Case Study Questions Class 12 Biology Chapter 10 Biotechnology: Principles and Processes
CBSE Class 12 Case Study Questions Biology Biotechnology: Principles and Processes. Term 2 Important Case Study Questions for Class 12 Board Exam Students. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Biotechnology: Principles and Processes.
At Case Study Questions there will given a Paragraph. In where some Important Questions will made on that respective Case Based Study. There will various types of marks will given 1 marks, 2 marks, 3 marks, 4 marks.
CBSE Case Study Questions Class 12 Biology Biotechnology: Principles and Processes
Case Study 1
Biotechnology deals with techniques of using live organisms or enzymes from organisms to produce products and processes useful to humans. In this sense, making curd, bread or wine, which are all microbe-mediated processes, could also be thought as a form of biotechnology. However, it is used in a restricted sense today, to refer to such of those processes which use genetically modified organisms to achieve the same on a larger scale. Further, many other processes/techniques are also included under biotechnology. For example, in vitro fertilisation leading to a ‘test-tube’ baby, synthesising a gene and using it, developing a DNA vaccine or correcting a defective gene, are all part of biotechnology.
The European Federation of Biotechnology (EFB) has given a definition of biotechnology that encompasses both traditional view and modern molecular biotechnology. The definition given by EFB is as follows: ‘The integration of natural science and organisms, cells, parts thereof, and molecular analogues for products and services’.
Que. 1) ……………………………………………………………………………………. is a technique where live enzymes or organisms are used to make products or methods which are useful to the humans.
(a) Bio-technology
(b) Info-technology
(c) Medical technology
(d) Business technology
Que. 2) In the biotechnology, produced products and processes are useful to the …………………………………………………………………………………….
(a) Microbes
(b) Reptiles
(c) Humans
(d) Cockroach
Que. 3) The definition of Biotechnology is given by ……………………………………………………………………………………..
(a) FFB
(b) FBU
(c) BFE
(d) EFB
Que. 4) Which are the microbe-mediated processes in the biotechnology.
Que. 5) What are the different part of Biotechnology.
Answer Key
Que. 1)(a) Bio-technology.
Que. 2) (c) Humans.
Que. 3) (d) EFB.
Que. 4) Answer: The process of making wine, bread and curd are microbe-mediated processes in the Biotechnology.
Que. 5) Answer: Different parts of Biotechnology includes DNA vaccine development, correcting defective gene, and In-vitro fertilization.
Case study 2
The techniques of genetic engineering which include creation of recombinant DNA, use of gene cloning and gene transfer, overcome this limitation and allows us to isolate and introduce only one or a set of desirable genes without introducing undesirable genes into the target organism.
Most likely, this piece of DNA would not be able to multiply itself in the progeny cells of the organism. But, when it gets integrated into the genome of the recipient, it may multiply and be inherited along with the host DNA. This is because the alien piece of DNA has become part of a chromosome, which has the ability to replicate. In a chromosome there is a specific DNA sequence called the origin of replication, which is responsible for initiating replication. Therefore, for the multiplication of any alien piece of DNA in an organism it needs to be a part of a chromosome(s) which has a specific sequence known as ‘origin of replication’. Thus, an alien DNA is linked with the origin of replication, so that, this alien piece of DNA can replicate and multiply itself in the host organism. This can also be called as cloning or making multiple identical copies of any template DNA. The cutting of DNA at specific locations became possible with the discovery of the so- ‘molecular scissors’– restriction enzymes.
Que. 1) Which DNA sequence is responsible for initiating replication?
(a) Endonuclease
(b) Restriction DNA
(c) Gene clone
(d) Origin of replication
Que. 2) DNA sequence is mainly present in …………………………………………………………………………………………….
(a) Mitochondria
(b) Chromosomes
(c) Chloroplast
(d) Cytoplasm.
Que. 3) True or False
‘The piece of DNA don’t have ability to multiply itself in the progeny cell of an organism.’
(a) True
(b) False
Que. 4) Which creations are included in the genetic engineering?
Que. 5) Write name of molecular scissors which is useful in cutting DNA?
Answer Key
Que. 1)(d) Origin of replication.
Que. 2) (b) Chromosomes.
Que. 3) (a) True.
Que. 4) Answer: Creations of gene cloning, recombinant DNA and Gene transfer are included in the genetic engineering.
Que. 5) Answer: Restriction enzyme is a molecular scissor which is helpful in cutting DNA.
Case study 3
In the year 1963, the two enzymes responsible for restricting the growth of bacteriophage in Escherichia coli were isolated. One of these added methyl groups to DNA, while the other cut DNA. The later was called restriction endonuclease. The first restriction endonuclease–Hind II, whose functioning depended on a specific DNA nucleotide sequence was isolated and characterised five years later. It was found that Hind II always cut DNA molecules at a particular point by recognising a specific sequence of six base pairs. This specific base sequence is known as the recognition sequence for Hind II. Besides Hind II, today we know more than 900 restriction enzymes that have been isolated from over 230 strains of bacteria each of which recognise different recognition sequences. The convention for naming these enzymes is the first letter of the name comes from the genus and the second two letters come from the species of the prokaryotic cell from which they were isolated, e.g., EcoRI comes from Escherichia coli RY 13. In EcoRI, the letter ‘R’ is derived from the name of strain. Roman numbers following the names indicate the order in which the enzymes were isolated from that strain of bacteria
Restriction enzymes belong to a larger class of enzymes called nucleases. These are of two kinds; exonucleases and endonucleases. Exonucleases remove nucleotides from the ends of the DNA whereas, endonucleases make cuts at specific positions within the DNA. Each restriction endonuclease functions by ‘inspecting’ the length of a DNA sequence. Once it finds its specific recognition sequence, it will bind to the DNA and cut each of the two strands of the double helix at specific points in their sugar -phosphate backbones. Each restriction endonuclease recognises a specific palindromic nucleotide sequences in the DNA.
