Practice Test


1) Accroding to current ideas concerning protein synthesis:


2) Transfer RNA is synthesized:


3) DNA is believed to be the genetic material because:


4) In a DNA molecule, the sugars:


5) If replication were conservative, which of the following banding patterns would Meselson and Stahl have found in the fourth generation? (Note: concentration refers to concentration of DNA).


6) Which of the following would not be used in preparing recombinant DNA?


7) Non-sense codons are present in:


8) If a cell is treated with nucleic acid destructing material, which will firstly be prevented?


9) DNA synthesis takes place in:


10) For deciphering the genetic code, H. G. Khorana synthesized:


11) The experimental system used in the studies on the discovery of replication of DNA has been:


12) Acetabularia has been used as an experimental material to prove that:


13) Barr-body seen in saliva test in Olympic games is associated with:


14) RNA- synthesis may be restricted by:


15) X-Ray diffraction technique was used by Wilkins and Franklin to ascertain structure of:


16) The functional genetic unit is:


17) In his experiment on the chemistry of DNA, Chargaff estimated the base composition of human sperms and found that Adenine constituted 31% and Guanine 19%. The quantity of cytosine in the DNA of human somatic cell is likely to be:


18) The base sequence for a nucleic acid segment is given as GAG, AGG, GGA, CCA. From this it can be concluded that it is a segment of a:


19) A DNA strand is directly involved in the synthesis of all the following except:


20) Which one of the following is specific for a amino acid?


21) Which is required for protein synthesis?


22) DNA polymerase is required for the synthesis of:


23) Amino acid is carried by RNA at its:


24) In yeast alanyl-tRNA, the number of nucleotides are:


25) At 3' end t-RNA involved in transfer of amino acids:


26) Replication of DNA in eukaryotes commences from:


27) Streptomycin and related antibiotics bind to small sub-units of ribosomes in prokaryotes and they:


28) Sickle cell anaemia is caused by change in:


29) Heredity is brought about by transference from one generation to another of a substance with definite chemical having specific molecular constitution was mentioned by:


30) Okazaki segments are:


31) Transcription is the process by which:


32) The one aspect which is not a salient feature of genetic code, is its being:


33) One gene-one enzyme hypothesis was given by:


34) Transcription is carried out by:


35) mRNA of eukaryotes is synthesized with the help of:


36) Which of the following is called adapter molecule?


37) DNA replication is aided by:


38) The element required for the activation of DNA and DNA polymerase is:


39) The structure of holoenzyme RNA polymerase include:


40) For studying the metabolism of DNA radioautographic technique is used involving:


41) The recent technique used for separating fragments of DNA is:


42) Technique for detecting and screening the nutritional mutant in Neurospora crassa was developed by:


43) A DNA molecule in which both strands have radioactive thymine is allowed to duplicate in an environment containing non-radioactive thymine. What will be the correct number of DNA molecules that contain same radio-active thymine after three duplications?


44) What is the name of Noble laureates in relation with DNA?


45) If a sperm cell of a mouse contains 1.8 picograms of DNA in the nucleus, the mass of DNA expected in the nucleus of liver cell would be how many picograms:


46) The first amino acid in any polypeptide chain in prokaryotes is always:


47) A polypeptide is produced as dictated by mRNA, the number of bases on the mRNA that code for the polypeptide portion containing N-terminal amino acid and next 13 amino acid is:


48) The transformation experiment conducted by Avery, MacLeod and McCarthy using Diplococcus bacteria proved that:


49) "Degenerate" codes are when:


50) The degeneracy in genetic code was found by:


51) Normally GUG specifies valine amino acid, but when AUG is initiation codon then it specifies which one of the following amino acid?


