Test: Biotechnological Applications in Medicine (NCERT) - NEET MCQ

Human insulin is made up of 51 amino acids arranged in two polypeptide chains: A, having 21 amino acids and B, with 30 amino acids. The two polypeptide chains are interconnected by two disulphide bridges.

Topic in NCERT: Genetically engineered insulin

Line in NCERT: "insulin consists of two short polypeptide chains: chain a and chain b, that are linked together by disulphide bridges."

Gene therapy is a technique for correcting defective genes responsible for disease development. Under intensive investigation are, disease ranging from the rare genetic diseases caused by single mutations like sickle cell anaemia to killer diseases such as server combined immuno-deficiency (SCID). The first clinical gene therapy was given in 1990 to a 4-years old girl with adenosine deaminase (ADA) deficiency. This enzymes is very important for the immune system to function. ADA deficiency can lead to severe combined immuno-deficiency (SCID).

Topic in NCERT: Gene therapy

Line in NCERT: "gene therapy is a collection of methods that allows correction of a gene defect that has been diagnosed in a child/embryo. here genes are inserted into a person's cells and tissues to treat a disease."
"the first clinical gene therapy was given in 1990 to a 4-year old girl with adenosine deaminase (ada) deficiency."

Recombinant DNA is a form of DNA whose nucleotide sequence has undergone alteration as a result of incorporation of exchange with another DNA strand. In recombinant DNA technology, human genes are often transferred into bacteria or yeast because both bacteria and yeast multiply very fast to form huge population, which expresses the desired gene. By doing so, one can observe the phenotypes of the gene more quickly and in a larger scale than by studying the same traist in humans.

Topic in NCERT: Biotechnological applications in agriculture

Line in NCERT: "recombinant dna technology has made it possible to engineer microbes, plants and animals such that they have novel capabilities."

The technique of polymerase chain reaction (PCR) has been applied to detect HIV in suspects AIDS patients and to detect mutations in genes in suspected cancer patients.

Topic in NCERT: Molecular diagnosis

Line in NCERT: "very low concentration of a bacteria or virus (at a time when the symptoms of the disease are not yet visible) can be detected by amplification of their nucleic acid by pcr."

A represents polypeptide chain C which is removed prior to insulin formation

Topic in NCERT: Genetically engineered insulin

Line in NCERT: "insulin consists of two short polypeptide chains: chain a and chain b, that are linked together by disulphide bridges."

Using conventional methods of diagnosis (serum and urine analysis, etc.) early detection is not possible. Recombinant DNA technology, Polymerase Chain Reaction (PCR) and Enzyme Linked Immuno-sorbent Assay (ELISA) are some of the techniques that serve the purpose of early diagnosis.

Topic in NCERT: Molecular diagnosis

Line in NCERT: "recombinant dna technology, polymerase chain reaction (pcr) and enzyme linked immuno-sorbent assay (elisa) are some of the techniques that serve the purpose of early diagnosis."

A single stranded DNA or RNA joined with a radioactive molecule (probe) is allowed to hybridise to its complementary DNA in a clone of cells. It is followed by detection using autoradiography. The clone having the mutated gene will not appear on the photographic film, because the probe will not have the complementarity with the mutated gene. 

Topic in NCERT: Molecular diagnosis

Line in NCERT: "a single stranded dna or rna, tagged with a radioactive molecule (probe) is allowed to hybridise to its complementary dna in a clone of cells followed by detection using autoradiography."

Gene therapy is a newly emerging branch of biotechnology with tremendous results. It is basically used for correcting genetic disorders. In gene therapy, normal genes are introduced in the cells to replace the missing genes or defective genes. 
Early gene therapy has been proved to be more effective in treating certain brain diseases in humans. They have also shown exemplary results in mice.  
When a child is born, he has its innate immunity, which does not allow any foreign body to settle into its own body easily. But before birth, it has not yet recognized itself, so therapy would be easily accepted.

Topic in NCERT: Gene therapy

Line in NCERT: "if the gene isolate from marrow cells producing ada is introduced into cells at early embryonic stages, it could be a permanent cure."

In 1983, Eli Lilly an American company, first prepared two DNA sequences corresponding to A and B chains of human insulin and introduced them in plasmids of Escherichia coli to produce insulin chains. Chains A and B were produced separately, extracted and combined by creating disulphide bonds to form human insulin (humulin).

Topic in NCERT: Genetically engineered insulin

Line in NCERT: "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 to produce insulin chains."

As a first step towards gene therapy, lymphocytes from the blood of the patient are grown in a culture outside the body. A functional ADA−cDNA (using a retroviral vector) is then introduced into these lymphocytes, which are subsequently returned to the body of the patient. However, as these cells are not immortal, the patient requires periodic infusion of such genetically engineered lymphocytes.

Topic in NCERT: Gene therapy

Line in NCERT: "however, as these cells are not immortal, the patient requires periodic infusion of such genetically engineered lymphocytes."

Gene therapy is a collection of methods, that allows correction of gene defect that has been diagnosed in a child/embryo. Correcting of a genetic defect involves delivery of a normal gene into the individual or embryo to take over the function of and compensate for the non-functional gene.

Topic in NCERT: Gene therapy

Line in NCERT: "gene therapy is the insertion of genes into an individual's cells and tissues to treat diseases especially hereditary diseases."

For effective treatment of a disease, early diagnosis and understanding its pathophysiology is very important. Using conventional methods of diagnosis (serum and urine analysis, etc.), early detection is not possible. Recombinant DNA technology, Polymerase Chain Reaction (PCR) and Enzyme Linked Immuno-sorbent Assay (ELISA) are some of the techniques that serve the purpose of early diagnosis.

Topic in NCERT: Molecular diagnosis

Line in NCERT: "you know that for effective treatment of a disease, early diagnosis and understanding its pathophysiology is very important."

The correct sequence is
1.Synthesis of the gene for human insulin artificially.
2.Insertion of human insulin.
3.Introduction of recombinant plasmid into E.coli
4. Culturing recombinant E.coli in bioreactors.
5.Extraction of a recombinant gene product from E.
6.Purification of Humulin.
So, the correct option is 'i, iv, v, ii, vi, iii'.

Topic in NCERT: Genetically engineered insulin

Line in NCERT: "chains a and b were produced separately, extracted and combined by creating disulfide bonds to form human insulin."

Proinsulin is a single polypeptide chain composed of the B and A subunits of insulin joined by the C-peptide region. Proinsulin is converted to insulin during the maturation of secretory vesicles by the action of enzymes.

Topic in NCERT: Proinsulin

Line in NCERT: "this c peptide is not present in the mature insulin and is removed during maturation into insulin."

Very low count of bacteria or viruses (when the symptoms of the disease are not yet visible) cab be detected by multiplication of their nucletic acid by PCR (PCR can detect very low amounts of DNA). PCR is usually used to detect HIV in suspected AIDS patients.

Topic in NCERT: Molecular diagnosis

Line in NCERT: "pcr is now routinely used to detect hiv in suspected aids patients."