Multiple choice question for engineering
1. It is very important to study lambda biology as lambda phages are used for cloning purposes. Which of the statement is true for lambda phage?
a) It is an example of temperate phage
b) The fate of the phage is decided before it infects the cell
c) The lysis fate is that where the phage inserts it genome into the bacterial genome and the replication goes on
d) The lysogenic fate is that where the phage infects the cell and lysis is carried out
2. Choose the correct statement for the infectious particle of lambda phage.
a) It is single stranded genome
b) It is circular double stranded genome
c) The ends are blunt with cos (cohesive) sequences
d) The ends are created by cleavage at cos sites during phage packaging
3. Some changes are encountered in the infectious particle as it infects the cell. Choose the incorrect statement.
a) The infectious particle circularizes upon causing infection by annealing at cos sites
b) There are two promoters present, PR and PL
c) Upon infection only PR is activated
d) Promoters give rise to immediate early transcripts
4. The immediate early transcripts direct synthesis of which genes?
a) N genes
b) cro genes
c) Both N and cro genes
d) PR and PL genes
5. What is the function of N gene?
a) It promotes the function of terminators
b) It overrides the function of terminators
c) It promotes the production of cro gene
d) It is responsible for making the infectious particle linear
6. Choose the correct statement for cII gene and its related function?
a) The transcription is extended to the region of cII gene and it is termed as late transcription
b) They are responsible for deactivating the promoter for repressor establishment
c) This promoter is responsible to decide whether the life cycle would be lysogenic or lytic
d) cII gene is responsible for other gene which is gene cIII
7. Which gene is required for the lysogenic phage to be adopted?
d) All the three genes are interrelated
8. Choose the incorrect statement for lysogenic mode.
a) PRE forms cI gene product which is responsible for activation of promoters
b) The cII protein is responsible for interfering with cro and Q proteins and they are required for lytic life cyle
c) The cII protein activates the promoter PINT
d) The Int protein with host protein is responsible for site specific recombination
9. Choose the correct statement for cI gene.
a) It represses only cII gene
b) It activates cII gene and represses cIII gene
c) It represses both cII and cIII gene
d) It activates both cII and cIII gene
1. Bacteriophage Mu is also a phage, choose the correct statement for it.
a) It is an example of temperate phage
b) It is packaged into heads containing 50 kbp of DNA
c) When the phage replicates it goes transposition only a few times
d) Mu can’t be used for cloning in vivo
2. Choose the incorrect statement for ‘Mini Mu’?
a) It is produced by cloning of bacteriophage Mu in vivo
b) It contains reduced phage genome
c) It doesn’t contains replication of origin of plasmid
d) A selectable marker is added
3. Which of the following is not included as a step for cloning mini Mu in vivo?
a) A culture of target strain, whose DNA we want to clone is infected with mini Mu
b) The phage is inserted at multiple sites in the genome
c) Some of the packaged strain is flanked by two mini Mu genes
d) The packaged phage is introduced into a second strain and Mu would replicate as a phage
4. If recombination takes place between elements in the second strain, it would replicate by origin of replication of mini Mu. Is the given statement true or false.
5. Which of the following is a restriction for cloning in bacteriophage Mu?
a) It is limited to handling only small number of phage particles
b) It relies on whether the DNA is flanked by two mini Mu genes or not
c) Recombination between the elements in the second strain is not a restriction
d) Fragments of any genomic DNA can be cloned irrespective of the fact whether or not the phage can replicate in it or not
6. What is the size of the insert that can be accommodated in the head of bacteriophage PI?
a) 30-40 kbp
b) 80-95 kbp
c) 110-115 kbp
d) 200-300 kbp
7. What is the function of pac site in the bacteriophage PI?
a) It is responsible for initiation of packaging
b) It is responsible for termination of packaging
c) It is responsible for initiation of replication
d) It is responsible for termination of replication
8. What is the function of loxP sites?
a) It is responsible for linearization of DNA in the host bacterium
b) It is responsible for circularization of DNA in the host bacterium
c) It is responsible for conversion of single stranded DNA into double stranded DNA
d) It is responsible for conversion of double stranded DNA into single stranded DNA
9. Which of the following is not included as a step in cloning in bacteriophage PI?
a) The growth of vector is done as a plasmid by using pBR322 origin of replication
b) Cleaving with BamH1 is done and then products cleaved with Sau3A are ligated
c) Incubation with mutant lysogen is done which doesn’t cleaves the recombinants at pac sites
d) Incubation is done with mutant lysogen which doesn’t contains head and tail proteins
10. What happens after packaging is carried out in the phage head?
a) A sequence dependent cleavage of DNA is carried out
b) A sequence independent cleavage of DNA is carried out
c) They are linearized before they are infected into the bacterial cells
d) They are circularized before they are infected into the bacterial cells
11. Circularization must take place in the bacterial cells before the replication starts. The given statement is true or false?