52) The site of protein synthesis is:


53) The semi-conservative mode of DNA replication was proved by:


54) A sequence of three bases which stands for an amino acid is called:


55) Various metabolic activities of the cell are controlled and directed by:


56) The RNA transporting amino acid to the protein synthesizing site is called:


57) Select the specific base pairs of DNA:


58) mRNA in prokaryotes is:


59) The bits of DNA formed join with each other by an enzyme:


60) Catalytic property of RNA was discovered by:


61) Which is correct sequence according to increasing molecular weight?


62) The two strands of DNA are:


63) The diameter of DNA molecule is:


64) The hydrogen bonds between adenine and guanine are:


65) The approximate life span of m-RNA is:


66) Which one of the following bases is found only in the RNA and not in DNA?


67) RNA controls the synthesis of:


68) A protion of DNA has ACT, CAT, TCA, what would be the sequence of complementary DNA?


69) In Neurospora meiosis takes place:


70) The term heterochromatin was given by:


71) Histones occupy the major grooves of DNA at an angle of:


72) DNA-histone complex can be removed from chromosome by treatment with:


73) There are special protein that help to open up DNA double helix in front of replication fork. These proteins are:


74) If the DNA codons ATG ATG ATG and a cytosine base is inserted at the beginning, which of the following will result?


75) If the sequence of bases in DNA is ATTCGATG, then the sequence of bases in its transcript will be:


76) H. G. Khorana got the Noble Prize on:


77) The transfer of genetic material from one cell to another by a phage is called:


78) Autocatalytic function is shown by:


79) There is no masking of expression of genes in Neurospora because it:


80) In which of the following places, messenger RNA is found in a living cell?


81) The function of a non-sense codon is:


82) Functional unit of DNA which specifies the formation of a single peptide is:


83) A mutant DNA is caused by insertion of extra base to DNA by a mutagen:


84) In Beadle and Tatum's Neurospora experiments. Amino acid needed by mutants were:


85) The single stranded strand of nucleotide between a gene and a polypeptide is:


86) r-RNA is transcribed on DNA template by:


87) The number of polymerase in eukaryotic and prokaryotic cells are:


88) Which of the following is not correct for DNA chain?


89) Wobble position means:


90) The possibility of wrong base introduction during DNA replication is at frequency of:


91) Two strands of DNA are coiled around:


92) DNA duplication occurs in:


93) Which is not required for polypeptide synthesis?


94) Which is the correct sequence of code transfer involved in the formation of a polypeptide?


95) The flow of information from DNA to mRNA is called:


96) Nucleic acids are polymers of:


97) Two strands of DNA are attached by hydrogen bonds between:


98) Z-DNA is:


99) Satellite DNA is present in:


100) Plasmids are:


101) The genetic code is called degenerate code because:


102) Anticodon is present on:


103) The first translated codon in any mRNA is always:


104) The instructions for the synthesis of a protein coat in a cell are always inscribed in the form of a:


105) m-RNA is produced in the:


106) The synthesis of polypeptide chain begins at the:


107) Cracking the genetic code in vitro was largely the work of:


108) The double helix makes a complete turn:


109) Which one of the following pair is correctly matched?


110) Lac-operon is related to:


111) Which site of tRNA molecule hydrogen binds to a mRNA molecule?


112) Which one of the following pair is correctly matched?


113) A gene which synthesizes a repressor protein is:


114) In an operon, the RNA polymerase binds to:


115) Which of the following is a recombinant DNA?


116) Which of the following is empolyed in recombinant DNA technology?


117) Which one of the following units is unrelated to DNA or gene?


118) Genetic engineering would not have been possible if one of these were absent:


119) Which of the following organelles is associated with genetic engineering?


120) In genetic engineering, the cutting DNA segment, which of the enzymes is used?