Que. 1) How many enzymes are there which can restrict growth of bacteriophage in E.coli?
(a) One
(b) Two
(c) Three
(d) Four
Que. 2) The letter ‘R’ in the EcoRI is a name of ……………………………………………………………………………………..
(a) Strain
(b) Species
(c) Genus
(d) Kingdom
Que. 3) In the naming of enzyme, first letter of name belongs to ……………………………………………………………………………………….
(a) Species
(b) Order
(c) Strain
(d) Genus
Que. 4) Which enzyme belongs to nucleases class of enzymes?
Que. 5) Write names and role of restriction enzymes.
Answer Key
Que. 1)(b) Two.
Que. 2) (a) Strain.
Que. 3) (d) Genus.
Que. 4) Answer: Restriction enzyme mainly belongs to nucleases class of enzymes.
Que. 5) Answer: Two kinds of restriction enzymes are there. First is endonuclease which can cut the DNA at specific position. Second is exonuclease that remove nucleotides from the DNA (End of DNA).
Case study 4
When cut by the same restriction enzyme, the resultant DNA fragments have the same kind of ‘sticky-ends’ and, these can be joined together (end-to-end) using DNA ligases The cutting of DNA by restriction endonucleases results in the fragments of DNA. These fragments can be separated by a technique known as gel electrophoresis. Since DNA fragments are negatively charged molecules they can be separated by forcing them to move towards the anode under an electric field through a medium/matrix. Nowadays the most commonly used matrix is agarose which is a natural polymer extracted from sea weeds. The DNA fragments separate (resolve) according to their size through sieving effect provided by the agarose gel. Hence, the smaller the fragment size, the farther it moves. The separated DNA fragments can be visualised only after staining the DNA with a compound known as ethidium bromide followed by exposure to UV radiation (you cannot see pure DNA fragments in the visible light and without staining). You can see bright orange coloured bands of DNA in an ethidium bromide stained gel exposed to UV light.
The separated bands of DNA are cut out from the agarose gel and extracted from the gel piece. This step is known as elution. The DNA fragments purified in this way are used in constructing recombinant DNA by joining them with cloning vectors.
Que. 1) ………………………………………………………………………… is used to join sticky ends of DNA.
(a) DNA Ligase
(b) DNA Host
(c) DNA restriction
(d) None of them
Que. 2) On the basis of ……..………………………………………………………………., fragments of DNA gets separated in the Gel electrophoresis.
(a) Nucleotide
(b) Colour
(c) Shape
(d) Size
Que. 3) After DNA fragment separation, DNA is stained by ……………………………………………………………………… for the visualization.
(a) Toluidine
(b) Ethidium bromide
(c) Sulphuric acid
(d) Phloroglucinol
Que. 4) Name the technique which useful in the separation of fragments of DNA.
Que. 5) Name the matrix which is extracted from sea weed and is a natural polymer.
Answer Key
Que. 1)(a) DNA Ligase.
Que. 2) (d) Size.
Que. 3) (b) Ethidium bromide.
Que. 4) Answer: Gel electrophoresis is the technique which useful in the separation of fragments of DNA.
Que. 5) Answer: Agarose is the matrix which is extracted from sea weed and is a natural polymer.
Case Study 5
Since DNA is a hydrophilic molecule, it cannot pass through cell membranes. Why? In order to force bacteria to take up the plasmid, the bacterial cells must first be made ‘competent’ to take up DNA. This is done by treating them with a specific concentration of a divalent cation, such as calcium, which increases the efficiency with which DNA enters the bacterium through pores in its cell wall. Recombinant DNA can then be forced into such cells by incubating the cells with recombinant DNA on ice, followed by placing them briefly at 420C (heat shock), and then putting them back on ice. This enables the bacteria to take up the recombinant DNA. This is not the only way to introduce alien DNA into host cells. In a method known as micro-injection, recombinant DNA is directly injected into the nucleus of an animal cell.
In another method, suitable for plants, cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA in a method known as biolistics or gene gun. And the last method uses ‘disarmed pathogen’ vectors, which when allowed to infect the cell, transfer the recombinant DNA into the host. Now that we have learnt about the tools for constructing recombinant DNA, let us discuss the processes facilitating recombinant DNA technology.
Que. 1) In …………………………………………………………………………… method, recombinant DNA is transferred into the host to infect the cell.
(a) Restriction method
(b) Gene Gun
(c) Biolistics
(d) Disarmed pathogen
Que. 2) Biolistics or Gene gum method is suitable for ………………………………………………………………………………………..
(a) Reptiles
(b) Plants
(c) Birds
(d) Insects
Que. 3) Calcium cation increases efficiency of …………………………………………………………………………….. for the bacterium entry.
(a) Cell
(b) DNA
(c) RNA
(d) Ribosome
Que. 4) Why the DNA cannot pass through cell membrane?
Que. 5) In which method, the recombinant DNA is injected directly into animal’s nucleus?
Answer Key
Que. 1)(d) Disarmed pathogen.
Que. 2) (b) Plants.
Que. 3) (b) DNA.
Que. 4) Answer: DNA is basically a hydrophilic molecule and cell membrane is hydrophobic in nature. Hence, the DNA cannot pass through cell membrane.
Que. 5) Answer: In the micro-injection method, the recombinant DNA is injected directly into animal’s nucleus.