcription unit (b) 5' (upstream) end and 3' (downstream) end, respectively of the transcription unit (c) the 5' (upstream) end (d) the 3' (downstream) end

  View Answer play_arrow

• question_answer21)   Which of the following statements is the most appropriate for sickle-cell anaemia? (a) It cannot be treated with iron supplements (b) It is a molecular disease (c) It confers resistance to acquiring malaria (d) All of the above

  View Answer play_arrow

• question_answer22)   One of the following is true with respect to AUG (a) it codes for methionine only (b) it is also an initiation codon (c)it codes for methionine in both prokaryotes and eukaryotes (d) All of the above

  View Answer play_arrow

• question_answer23)   The first genetic material could be (a) protein                          (b) carbohydrates            (c) DNA                                (d) RNA

  View Answer play_arrow

• question_answer24)   With regard to mature mRNA in eukaryotes (a) exons and introns do not appear in the mature RNA (b) exons appear but introns do not appear in the mature RNA (c) introns appear but exons do not appear in the mature RNA (d) both exons and introns appear in the mature RNA

  View Answer play_arrow

• question_answer25)   The human chromosome with the highest and least number of genes in them are respectively (a) chromosome 21 and Y                                             (b) chromosome 1 and X (c) chromosome 1 and Y                                               (d) chromosome X and Y

  View Answer play_arrow

• question_answer26)   Who amongst the following scientists had no contribution in the development of the double helix model for the structure of DNA? (a) Rosalind Franklin       (b) Maurice Wilkins         (c) Erwin Chargaff                            (d) Meselson and Stahl

  View Answer play_arrow

• question_answer27)   DNA is a polymer of nucleotides which are linked to each other by 3'-5'phosphodiester bond. To prevent polymerization of nucleotides, which of the following modifications would you choose? (a) Replace purine with pyrimindines (b) Remove/Replace 3' OH group in deoxy ribose (c) Remove/Replace 2' OH group with some other group in deoxy ribose (d) Both (b) and (c)

  View Answer play_arrow

• question_answer28)   Discontinuous synthesis of DNA occurs in one strand, because (a) DNA molecule being synthesized is very long (b) DMA dependent DNA polymerase catalyze? Polymerization only in one direction (5' 3') (c) it is a more efficient process (d) DNA ligase has to have a role  

  View Answer play_arrow

• question_answer29)   Which of the following steps in transcription is catalyzed by RNA polymerse? (a) Initiation                       (b) Elongation                    (c) Termination                 (d) All of these

  View Answer play_arrow

• question_answer30)   Control of gene expression takes place at the level of (a) DNA-replication         (b) transcription               (c) translation                    (d) None of these

  View Answer play_arrow

• question_answer31)   Regulatory proteins are the accessory proteins that interact with RNA polymerase and affect its role in transcription. Which of the following statements is correct about regulatory protein? (a) They only increase expression (b) They only decrease expression (c) They interact with RNA polymerase but do not affect the expression (d) They can act both as activators and as repressers

  View Answer play_arrow

• question_answer32)   Which was the last human chromosome to be completely sequenced? (a) Chromosome 1          (b) Chromosome 11        (c) Chromosome 21        (d) Chromosome-X

  View Answer play_arrow

• question_answer33)       Which of the following are the functions of RNA? (a) It is carrier of genetic information from DNA to ribosomes synthesizing polypeptides (b) It carries amino acids to ribosomes (c) It is a constituent component of ribosomes (d) All of the above

  View Answer play_arrow

• question_answer34)   While analyzing the DNA of an organism a total number of 5386nucleotides were found out of which the proportion of different bases were Adenine = 29%, Guanine = 17%, Cytosine = 32%, Thymine = 17%. Considering the Chargaffs rule it can be concluded that (a) it is a double-stranded circular DNA                  (b) it is single-stranded DNA (c) it is a double-stranded linear DNA                      (d) No conclusion can be drawn

  View Answer play_arrow

• question_answer35)   In some viruses, DNA is synthesized, be using RNA as template. Such a DNA is called (a) A-DNA                           (b) B-DNA                           (c) c-DNA                             (d) r-DNA

  View Answer play_arrow

• question_answer36)   If Meselson and Stahl's experiment is continued for four generations in bacteria, the ratio of /:/:/, containing DNAin the fourth generation would be (a) 1:1:0                (b) 1:4:0               (c) 0:1:3                (d) 0:1:7