121) Nobel Prize to A. Kornberg and S. Ochoa was given for:


122) A gene may best be defined according to its:


123) In DNA sugar and phosphate form backbone of the molecule. The adjacent sugars are joined to each other by:


124) Fredrick Sanger of Cambridge, UK won his second Nobel Prize for his work on:


125) Khorana synthesized a biologically functional tyrosine suppressor t-RNA of E. coli in 1979 it contained:


126) The enzyme needed for repairing DNA break and releasing tension caused by rotation of DNA molecule is:


127) When pure DNA was digested by nuclease, DNA fragments of all sizes were obtained. But when chromatin was digested with same enzyme, DNA fragmets of sizes, multiples of a smallest unit size were obtained. This suggests that in the chromatin, histone proteins are associated with DNA all along its length:


128) An antibiotic which inhibits translation in eukaryotes is:


129) Gene controls:


130) Okazaki fragments are seen on:


131) RNA primer is formed over:


132) In Citrulline auxotroph of Neurospora crassa:


133) In general bacterial genes are regulated at the time of:


134) The activity of repressor depends upon whether:


135) Who followed the trail of Griffith's work and proved DNA is the genetic material?


136) Which object did Hershey and Chase (1952) choose to confirm that DNA is the hereditary material?


137) Who was not awarded Nobel Prize alongwith Watson, Crick and Wilkins for an extensive work on the structure of DNA?


138) The function of helix-destabilizing proteins is to:


139) Genes are located in a linear-fashion on the:


140) The genetic code was cracked by:


141) Who proposed the concept of jumping genes?


142) Why a protein cannot be a genetic material?


143) In 'B' DNA (right handed clockwise model of DNA of Watson and Crick) base pairs are tilted by 1. In 'Z' DNA (left handed sinistral, anticlockwise zigzag DNA) tilting of base pairs is:


144) The helical model for DNA given by Watson and Crick was:


145) In function of 'DNA polymerase' is to help in the conversion:


146) During protein synthesis, amino acids recognize and get attached to t-RNA with help of:


147) Genes in the intervening non-functional DNA segments are called:


148) Which of the following is correct?


149) Genes are made up of:


150) Hargobind Khorana is credited for the synthesis of:


151) To mobile DNA elements which move into the genome through RNA copies are called:


152) During a cell cycle, the DNA undergoes replication:


153) Each codon present on m-RNA and anticodon present on t-RNA is composed of:


154) Defective copies of functional genes are called:


155) The structural stability of the double helix of DNA is ascribed largely to:


156) Which of the RNA is smallest and used in feeding of amino acid to a ribosome?


157) After reaching the cytoplasm the mRNA attaches itself to:


158) What was Linus Pauling's view on the structure of DNA?


159) Formation of new DNA strand during replication occurs in:


160) Which of the following can break and reseal DNA strand during replication?


161) Replication of DNA is:


162) When in a DNA, A-T becomes T-A and G-C becomes C-G, the pehnomenon is called:


163) DNA segments (genes) have been found to move out of choroplasts and go into mitochondria. These have been termed as:


164) DNA replication is:


165) In 'Z' DNA pitch of each turn of helix is:


166) The biochemical nature of gene (DNA) was shown by:


167) Diameter and pitch per turn of helix of 'A' model of DNA is:


168) 'Z' DNA shows:


169) The first gene successfully isolated by Shapiro et al in 1969 was the gene of:


170) Thymine dimers when present somewhere in the centre of polynucleotide strand would be excised by:


171) Approach of Meselson and Stahl to establish the semi-conservative replication of DNA was to use:


172) Which of the following enzymes is required for DNA to RNA formation?


173) Addition of sugar residue to proteins termed glycosylation occurs in:


174) Enzymes involved in an unwinding of DNA at replication are:


175) Aminoacyl synthetase enzyme takes part in:


176) tRNA attaches amino acid at its:


177) Who got the Nobel Prize in medicine in 1995 for showing how genes control human development in womb:


178) Teminism is:


179) During protein synthesis peptide bond is established between:


180) Which one of the following chemical characterisitics is not common to all living beings?


