Biotechnology Principles and Processes Class 12 Biology Exam Questions

Please refer to Biology For Biotechnology Principles and Processes Class 12 Biology Exam Questions provided below. These questions and answers for Class 12 Biology have been designed based on the past trend of questions and important topics in your class 12 Biology books. You should go through all Class 12 Biology Important Questions provided by our teachers which will help you to get more marks in upcoming exams.

Class 12 Biology Exam Questions Biotechnology Principles and Processes

SHORT ANSWER TYPE QUESTIONS 

Question. Identify the recognition sites in the given sequences at which E.coRI will cut and make sticky ends.
5´-GAATTC-3´ 3´-CTTAAG-5´
Answer.5’−G↓AATTC-3’
3’−CTTAA↑G-5’

Question. What is the role of ‘Ori’ in any plasmid?
Answer.Ori is a nucleotide sequence in plasmid vector which makes any piece of DNA linked to this sequence replicate with in host cells.
Ori also determines the copy number of linked DNA

Question. What are the two core techniques that enabled the birth of biotechnology?
Answer.The two core techniques that enabled the birth of modern biotechnology are:
Genetic engineering techniques to alter the chemistry of genetic material (DNA and RNA), so that it can be introduced to host organisms to change the phenotype of the host organism.
Maintenance of sterile ambience in chemical engineering processes to enable the growth of only the desired microbe/eukaryotic cell in large quantities for the manufacture of biotechnological products like antibiotics, vaccines, enzymes, etc.

Question. Make a list of tools of recombinant DNA technology
Answer.Key tools of recombinant DNA technology:
Restriction enzymes
Polymerase enzymes
Ligases
Vectors
Host organism.

Question. Why is it not possible for an alien DNA to become part of chromosome anywhere along its length and replicate?
Answer.For multiplication of any alien DNA, it needs to be a part of a chromosome which has a specific sequence known as ‘origin of replication’

Question. What is EcoRI? How does EcoRI differ from an exonuclease?
Answer.EcoRI is an endonuclease restriction enzyme which cut both the stands of palindromic DNA at a specific position of nitrogen base sequence (GAATTC) while exonuclease removes nucleotides from terminals of DNA strands.

Question. How are ‘Sticky ends’ formed on a DNA strand? Why are these so-called?
Answer.1. Restriction enzymes cut the 2 strands of DNA a little away from the centre of palindrome site, but between the same two bases on opposite strands. As a result, single-stranded over hanging stretches of DNA called sticky ends are left at each end.
2. The Sticky ends are named so because they form hydrogen bonds with their complementary cut counterparts. The stickiness helps in the action of DNA ligase.

Question. Study the given diagram and answer the questions

A] Name the restriction enzyme that recognises this palindrome.
B] Name the enzyme that link the DNA fragments.
Answer.A] EcoR1
B] DNA ligase

Question. Name the first plasmid used as vector.
Answer.pBR322.

Question. Why is it not possible for an alien DNA to become part of a chromosome anywhere along its length and replicate normally?
Answer.Alien DNA must be linked to ori or origin of replication site to start replication.

Question. Name two commonly used vectors in genetic engineering.
Answer.Plasmid and Bacteriophage.

Question. An extra chromosomal segment of circular DNA of a bacterium is used to carry gene of interest into the host cell. What is the name given to it?
Answer.Plasmid.

Question. Name the commonly used vector for trans formation in plant cell?
Answer.Agrobacterium tumefaciens.

Question. Differentiate between plasmid DNA and chromosomal DNA?
Answer.Plasmid DNA is extranuclear DNA, found in protoplasmic whereas chromosomal DNA is the nuclear or genetic DNA which is found within the nucleus.

Question. What is the role of Ori for cloning vector?
Answer.Ori: It is a genetic sequence that acts as the initiation site for replication of DNA. Any fragment of DNA, when linked to the ori region, can be initiated to replicate

Question. Why is it essential to have selectable marker in a cloning vector?
Answer.Selectable markers are essential to identify and eliminate non-transformants (no recombinant DNA), and selectively permitting the growth of the transformants (host cells bearing recombinant DNA).

Question. The gene of interest is cloned at which position in plasmid PBR322 to facilitate quick selection?
Answer.The gene of interest is inserted at restriction enzyme site located in any one of the antibiotic resistance genes or selectable marker gene. The restriction sites are Hind III, EcoR I, BamH I, Sal I, Pvu I, Pst I, Cla I and the selectable markers are ampR and tetR.

Question. State what happens when an alien gene is ligated at Sal I site of pBR322 plasmid.
Answer.If an alien gene is ligated at Sal I site of tetracycline resistance gene in the vector pBR322, the recombinant plasmid will lose its tetracycline resistance.

Question. Name the host cells in which microinjection technique is used to introduce an alien DNA.
Answer.The microinjection technique to introduce alien DNA is usually carried out in animal cell, i.e. directly into the nucleus.

Question. Name the enzyme used as an alternate selectable marker.
Answer.ᵝ –Galactosidase.