  View Answer play_arrow

• question_answer37)     If the sequence of nitrogen bases of the coding strand of DNA in a transcription unit is5'- A T G A A T G - 3',the sequence of bases in its RNA transcript would be (a) 5' - A U G A A U G - 3'                                               (b) 5' - U A C U U A C - 3' (c) 5' - C A U U C A U - 3'                                                (d) 5' - G U A A G U A - 3'

  View Answer play_arrow

• question_answer38)   The RNA polymerase holoenzyme transcribes (a) the promoter, structural gene and the terminator region (b) the promoter and the terminator region (c) the structural gene and the terminator regions (d) the structural gene only

  View Answer play_arrow

• question_answer39)     If the base sequence of a codon in mRNA is 5'-AUG-3', the sequence oftRNA pairing with it must be (a) 5' - UAC - 3'                  (b) 5' - CAU - 3'                  (c)5'-AUG-3'                       (d) 5' - GUA - 3'

  View Answer play_arrow

• question_answer40)       The amino acid attaches to the tRNA at its (a) 5'-end                            (b) 3'-end                            (c) Anti codon site           (d) DHU loop

  View Answer play_arrow

• question_answer41)   To initiate translation, the mRNA first binds to (a) the smaller ribosomal sub-unit                            (b) the larger ribosomal sub-unit (c) the whole ribosome                                                 (d) No such specificity exists

  View Answer play_arrow

• question_answer42)   In E. coli, the lac operon gets switched on when      (a) lactose is present and it binds to there pressor (b) repressor binds to operator (c) RNA polymerase binds to the operator (d) lactose is present and it binds to RNA polymerase

  View Answer play_arrow

• question_answer43)   What is the function of his tones in DNA packaging?

  View Answer play_arrow

• question_answer44)   Distinguish between heterochromatin and euchromatin. Which of the two is transcriptionally active?

  View Answer play_arrow

• question_answer45)   The enzyme DNA polymerase in E.coli is a DNA dependent polymerase and also has the ability to proofread the DNA strand being synthesized Explain. Discuss the dual polymerase.

  View Answer play_arrow

• question_answer46)   What is the cause of discontinuous synthesis of DNA on one of the parental strands of DNA? What happens to these short stretches of synthesized DNA?

  View Answer play_arrow

• question_answer47)   Given below is the sequence of coding strandof DNA in a transcriptionunit 3' AATGCAGCTAT TAGG-5' write the sequence of (a) its complementary strand (b) the mRNA

  View Answer play_arrow

• question_answer48)   What is DNA polymorphism? What is it important to study it?

  View Answer play_arrow

• question_answer49)   Based on your understanding of genetic code, explain the formation of any abnormal haemoglobin molecule. What are the known consequences of such a change?

  View Answer play_arrow

• question_answer50)   Sometimes cattle or even human beings give birth to their young ones that are having extremely different sets-of organs like limbs/position ofeye(s) etc. Comment.

  View Answer play_arrow

• question_answer51)   In a nucleus, the number of rib nucleoside triphosphates is 10 times the number of deoxy x 10 ribonucleoside triphosphates, but only deoxyribonucleotides are added during the DNA replication. Suggest a mechanism.

  View Answer play_arrow

• question_answer52)   Name a few enzymes involved in DNA replication other than DNApolymerase and ligase. Name the key functions for each of them.

  View Answer play_arrow

• question_answer53)   Name any three viruses which have RNA as the genetic material.

  View Answer play_arrow

• question_answer54)   Define transformation in Griffith's experiment. Discuss how it helps in the identification of DNA as the genetic material.

  View Answer play_arrow

• question_answer55)   Who revealed biochemical nature of the transforming principle?

  View Answer play_arrow

• question_answer56)   Discuss the significance of heavy isotope of nitrogen in the Meselson and Stahl?s experiment.

  View Answer play_arrow

• question_answer57)   Define a cistron Giving examples differentiate between monocistronic and polycistronic unit.

  View Answer play_arrow

• question_answer58)   Give any six features of the human genome.

  View Answer play_arrow

• question_answer59)   During DNA replication, why is it that the entire molecule does not open in one go? Explain replication fork. What are the two functions that the monomers (dNTPs) play?

  View Answer play_arrow

• question_answer60)   Retroviruses do not follow central dogma. Comment.