181) Because the amino acids are represented by more than one codon, the genetic code is said to be:


182) The messenger RNA is termed as a working copy of the exact information contained in a segment of DNA strand. The process is called:


183) In Rous Sarcoma virus:


184) If genes do not occur at constant locus in different members of a species, this confirms the concept of:


185) The genes which continuously change their position on a chormosome are called:


186) Certain genes do not generate functional m-RNA for any protein. Such genes are termed:


187) RNA directed DNA polymerase is:


188) Names-Nirenberg, Ochoa, Gamow, Khorana, Crick bring to your mind:


189) When mRNA is synthesised on DNA the unwanted DNA regions are removed and regions coding for amino acids are joined together. This process is referred to as:


190) Pyrimidine dimers in DNA are formed when the cells are exposed to:


191) DNA elements which can switch their position are called:


192) Initiation of polypeptide chain in protein synthesis is induced by:


193) Who among the following established that RNA is the genetic material?


194) On Laggin strand, new DNA is synthesized in short segments, called:


195) Resistance to antibiotics is a genetic process that spreads naturally from one type of bacterium to:


196) In vitro synthesis of polyribonucleotides and RNA was made by:


197) The scientist who first synthesised DNA in vitro was:


198) Artificial synthesis of DNA was done by:


199) mRNA constitutes about:


200) Barbara McClintock's work showed that in maize:


201) Beadle and Tatum worked on genetics of Neurospora of Biochemical mutations resulted in the development of a new science called:


202) The best method to improve genetic quality of mankind is:


203) Reference transcription in eukaryotes : What is the correct relation?


204) If a chromosomes is fractured at two points by X-rays, the resulting segments may show fusion at the site of breakage:


205) Which of the following antibiotics prevent polypeptide chain elongation in eukaryotes but not in bacteria?


206) The mitochondrial DNA differs from nuclear DNA in:


207) As per template theory, amino acid first combines with:


208) RNA synthesis is continued by RNA-polymerase and:


209) Genes which are active all the time synthesising substance needed by the cell are called?


210) Which statement is wrong about DNA?


211) If the bases sequence of one strand of DNA is GAT, TAG, CAT, GAC, what shall the sequence on its complementary strand?


212) Ligase enzyme is used for:


213) During protein synthesis amino acids recognise and get attached to tRNA with the help of:


214) What becomes established from the Wobble hypothesis?


215) Genetic code consists of:


216) Okazaki fragments are seen during:


217) The Tryptophan operon is an example of:


218) When two genetic loci produce identical phenotypes in cis as well as as trans position, they are considered to be:


219) Restriction Endonuclease is used for cutting:


220) Nuclease enzyme cause fragmentation of DNA at sites not protected by proteins. When pure DNA was digested with a nuclease, DNA fragments of all sizes were obtained but when chromatin was similarly digested DNA fragments of sizes that were obtained. This suggested that in the chromatin the histone proteins are associated with DNA all along its length:


221) Because most of the amino acids are represented by more than one codon the genetic code is said to be:


222) During elongation of polypeptide chain, sigma factor is:


223) During the replication of DNA the two daughter molecules are obtained in the following manner:


224) DNA contains the bases:


225) For structure of nucleic acid, which of the following statements is wrong:


226) In recent years, considerable attention is being given to DNA protein interactions, because expression of genes is regulated through binding of specific proteins on regulatory DNA sequences. The pattern of protein binding of DNA can be studied by:


227) There are several proteins that help to open up DNA double helix in front of the replication fork. These belong to the category of:


228) UV-rays lethal due to inactivation of:


229) Amino acids are transferred from cytoplasm to site of protein synthesis by:


230) ATP is not spent during:


231) Nature of DNA replication is:


232) The maximum concentration of RNA is found in:


233) An anticodon is a complementary to the nucleotide triplet in:


234) In bacterial chromosomes, the nucleic acid polymers are:


235) The nitrogenous organic base purine occuring in RNA is:


236) In cell cycle, DNA replication takes place in:


237) Protein synthesis in an animal cell takes place:


238) Which step of translation does not consume a high energy phosphate bond?


