Biotechnology and It's Applications

The human protein named $\alpha-1$-antitrypsin, obtained from transgenic animals, is used for the treatment of emphysema.

Transgenic models exist for the study of other diseases, such as Alzheimer's disease, rheumatoid arthritis and cystic fibrosis.

Specific Bt toxin genes were isolated from Bacillus thuringiensis and incorporated into the several crop plants such as cotton. The choice of genes depends upon the crop and the targeted pest, as most Bt toxins are insect-group specific. The toxin is coded by a gene named cry. The proteins encoded by the genes cryIAc and cryIIAb control the cotton bollworms, that of cryIAb controls corn borer. So, the correct answer is crylAc for cotton bollworms and crylAb for corn borer that is represented in option (1)

Bt toxin protein exists as inactive protoxins, but once an insect ingests the inactive toxin, it is converted into an active form of toxin due to the alkaline pH of the gut which solubilises the crystals.

The correct answer is bacterium.

In 1983, Eli Lilly, an American company, prepared two DNA sequences corresponding to 'A' and 'B' chains of human insulin and introduced them in plasmids of E.coli (a gram negative bacterium) to produce insulin chains.

Option (D) is the correct answer because the correct sequence of action of toxin in Bt. cotton is

B. Bacillus thuringiensis produces crystals with toxic insecticidal proteins.

E. The toxin proteins exist as inactive protoxins in bacteria.

C. The alkaline pH solubilises the crystals.

A. The inactive toxin converted into active form due to alkaline pH of gut of insect.

D. The activated toxin binds to the surface of midgut cells, creates pores and causes death of the insect.

Hence, $\mathrm{B} \rightarrow \mathrm{E} \rightarrow \mathrm{C} \rightarrow \mathrm{A} \rightarrow \mathrm{D}$ is the correct order.

Totipotency is defined as the capacity to generate a whole plant from any cell of the plant.

The correct answer is option (3) as specific Bt toxin genes were isolated from Bacillus thuringiensis and incorporated into the several crop plants such as cotton. The choice of genes depends upon the crop and the targeted pest as most Bt toxins are insect-group specific. The toxin is coded by a gene named cry. There are a number of them, for example, the proteins encoded by the genes cry IAc and cry IIAb control the cotton bollworms, that of cry IAb controls corn borer.

When a piece of DNA carrying a gene of interest is transferred into an alien organism, its fate depends on several factors, including the mechanisms it has for replication, integration, and inheritance. Here is an analysis of each statement provided:

A. The piece of DNA would be able to multiply itself independently in the progeny cells of the organism.
This is incorrect unless the DNA contains an origin of replication that is compatible with the host cell's replication machinery.

B. It may get integrated into the genome of the recipient.
This is a likely scenario if the DNA has sequences that facilitate recombination with the host genome or if the host has natural mechanisms of DNA integration such as those observed in bacteria with transformation capabilities, or other eukaryotic organisms with similar processes.

C. It may multiply and be inherited along with the host DNA.
This statement can be true if the introduced DNA is replicated along with the host DNA, possibly through integration into the host genome or existence in the form of an episome that replicates independently yet synchronously with the host DNA.

D. The alien piece of DNA is not an integral part of chromosome.
This statement is generally accurate before integration. The introduced DNA, before integration, exists extrachromosomally and thus is not part of any chromosome, unless mechanisms are present for its integration into the host genome.

E. It shows ability to replicate.
This statement depends on specific sequences in the DNA, such as the origin of replication compatible with the host cell's machinery, mentioned in statement A. Without these, it will not replicate independently.

Given these explanations, the most accurate answer that describes the fate of the DNA in the recipient organism is:

Option C: B and C only
'B' is correct as the DNA may integrate into the host genome, and 'C' is correct as the DNA might also multiply if replicated in sync with the host organism's DNA, particularly if it integrates or exists as an episome compatible with the host's cellular machinery.

In somatic hybridization, the fusion of protoplasts from different plant varieties or species is a key technique. Protoplasts are plant cells that have had their cell walls enzymatically removed, exposing the cell membrane. This condition allows for the direct fusion of cellular contents including the nucleus and cytoplasm from different cells, facilitating recombination and the formation of a hybrid cell. The process of fusion typically involves techniques such as electrofusion or chemical treatments to encourage the protoplasts to merge.

Looking at the options provided:

• Option A: Callus – This is not correct. A callus is a mass of unorganized plant cells that are generally not involved in fusion during somatic hybridization but are rather a product of the culture of somatic cells.
• Option B: Somatic embryos – These are not the direct subjects of fusion in somatic hybridization. Somatic embryos can develop from hybrid cells, but they themselves are not fused; they are derived from somatic cells under appropriate conditions.
• Option C: Protoplasts – This is correct. Protoplasts are indeed what are fused in somatic hybridization to combine the genetic material from two different plants or varieties.
• Option D: Pollens – These do not fuse in somatic hybridization. Pollen fusion is more relevant to sexual reproduction and breeding, not somatic cell procedures.

Therefore, the correct answer is Option C: Protoplasts.

To provide the correct answer, let's evaluate each option by matching the items from List I with their corresponding descriptions from List II:

• $\alpha$ -I antitrypsin - This is a protease inhibitor and its deficiency leads to emphysema due to the degradation of the lung tissue. Therefore, $\alpha$ -I antitrypsin corresponds to Emphysema (III).
• Cry IAb - Part of a family of proteins from Bacillus thuringiensis used as a biological pesticide. Cry IAb is notably effective against certain types of Lepidoptera, including the European Corn Borer (IV).
• Cry IAc - This is also a protein from Bacillus thuringiensis and is notably effective against Cotton Bollworm (I).
• Enzyme replacement therapy - Typically used for treating deficiencies in certain enzymes; one prevalent example is Adenosine Deaminase (ADA) deficiency, which leads to immune deficiencies (II).

Let's match these back to the original options provided:

• A-III ($\alpha$ -I antitrypsin matches with Emphysema)
• B-IV (Cry IAb matches with Corn Borer)
• C-I (Cry IAc matches with Cotton Bollworm)
• D-II (Enzyme replacement therapy matches with ADA deficiency)

Based on these matches, the correct option would be:

Option C: A-III, B-IV, C-I, D-II

The incorrect statement among the provided options is:

Option C: Bio-reactors are used to produce small scale bacterial cultures.

Explanation:

Bio-reactors, also known as fermenters, are primarily utilized for scaling up microbial processes to industrial scales. They are designed to support the growth of a high density of cells and microbes under controlled conditions to produce large volumes of biochemical products such as enzymes, pharmaceuticals, and other biologically active compounds. While bio-reactors can technically be used for small-scale laboratory experiments, their main application and design focus is on large-scale production.

Other Options:

Option A: This statement is correct. Bio-reactors are specifically designed to provide optimal conditions such as temperature, pH, oxygen supply, and nutrients for the growth of microorganisms or cells, which helps in achieving a higher yield of the desired product.

Option B: This statement is also true. The most common type of bio-reactors used in industrial processes are of the stirred type, which have mechanical agitators to evenly distribute nutrients and maintain uniform conditions within the tank.

Option D: True, bio-reactors often include several essential systems: an agitator system for mixing, an oxygen delivery system to provide sufficient respiration for aerobic organisms, and a foam control system to prevent the formation of excessive foam, which could interfere with the operation of the reactor.

Thus, the incorrect statement about the typical scale and focus of bio-reactor use is Option C.

Correct answer is option (2), because

'X' which is ori is responsible for controlling the copy number of the linked DNA and 'Y' which is rop codes for protein involved in the replication of plasmid.

Options (1), (3) and (4) are incorrect as 'X' and 'Y' are not related to these functions.

Option A : Restriction enzymes

Restriction enzymes, also known as restriction endonucleases, act as molecular scissors in molecular biology. They recognize specific DNA sequences in a molecule and then cut the DNA at these recognition sites. Different restriction enzymes recognize and cut at different DNA sequences.

The correct answer is Option C.

The correct matching between List - I and List - II is as follows :

(A) Gene therapy - (IV) Allows correction of a gene defect.

Gene therapy is a technique that uses genes to treat or prevent disease by either replacing damaged genes with healthy ones, turning off harmful genes or introducing new genes to fight disease.

(B) RNA interference - (III) Cellular defence

RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression or translation, by neutralizing targeted mRNA molecules. This is a form of cellular defense.

(C) ELISA - (II) Diagnostic test for AIDS

ELISA, or enzyme-linked immunosorbent assay, is a commonly used laboratory test that measures the amounts of antibodies in the blood and can be used as a diagnostic test for AIDS.

(D) Gel Electrophoresis - (I) Separation of DNA fragments

Gel electrophoresis is a laboratory method used to separate mixtures of DNA, RNA, or proteins according to molecular size and charge.

Option (A) is the correct answer as, during isolation of the genetic material, purified DNA ultimately precipitates out after the addition of chilled ethanol.

Option (B) is not the answer as, proteins can be removed by treatment with proteases.

Option (D) is not the answer as RNA can be removed by treatment with ribonuclease.

Option (B) is the correct answer because in gene gun method, microparticles of tungsten or gold are used. Gold or tungsten are inert in nature so they do not alter the chemical composition of cells.

The correct answer is option (D) because recombinant DNA technology involves several steps in specific sequence such as isolation of DNA, fragmentation of DNA by restriction endonucleases, isolation of desired DNA fragment, ligation of the DNA fragment into a vector, transferring the recombinant DNA into the host, culturing the host cells in a medium at large scale and extraction of the desired product.

Option (c) is the correct answer because the first transgenic cow Rosie produced human protein-enriched milk. The milk contained the human alpha-lactalbumin and was nutritionally a more balanced product for human babies than natural cow milk.

Option (a) is not the correct answer because ADA deficiency in humans can be cured by gene therapy.

Option (b) is not the correct answer because transgenic sheep produced human $\alpha$-1-antitrypsin that is used to treat emphysema.

Option (d) is not the correct answer because insulin-like growth factor was not present in Rosie’s milk.

Option (b) is the correct answer as a palindromic DNA sequence is a DNA sequence of base pairs that reads same on the two strands when orientation of reading is kept the same. Out of the four options, option (b) is the only palindromic sequence.

5'GAATTC3'

3'CTTAAG5'

Option (d) is the correct answer as genetically engineered lymphocytes are not immortal cells and die after some time.

Option (c) is not the correct answer as the lymphocytes from patient's blood are grown in culture, outside the body but it is not the correct reason.

In option (b), if the gene isolated from bone marrow cells producing ADA is introduced into cells at early embryonic stages, it could be a permanent cure.

Option (b) is the correct answer as genetically engineered insulin has A-peptide and B-peptide chains of insulin which are produced separately in E.coli, then they are extracted and combined by creating disulphide bond between them.

Statement (a) is incorrect as genetically engineered insulin does not have an extra stretch of C-peptide. Statement (c) is incorrect as insulin obtained from cattles and pigs is not genetically engineered insulin. Statement (d) is incorrect because conversion of pro-insulin to insulin is not required during production of insulin by genetic engineering as A-peptide and B-peptide chains are produced separately. Statement (e) is incorrect as allergic reactions to insulin are mostly seen when the insulin is obtained from animals.