  View Answer play_arrow

• question_answer61)   In an experiment, DNA is treated with the compound which tends to place itself amongst the stacks of nitrogenous base pairs. As a result of this, the distance between two consecutive base increases. From 0.34-0.44nmcalculate the length of DNA double helix (which has 2 x 109 bp) in the presence of saturating of this compound.

  View Answer play_arrow

• question_answer62)   What would happen if histones were to be mutated and made rich in acidic amino acids such as aspartic acid and glutamic acid in place of basic amino acids such as lysine and arginine?

  View Answer play_arrow

• question_answer63)   Recall the experiments done by Frederick Griffith, Avery, MacLeod and McCarty, where DNA was speculated to be the genetic material. If RNA ,instead of DNA was the genetic material, would the heat killed strain of Pneumococcus have transformed the R-strain into virulent strain? Explain.

  View Answer play_arrow

• question_answer64)   You are repeating the Hershey-Chase experiment and are provided with two isotopes32P and15N (in place of 35S in the original experiment). How does you expect your results to be different?

  View Answer play_arrow

• question_answer65)   There is only one possible sequence of amino acids when deduced from agiven nucleotides. But multiple nucleotides sequence can be deduced from a single amino acid sequence. Explain this phenomena.

  View Answer play_arrow

• question_answer66)   A single base mutation in a gene may not 'always' result in loss or gain of function. Do you think the statement is correct? Defined your answer.

  View Answer play_arrow

• question_answer67)   A low level of expression of lac operon occurs at all the time. Can you explain the logic behind this phenomena.

  View Answer play_arrow

• question_answer68)   How has the sequencing of human genome opened new windows for treatment of various genetic disorders. Discuss amongst your classmates.

  View Answer play_arrow

• question_answer69)   The total number of genes in humans is far less (<25000) than the previous estimate (up to 140000 gene). Comment.

  View Answer play_arrow

• question_answer70)   Now, sequencing of total genomes is getting less expensive day by day. Soon it may be affordable for a common man to get his genome sequenced. What in your opinion could be the advantage and disadvantage of this development?

  View Answer play_arrow

• question_answer71)   Would it be appropriate to use DNA probes such as VNTR in DNA fingerprinting of a bacteriophage?

  View Answer play_arrow

• question_answer72)   During in vitro synthesis of DNA, a researcher used 2', 3'-dideoxy cytidinetriphosphate as raw nucleotide in place of 2'-deoxy cytidine. What would be the consequence?

  View Answer play_arrow

• question_answer73)   That background information did Watson and Crick have made available for developing a model of DNA? What was their contribution?

  View Answer play_arrow

• question_answer74)   What are the functions of (i) methylated guanine cap? (ii) poly-A 'tail' in a mature on RNA?

  View Answer play_arrow

• question_answer75)   Do you think that the alternate splicing of exons may enable a structural gene to code for several is proteins from one and the same gene? If yes how? If not, why so?

  View Answer play_arrow

• question_answer76)   Comment on the utility of variability in number of tandem repeats during DNA fingerprinting.

  View Answer play_arrow

• question_answer77)   Give an account of Hershey and Chase experiment. What did it conclusively prove? If both DNA and proteins contained phosphorus and sulphur do you think the result would have been the same?

  View Answer play_arrow

• question_answer78)   During the course of evolution why DNA was chosen over RNA as genetic material. Give reasons by first discussing the desired criteria in a molecule that can act as genetic material and in the light of biochemical differences between DNA and RNA.

  View Answer play_arrow

• question_answer79)   Give an account of post transcriptional modifications of a eukaryoticm RNA.

  View Answer play_arrow

• question_answer80)   Discuss the process of translation in detail.  

  View Answer play_arrow

• question_answer81)     Define an operon, giving an example, explain an inducible operon.

  View Answer play_arrow

• question_answer82)   'There is a paternity dispute for a child'. Which technique can solve the problem? Discuss the principle involved.

  View Answer play_arrow

• question_answer83)     Give an account of the methods used in sequencing the human genome.

  View Answer play_arrow

• question_answer84)   List the various markers that are used in DNA fingerprinting.

  View Answer play_arrow

• question_answer85)   Replication was allowed to take place in the presence of radioactive eoxynucleotides precursors in E.coli that was a mutant for DNA ligase. Newly synthesized radioactive DNA was purified and strands were separated by denaturation. These were centrifuged using density gradient centrifugation. Which of the following would be a correct result?   (a) (b)     (c)   (d)  

  View Answer play_arrow