239) DNA synthesis can be specifically measured by estimating the incorpotation of radio labelled:


240) Three codons causing chain termination are:


241) The RNA that picks up specific amino acids from the amino acid pool in the cytoplasm to ribosome during protein synthesis is called:


242) In eukaryotes, after transcription of mRNA, some of its nucleotides are removed before it is translated into polypeptide. The nucleotides which are removed from mRNA are called:


243) If a completely radioactive double stranded DNA molecule undergoes two rounds of replication in a non-radioactive medium, what will be radioactive status of the four resulting molecules?


244) The chemical knives of DNA are:


245) Radioactive thymidine when added to the medium surrounding living mammalian cells gets incorporated into the newly synthesized DNA. Which of the following types of chromatin is expected to become radioactive if cells are exposed to radioactive thymidine as soon as they enter the S phase?


246) Human immuno deficiency virus (HIV) has a protein coat and a genetic material which is:


247) Proteins are synthesised by the process:


248) Correct sequence of code transfer during polypeptide formation is:


249) Which is true of DNA helicases?


250) Mechanism of DNA duplication is mainly:


251) During cell cycle, the DNA replication occurs in:


252) One bacterium which has extensively used in genetic engineering work in plants is:


253) One of the similarities between DNA and RNA is that both:


254) Protein synthesis occurs:


255) The transfer RNA molecule in 3D appears:


256) Maximum number of bases in plasmids discovered so far:


257) E. coli about to replicate was placed in a medium containing radioactive thymidine for five minutes. Then it was made to replicate in a normal medium. Which of following observation shall be correct?


258) Which of the following cut the DNA from specific places.


259) m-RNA is synthesised on DNA in template in which direction:


260) Types of RNA polymerase required in nucleus for RNA synthesis in eukaryotes:


261) Gene and cistron words are sometimes used synonymously because:


262) HIV has a protein coat and a genetic material which is:


263) Largest bacterial plasmid has Kilobases:


264) Cauliflower mosaic virus has:


265) DNA polymerase that helps in DNA replication is of:


266) In recent years, DNA sequence (nucleotide sequence) of mt-DNA and Y chromosomes were considered for the study of human evolution, because:


267) Genetic map is one that:


268) The linkage map of X-chromosome of fruitfly has 66 units, with yellow body gene (y) at one end and bobbed hair (b) gene at the other end. The reombination frequency bewteen these two genes (y and b) should be:


269) Degeneration of a genetic code is attributed to the:


270) Down's syndrome is caused by an extra copy of chromosome number 21. What percentage of offspring produced by an affected mother and a normal father would be affected by this disorder?


271) During translation initiation in prokaryotes, a GTP molecule is needed in:


272) During transcription, the DNA site at which RNA polymerase binds is called:


273) The total number of nitrogenous bases in human genome is estimated to be about:


274) Which of the following pairs is correctly matched with regard to the codon and the amino acid coded by it?


275) DNA repairing is done by:


276) The function of promoter of lac-operon is to:


277) Oncogense were discovered by:


278) When a mutation is limited to the substitution of one nucleotide for another, it is called:


279) During transcription, if nucleotide sequence of DNA strand, that is being coded is ATACG, then the nucleotide sequence in m-RNA would be:


280) During replication of a bacterial chromosome, DNA synthesis starts from the replication origin site and:


281) In the genetic code dictionary, how many codons are used to code for all the 20 essential amino acids?


282) Which one of the following triplet codes is correctly matched with its sepecificity for an amino acid in protein synthesis or as 'start' of 'stop' signal?


283) Find the correct match:


284) The codon for anticodon 3'UUA5' is:


285) Splicing of RNA depends on:


286) In lac operon system, lac gene-I codes for:


287) Which of the following is important for transcription?


