CBSE Class 12 Biology Biotechnology Principles and Processes MCQs Set E

Case Based Questions

1. Read the following and answer any four questions from (i) to (v) given below
‘The vectors are DNA molecules that can carry a foreign DNA segment and replicate inside the host cell. Vectors may be plasmids, bacteriophages (viruses that attack bacteria), cosmids, yeast artificial chromosomes (YACs), Bacterial artificial chromosomes (BACs) and viruses. The most widely used, versatile, easily manipulated vector PBR 322 is an ideal plasmid vector. Features that are required to facilitate cloning into a vector includes origin of replication (Ori) which is a specific sequence of DNA bases responsible for initiating replication, selectable marker genes and cloning sites.

Question. p in pBR 322 denotes that it is a
(a) plasmid
(b) prokaryote
(c) protist
(d) plant cell

Answer: A

Question. Ori is a specific DNA sequence that help in
(a) attachment of primers
(b) initiation of replication
(c) extension of DNA base
(d) initiation of denaturation.

Answer: B

Question. A and B shown in the figure respectively indicates

(a) Pvu II and Cla I
(b) ROP and Sal l
(c) ampR and tetR
(d) tetR and ampR.

Answer: C

Question. Selectable markers in vector
(a) are responsible for replication
(b) help in selecting transformants from non-transformants
(c) code for proteins involved in the replicating plasmids
(d) contain unique recognition sites.

Answer: C

Question. Plasmid vectors are
(a) dsDNA molecule
(c) present in bacteria and yeast
(b) extra-chromosomal
(d) all of the options

Answer: D

2. Read the following and answer any four questions from (i) to  (v) given below:
When you insert a piece of alien DNA into a cloning vector and transfer it into a bacterial, plant or animal cell, the alien DNA gets multiplie(d) In almost all recombinant technologies, the ultimate aim is to produce a desirable protein. Hence, there is a need for the recombinant DNA to be expresse(d) The foreign gene gets expressed under appropriate conditions. The expression of foreign genes in host cells involve understanding many technical details. After having cloned the gene of interest and having optimised the conditions to induce the expression of the target protein, one has to consider producing it on a large scale. Can you think of any reason why there is a need for large-scale production? If any protein encoding gene is expressed in a heterologous host, it is called a recombinant protein. The cells harbouring cloned genes of interest may be grown on a small scale in the laboratory. The cultures may be used for extracting the desired protein and then purifying it by using different separation techniques.

Question. Which of the following should be chosen for best yield if one were to produce a recombinant protein in large amounts?
(a) A continuous culture system
(b) A stirred-tank bioreactor without in-lets and out-lets
(c) Laboratory flask of the largest capacity
(d) None of the above

Answer: A

Question. The process of separation and purification of expressed protein before marketing is called
(a) upstream processing
(b) downstream processing
(c) bioprocessing
(d) postproduction processing

Answer: B

Question. Genetically engineered bacteria is used for the production of:
(a) Thyroxine
(b) Human insulin
(c) growth hormone
(d) None of the above

Answer: B

Question. Construction of recombinant DNA involves:
(a) cleaving and joining of DNA segments with endonuclease
(b) cleaving DNA segments with endonuclease and re-joining with ligase
(c) cleaving and re-joining DNA segments with ligase
(d) cleaving DNA segments with ligase and re-joining with endonuclease

Answer: B

Question. Any DNA molecule that has the ability to replicate in an appropriate host cell, to which the desired gene are integrated for cloning:
(a) Plasmid
(b) Linker
(c) Vector
(d) adapter

Answer: C

3. Read the following and answer any four questions from (i) to  (v) given below:
Rajat is a student of biotechnology. His professor tells him that for transformation with recombinant DNA the bacterial cells must be made capable of taking up DNA as DNA do not pass through membrane. While doing experiment in the lab, Rajat noticed that bacterial cells were not taking up the foreign DNA even after treating it with sodium ion. He asked his professor, the reason behind this. His professor explained that he should check the valency and charge of the ion that he is using for the treatment.

Question. It is difficult for DNA to pass through the membrane as
(a) it is a hydrophilic molecule
(b) it is a hydrophobic molecule
(c) it is a circular molecule
(d) it changes its shape when it comes in contact with host cell

Answer: A

Question. What type of ions are used for DNA mediated gene transfers?
(a) Divalent anions
(b) Divalent cations
(c) Monovalent cations
(d) Monovalent anions

Answer: B

Question. rDNA stands for
(a) reduced DNA
(b) red DNA
(c) recombinant DNA
(d) related DNA

Answer: C

Question. Which of the following statements with regard to DNA is correct?
(a) DNA is a positively charged molecule having two polynucleotide chains.
(b) Nitrogen bases of two polynucleotide chain form complementary pairs. i.e., A opposite G and T opposite (c)
(c) Backbone of DNA chain is built up of alternate deoxyribose sugar and phosphate group.
(d) Both (a) and (c)

Answer: C

Question. Assertion: Competent host is essential for transformation with rDN(a)
Reason: Transfer of DNA in a prokaryotic cell is called transfection.
(a) Both assertion and reason are true and reason is the correct explanation of assertion.
(b) Both assertion and reason are true but reason is not the correct explanation of assertion.
(c) Assertion is true but reason is false.
(d) Both assertion and reason are false.

Answer: C

4. Read the following and answer any four questions from (i) to  (v) given below:
The cells can also be multiplied in a continuous culture system wherein the used medium is drained out from one side while fresh medium is added from the other to maintain the cells in their physiologically most active log/exponential phase. A stirred-tank reactor is usually cylindrical or with a curved base to facilitate the mixing of the reactor contents. The stirrer facilitates even mixing and oxygen availability throughout the bioreactor. Alternatively, air can be bubbled through the reactor. If you look at the figure closely you will see that the bioreactor has an agitator system, an oxygen delivery system and a foam control system, a temperature control system, pH control system and sampling ports so that small volumes of the culture can be withdrawn periodically.

Question. Micro-organisms can be grown in the bioreactors by
(a) Support growth system
(b) Agitated growth system
(c) Suspende(d) growth system
(d) Both (a) and (c)

Answer: D

Question. The components of a bioreactor are:
(a) An agitator system
(b) An oxygen delivery system
(c) A foam control system
(d) All of these

Answer: D

Question. The bioreactor is not capable of:
(a) Producing aseptic conditions
(b) Meeting containment regulations
(c) Controlling pH
(d) Produce electricity

Answer: D

Question. The small-scale bioreactors have volume of:
(a) 5-10 litres
(b) 10-20 litres
(c) 1-10 litres
(d) 1-20 litres

Answer: A

Question. Sparger in stirred tank bioreactor helps in:
(a) Proper gas distribution
(b) Proper mixing of medium
(c) Measuring temperature of medium
(d) Better sterility

Answer: A