Question. Explain any two methods of vector less gene transfer?
Answer..(i)Microinjection-In this method rDNA is directly injected into the nucleus of an animal cell
(ii) Biolistics or gene gun-In this the target cells are bombarded with high velocity particles of gold or tungsten coated with DNA

Question. Name the source organism from which Ti plasmid is isolated. Explain the use of this plasmid in biotechnology
Answer.(i)Agrobacterium tumefaciens
(ii)The desired gene or segment of DNA can be ligated to this plasmid, and it is then used as a vector to introduce gene into the host plant.

Question. Why is Agrobacterium tumefaciens considered as a good cloning vector? Explain.
Answer.i)Agrobacterium tumefaciens
is a soil bacterium which causes diseases in many dicot plants? 
(ii)It is able to deliver a piece of DNA known as T-DNA, to transform the normal cells into tumour cells and direct these tumour cells to produce to chemicals required by the pathogen.

Question. Why is ‘Origin of replication’ (Ori) required to facilitate cloning into a vector?
Answer.Ori is a sequence from where replication starts and any piece of DNA to replicate in the host cell needs to be linked to it.
It also controls the copy number of the linked DNA. 

Diagram Type Question

Question. Which one of the following option is correct for A, B and C marked in the given diagram of recombinant DNA technology.

(a) A-Exonuclease; B-Ligases; C-Transformation
(b) A-Endonuclease; B-gyrase; C-Transformation
(c) A-Exonuclease; B-Hydrolase; C-Transduction
(d) A-Restriction endonuclease; B-Ligases;C-Transformation

Question. Identify the correct match for the given apparatus.

Apparatus                                                                     Function
(a) Gene gun                                                      Vectorless direct gene transfer
(b) Column  chromatography                             Separation of chlorophyll  pigments
(c) Sparged stirred tank bioreactor                       Carry out fermentation  process
(d) Respirometer                                                 Finding out rate of respiration

Question. The figure given below shows three steps (A, B, C) of Polymerase Chain Reaction (PCR). Select the option giving correct identification together with what it represents?

(a) B – Denaturation at a temperature of about 98°C separating the two DNA strands.
(b) A – Denaturation at a temperature of about 50°C.
(c) C – Extension in the presence of heat stable DNA polymerase.
(d) A – Annealing with two sets of primers.

Critical Thinking Questions

Question. The same basic techniques can be used to analyze the DNA from species as diverse as bacteria and humans because:
(a) all cells are identical.
(b) every organism has the same amount of DNA.
(c) the DNA sequences of all organisms are the same.
(d) DNA has a consistent structure in all organisms.

Question. Introduction of one or more genes into an organism which normally does not possess them or their deletion by using artificial means (not by breeding) comes under a branch called ________ .
(a) molecular biology
(b) cytogenetics
(c) genetic hybridization
(d) genetic engineering

Question. DNA ligases are enzymes that can be used to
(a) chop a large DNA molecule into small fragments.
(b) copy DNA fragments.
(c) insert the DNA from one species into the DNA of another species.
(d) separate DNA fragments based on their size.

Question. A biologist intends to use a polymerase chain reaction to perform a genetic task. The biologist probably is trying to
(a) discover new genes.
(b) clone a gene.
(c) cut DNA into many small fragments.
(d) isolate DNA from a living cell.

Question. Which of the following is not necessary to execute a polymerase chain reaction successfully?
(a) All four DNA bases
(b) Short DNA base primers
(c) DNA polymerase
(d) DNA library

Question. The linking of antibiotic resistance gene with the plasmid vector became possible with
(a) DNA ligase
(b) endonucleases
(c) DNA polymerase
(d) exonucleases

Question. What must be done before placing DNA into the electrophoretic chamber ?
(a) It must be ground up with mortar and pestle.
(b) It must be cut by restriction endonucleases.
(c) It must be treated with RNAase .
(d) None of the above

Question. What are the properties of a good vector?
(a) It should be ideally more than 10 kb in size.
(b) It should be able to replicate autonomously.
(c) It should have suitable marker genes.
(d) It should not be easy to isolate and purify.

Question. Restriction endonucleases hydrolyzes polynucleotide from
(a) only the 5′ end.
(b) from either terminal.
(c) at an internal phosphodiester bond.
(d) a phosphodiester bond within a specific sequence.

Question. Which of the following is used as a best genetic vector in plants?
(a) Bacillus thuringiensis
(b) Agrobacterium tumefaciens
(c) Pseudomonas putida
(d) All of the above

Question. In agarose gel electrophoresis, DNA molecules are separated on the basis of their
(a) charge only
(b) size only
(c) charge to size ratio
(d) all of these

Question. What type of enzyme is used in recombinant DNA technology to split a specific sugar phosphate bond in each strand of a DNA double helix ?
(a) Esterase
(b) Restriction enzyme
(c) Lipase
(d) Ligase

Question. Genetic engineering is possible, because
(a) we can cut DNA at specific sites by endonucleases like DNase I.
(b) restriction endonucleases purified from bacteria can be used in vitro.
(c) the phenomenon of transduction in bacteria is well understood.
(d) we can see DNA by electron microscope.