288) Production of a human protein in bacteria by genetic engineering is possible because:


289) E.coli vells with a mutated Z gene of the lac operon cannot grow in medium containing only lactose as the source of energy because:


290) During transcription holoenzyme RNA polymerase binds to a DNA sequence and the DNA asumes a saddle-like structure at that point. What is that sequence called?


291) Which one of the following makes use of RNA as a template to synthesize DNA?


292) In the synthesis of which of the following, the DNA molecule is not directly involved?


293) Which one of the following hydrolyses internal phosphodiester bonds in a polynucleotide chain?


294) Transcription requires which of these enzyme?


295) Genes that are continuously functional and whose regulations are at tissue level as in kidney, liver are known as:


296) DNA duplication takes place during:


297) One gene-one enzyme hypothesis was posulated by:


298) Which antibiotic inhibits interaction between tRNA and mRNA during bacterial protein synthesis?


299) Amino acid sequence, in protein synthesis is decided by the sequence of:


300) During protein synthesis in an organism at one point the process comes to a halt. Select the group of the three codons from the following, from which any one of the three could bring about this halt.


301) The Okazaki fragments in DNA chain growth:


302) The length of DNA molecule greatly exceeds the dimensions of the nucleus in eukaryotic cells. How is this DNA accommondated?


303) A sequential expression of a set of human genes occurs when a steriod molecule binds to the:


304) During transcription, RNA polymerase holoenzyme binds to a gene promotor and assumes a saddle-like structure. What is it's DNA-binding sequence?


305) One gene-one enzyme relationship was established for the first time in:


306) Telomere repetitive DNA sequences control the function of eukaryote chromosomes because they:


307) Molecular basis of organ differentiation depends on the modulation in transcription by:


308) The two polynucleotide chains in DNA are:


309) Choose the wrong statement:


310) In the DNA molecule:


311) Which one of the following pairs of codons is correctly matched with their function or the single for the particular amino acid:


312) Polysomes formed by:


313) Which one of the following also acts as a catalyst in a bacterial cell?


314) Which of the nucleotide composition will be possible if DNA is double stranded?


315) Which of the following is incorrect?


316) In case of F. Griffith experiment on Streptococcus pneumoniae, which of the following is not able to cause pneumonia:


317) Which of the following photographed x-ray diffraction pictures of crystalline DNA?


318) Which of the following is more hydrate and more frequently found in living cells?


319) The right handed DNA can acquire a left handed structure at least over a short distance. It will:


320) Three types of DNA can be differentiated on the basis of their:


321) The DNA replication in most bacteria starts at a single point, origin and moves:


322) Which of the following unzips the two strands of DNA double helix?


323) What is the composition of larger subunit of prokaryotic ribosome?


324) Tetracycline inhibits protein synthesis in bacteria by inhibiting:


325) Which of the following act as elongation factors in prokaryotes?


326) Overlapping genes:


327) When gene resemble functional genes but do not produce functional substance are called:


328) Which statement is incorrect?


329) Virus genome replicates in:


330) For replication viruses use:


331) The activity of nuclease does not affect phage DNA because it has:


332) Match the list I and II and select the answering using the code given below the list:
1. Friedrick Griffith : Phenomenon of transformation
2. Gamow : A sequence of 3 nucleotide codes for a single amino acid
3. F. Miescher : Isolated DNA for the first time


333) Match the list I and II and select the correct answer using the code given below in the list:
1. Ligase : Joins short segments of DNA together
2. DNA polymerase : Cuts DNA at specific DNA sequence
3. Helicase : Breaks the hydrogen bonds between complementary pairs during DNA replication


334) In a hypothetical mRNA, the codon would normally be translated as follows:
UUG : Leu,
UUG : Leu,
UUU : Val,
UGU : Cys,
UAU : Tyr
If single G-residue is inserted between the second and 3rd bases: