Question 1

The restriction enzymes are used in genetic engineering, because

Accepted Answer

The restriction enzymes are obtained from some bacteria. They are also called endonuclease, that can cut a specific DNA and leaves the molecule.

Question 2

Recombinant DNA is achieved by cleaving the pro-DNAs by

Accepted Answer

Restriction endonucleases are enzymes that are specialised to cut DNA at specific sites in the regions having palindromic sequences.

Question 3

Restriction endonucleases are

Accepted Answer

Restriction endonuclease cuts DNA at very specific site and in used genetic engineering.

Question 4

In genetic engineering, the antibiotics are used :

Accepted Answer

Antibiotics medium are used to mark or select transformant & Recombinant bacteria so we can say antibiotics used as a selectable markers with marker gene (Antibiotics resistant gene).

Question 5

Most extensively studied bacterium is :

Accepted Answer

Most extensively studied bacterium in Escherichia coli (E. coli) which commonly found in intestine of man and cattles as endosymbiont. Rarely it becomes pathogenic and causes Urinary Tract Infection E. coli has been used extensively in molecular biology and biotechnology. Semiconservative type DNA replication was first demonstrated in E. coli. Restriction endonuclease 'Eco R-I and Eco R-II' have been isolated from the cells of E. coli. Plasmids of E. coli. First human insulin and human growth hormone somatotropin were synthesized with the help of E. coli.

Question 6

Auxotrophs are:

Accepted Answer

Auxotrophs are mutants of bacterial strains lacking one or more essential genes required to synthesize amino acids during protein synthesis, They are, therefore incapable of growing on the basal medium and need special media supplemented with desired amino acid/s Mutants can be converted to normal strains (prototrophs) either through genetic recombination. Sexuality in E. coli has been studied using its auxotrophs of different deficiencies.

Question 7

Hydrocarbon digesting plasmids are found in :

Accepted Answer

Usually the complex hydrocarbons are nonbiodegradable but the plasmids of Pseudomonas putida have shown their capacity of digesting the complex hydrocarbons. Several strains of Pseudomonas putida were used to develop a superbug which can digest all types of simple or complex hydrocarbons found in crude petroleum. Superbug has the capacity of controlling oil pollution in ocean due to leakage of oil tankers filled with crude petroleum.

Question 8

A probe which is a molecule used to locate specific sequences in a mixture of DNA or RNA molecules could be:

Accepted Answer

The molecular probes are usually single stranded pieces of DNAs (sometimes RNAs) labeled with radio isotopes such as phosphorus-32. Molecular probes are available for many genetic disorder such as Duchenne muscular dystrophy, cystic fibrosis, Tay-Sachs disease.

Question 9

A foreign DNA and plasmid cut by the same restriction endonuclease can be joined to form a recombinant plasmid using

Accepted Answer

Ligase is a class of enzymes that catalyse the formation of covalent bonds using the energy released by the cleavage of ATP. Ligases are important in the synthesis and repair of many biological molecules, including to insert foreign DNA into cloning vectors.

Question 10

A gene whose expression helps to identify transformed cell is known as

Accepted Answer

Some genes called "selectable markers" help in selecting those host cells which contain the vectors (transformants) and eliminating the non-transformants.

Question 11

The DNA fragments separated on an agarose gel can be visualised after staining with :

Accepted Answer

The separated DNA fragments can be seen only after staining them with a compound known as ethidium bromide (EtBr) followed by exposure to UV radiation as bright orange coloured bands.

Question 12

Following statements describe the characteristics of the enzyme Restriction Endonuclease. Identify the incorrect statement.

Accepted Answer

Restriction endonucleases are enzymes that recognize a specific DNA sequence, called a restriction site, and cleave the DNA within or adjacent to that site. This enzyme binds DNA at specific sites and cut both the strands by breaking phosphodiester linkage.

Question 13

Identify the wrong statement with regard to Restriction Enzymes.

Accepted Answer

Restriction enzymes, also called restriction endonucleases, cut double stranded DNA molecules by cleaving phosphodiester bonds at palindromic sequences. This means that the majority of the restriction enzymes cut the DNA into a fragments that are characterized by a twofold rotational symmetry.

Question 14

Read the following four statements (I-IV) about certain mistakes in two of themI. the first transgenic buffalo, Rosie produced milk which was human alpha-lactalbumin enriched.II. restriction enzymes are used in isolation of DNA from other macromolecules.III. downstream processing is one of the steps of R-DNA technology.IV disarmed pathogen vectors are also used in transfer of R-DNA into the host.Which are the two statements having mistakes?

Accepted Answer

Transgenic Rosie is first transgenic cow produced in 1997.Restriction enzymes cut the DNA at specific site. The separation of DNA is performed by gel electrophoresis.

Question 15

A single strand of nucleic acid tagged with a radioactive molecule is called

Accepted Answer

Probes are 15-30 bases long radioactive labelled oligonucleotides (RNA or DNA) used to detect complementary nucleotide sequences, used for disease diagnosis, etc.

Question 16

The figure below is the diagrammatic representation of the E. coli vector pBR322. Which one of the given options correctly identifies its certain components (s)?

Accepted Answer

Ori represents the site of origin of replication, rop represents the proteins that take part in the replication. Hind III, Eco RI are the recognition sites of restriction endonucleases. ampR and tet R are the antibiotic resistant gene parts.

Question 17

DNA fragments generated by the restriction endonucleases in a chemical reaction can be separated by :

Accepted Answer

DNA fragment generated by restriction endonuclease is separated by Gel electrophoresis.

Question 18

The colonies of recombinant bacteria appear white in contrast to blue colonies of non-recombinant bacteria because of :

Accepted Answer

Lac operon Z-gene produce beta galactosidase that convert X-gal chromogen into blue colour in non recombinant bacteria if this gene is affected by insertion inactivation this reaction does not take place and bacteria appears white. But this inactivation take place in beta galactosidase gene not in α-galactosidase gene in recombinant bacteria so right answer is non recombinant bacteria containing beta galactosidase enzyme that cause blue colour colonies of bacteria.

Question 19

Stirred-tank bioreactors have been designed for -

Accepted Answer

∙ The use of stirred tank bioreactors is to provide aeration in the culture media. There are large blades that keep rotating inside the culture.∙ Due to the movement of the blades, the air gets to mix with the culture leading to proper aeration. ∙ The availability of more air in the culture increases the availability of oxygen for the given biochemical process.

Question 20

A foreign DNA and plasmid cut by the same restriction endonuclease can be joined to form a recombinant plasmid using

Accepted Answer

A foreign DNA and plasmid cut by the same restriction endonuclease can be joined to form a recombinant plasmid using ligase.

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Solutions for Biology-for-NEET-Volume-2-Class-XII by Career Point, Biotechnology: Principles and Processes

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