12. How many origin of replication are there once the cyclization is carried out by loxP sites?
13. Choose the incorrect statement for PAC vectors.
a) In these vectors, the phage packaging signals are removed but the two P1 origin of replication persist
b) They resemble BAC vectors
c) They accept an insert of upto 300 kbp
d) Instability is observed
14. Choose the correct statement in respect to sacB gene?
a) The cloning site for PAC lies on the side of sacB gene
b) It is responsible for producing an enzyme which is responsible for catalysing sucrose into glucose and fructose
c) Expression of sacB in the presence of sucrose is beneficial
d) Levan is non-toxic for E. coli
15. Selection of molecules by lack of inserts on the basis of sacB gene is known as:
a) positive selection
b) negative selection
c) counter selection
d) sacB selection
1. The process of amplification of specific DNA sequences by an enzymatic process is termed as:
b) polymerase chain reaction (PCR)
2. What are primers?
a) Primers are the short sequences at the end of the nucleotide sequences which are used for amplification
b) Primers are the short sequences which are complementary to the nucleotides at the end of the sequence which is to be amplified
c) Primers are the short sequences present anywhere in the nucleotide sequence to be amplified
d) Primers are the short sequences which are complementary to the nucleotides anywhere in the sequence to be amplified
3. A reaction mixture for PCR consists of:
a) heat unstable polymerase
b) primers in limited amount
c) deoxynucleoside triphosphate (dNTPs)
d) a region complementary to the sequence to be amplified
4. Which of the following is a characteristic of Taq polymerase?
a) It is a RNA polymerase
b) It is heat stable
c) It is obtained from thermophilic bacterium and can be grown in laboratory below a temperature of 75 degrees
d) It is used in cellular synthesis processes and the optimum temperature is atleast 90 degrees
5. These are steps taken in carrying out the PCR reaction:
i) Attaching of primers by cooling
ii) Denaturation of strands
iii) DNA synthesis
Which is the correct order?
(Mentioned from starting to ending the reaction)
6. Which of the following is not a condition for PCR?
a) Initial melting carried out for 5 minutes at 94 degrees
b) Initial melting followed by 30 cycles each consisting of melting for 1 minute at 94 degrees
c) Renaturation for 5 minutes at 60 degrees
d) DNA synthesis at 72 degrees for 1.5 minutes
7. Primers and polymerases are added again during the reaction, because they get consumed as the reaction proceeds. Is the given statement true or false?
8. All the molecules generated during PCR will not be full length. Some will also be of intermediate length. Which of the statements is correct?
a) After first cycle, majority of the molecules will be full length and only some will be of intermediate length
b) In the next cycle, each intermediate molecule will generate one intermediate molecule and one target molecule
c) The number of full length molecules increase as number of cycles proceed
d) The number of intermediate molecules increase geometrically and the number of target molecules increase arithmetically
9. Which of the following activity is not present in Taq polymerase?
a) 5’-3’ polymerase
b) 5’-3’ exonuclease
c) 3’-5’ exonuclease
d) Both 5’-3’ polymerase and 5’-3’ exonuclease
10. Choose the correct statement.
a) Taq polymerase is having high processivity
b) Processivity is defined in this case as synthesis of DNA by polymerase
c) It requires a 5’ end for the elongation to take place
d) The maximum size of the molecules which can be synthesized is 10kbp
11. What is the half life cycle for Taq polymerase?
a) 40 minutes
b) 80 minutes
c) 10 minutes
d) 50 minutes
12. Taq polymerase incorporates which residue at 3’ end?
13. Polymerases are also available from other Thermus species. Which of the following is correct?
a) Thermus flavus gives Tfl enzyme
b) Thermus thermopilus gives Tfl enzyme
c) They are having proof reading activity
d) Thermus flavus gives Tth enzyme
14. Polymerases are available with proof reading activity. Which of the following are the characteristics of these types of polymerases?
a) They add a A residue at 3’ end
b) They are obtained from Thermococcus litoralis
c) They can’t be obtained from archaebacteria
d) The marine bacteria from which they are obtained grow at temperatures lower than that of Thermus aquatics
15. Thermococcus litoralis grows at a temperature upto 98 degrees. The given statement is true or false?
1. Ligation is defined as:
a) Alignment of only double stranded DNA molecules at the ends and the formation of phosphodiester bonds between both the strands
b) Alignment of either of the double or single stranded DNA molecules and formation of glycosidic bonds between both the strands
c) Alignment of either of the double or single stranded DNA molecules and then formation of phosphodiester bonds. The bond can be between either one or both the strands
d) Alignment of single stranded DNA molecules and formation of glycosidic bonds between these strands
2. If only one bond is broken in the sugar-phosphate backbone, it is called as:
3. How many categories of ligation reaction are there on the basis of ends created?
4. In the case of blunt-end ligation, blunt ends can be generated by:
a) simply the action of restriction endonuclease which gives straight ends
b) the polishing of staggered ends
c) both the action of restriction endonuclease which give straight ends and polishing of staggered ends
d) by the action of restriction endonuclease which gives staggered ends
5. The ligation reaction is more efficient in which case?
a) Blunt end ligation
b) Sticky end ligation
c) Both have same efficiency
d) Depends on the reaction conditions
6. The sticky ends are held together by which type of bonds?
a) Hydrogen bond
b) Covalent bond
c) Ionic bond
d) Van-der-waal forces
7. Why sticky ended ligations are carried out at temperatures lower than room temperature?
a) It is so because the vibrational and kinetic energy of the molecules at room temperature is lower than that of the energy required to break the bonds holding the ends
b) The energy required to break the bonds holding the ends is very less than that of the kinetic and vibrational energy at room temperature
c) The enzyme carrying out ligation is unstable at low temperature
d) The sticky ends created, don’t just religate at low temperature
8. Ligation reaction can be both intramolecular and intermolecular in nature. True or false?
9. If a ligation reaction is being carried out and recircularization is observed, which type of reaction is being carried out?
c) Both observe recircularization equally
d) Recircurlization is not possible in any of the case
10. What is the kinetics of the intramolecular and intermolecular ligation reactions?
a) Second order kinetics for intramolecular and first order for intermolecular
b) First order kinetics for intramolecular and second order for intermolecular
c) Both are first order
d) Both are second order
11. What are the effects of increasing concentration of reaction components?
a) It increases chances of ligation in both intramolecular and intermolecular reactions
b) It increases chances of ligation only in intermolecular and no effect on intramolecular
c) It decreases chances of ligation in intramolecular and increase in that of intermolecular
d) It decreases chances of ligation in both types of reaction
1. Choose the incorrect statement for cDNA libraries.
a) They constitute of DNA copies produced from the RNA sequences and usually mRNA
b) They represent expressed sequences
c) Introns are not represented
d) Comparison of cDNA sequences with genomic sequences leads to determination of polyadenylation sites
2. A times partial sequencing of cloned cDNAs is carried out. These cDNA are known as:
a) expressed RNA sequences
b) expressed sequence tags (ESTs)
c) expressed cDNA sequences
3. Polyadenylation of RNA species is an important criterion for the production of cDNA species. Which of the following holds true?
a) Polyadenylation should be at 3’ end
b) Eukaryotic mRNAs are mostly non-polyadenylated
c) Bacterial mRNAs and organelle mRNAs are polyadenylated
d) It is carried out by addition of T residues after synthesis
4. Choose the incorrect statement for oligo-dT cellulose.
a) It is used for separation of polyadenylated mRNA from other mRNA
b) oligo-dT are covalently attached to the solid support via OH bonds
c) A solution containing RNA is passed through the column
d) Poly A tail attaches to the oligo-dT by ionic bonds
5. Poly A tail from the column is eluted by using high salt concentration. Is the given statement is true or false.
6. At times streptavidin is used in place of cellulose. Choose the correct statement for this alternative.
a) oligo-dT streptavidin conjugate can be extracted by magnetic beads
b) The magnetic beads are attached with activin
c) Recovery is not based on the magnetic properties of the beads
d) The interaction between polyA tail and the oligo-dT is reduced
7. Choose the correct with respect to RNA molecules.
a) They are less labile than DNA molecules
b) The 2’ hydroxyl group of ribose group decreases the activity
c) There is no less of activity while boiling
d) Baking of glassware, treatment with UV can be used for protection against degradation
8. What is the basis of RNaseH method?
a) It is based on RNA synthesis by DNA strand
b) It is based on complementary DNA synthesis by RNA strand through reverse transciptase
c) It is based on complementary DNA synthesis by RNA strand through RNaseH enzyme
d) It is based on getting double strand RNA from a single strand
9. The first step for RNaseH method is to anneal a chemically synthesized oligo-dT primer to the 3’ polyA tail of RNA. Is the given statement true or false?
10. For the synthesis of second DNA strand, incorporated oligo-dT is of no use. Why?
a) It is so because it is unstable
b) It is so because it is at the 3’ end of the template molecule
c) It is so because it would be unable to initiate replication
d) It is so because it is detaches itself after first strand synthesis