BIOLOGY M.C.Q (1 Marks)

1. Genetic engineering.

2. A continuous culture system.

4. It is isolated from viruses.

1. Origin of replication (ori).

Origin of replication is a sequence from where replication starts and any piece of DNA when linked to this sequence can be made to replicate within the host cells. This sequence is also responsible for controlling the copy number of the linked DNA. So, if one wants to recover many copies of the target DNA it should be cloned in a vector whose origin support high copy number.

2. Coli.

1. Southern transfer

Explanation:

Southern Transfer is the process developed by Southern to transfer the DNA bands from agarose gel to nitrocellulose membrane in order to obtain a autoradiograph and visualize the bands under X ray.

3. Microscopic pellets

Explanation:

In the gene gun method, microscopic pellets of gold or tungsten are coated with the transgene fragments and shot into the plant cells or tissues at high velocity.

3. 1.0 billion

Explanation:

The Polymerase chain reaction (PCR) is a method widely used in molecular biology to make many copies of a specific DNA segment. Using PCR, a single copy (or more) of a DNA sequence is exponentially amplified to generate thousands to millions of more copies of that particular DNA segment. The number of double-stranded DNA pieces is doubled in each cycle so that after n cycles we have 2^n (2 to the n: the power) copies of DNA. The cycle is usually repeated 30 times and 1 billion copies are made at the end of 30 PCR cycles.

3. Increase efficiency with which DNA enters the bacterium.

4. All of these

Explanation:

Application of biotechnology occurs in agriculture, biomedicine and environmental field.

3. Both A and B

4. Prokaryotes

Explanation:

The bacteria (prokaryotes) contain special types of enzymes called the restriction enzymes.

 These enzymes are responsible for cleaving the viral DNA that enters the bacterial cell for the infection, thereby restricting the growth of the virus particles. 

Therefore, these are nucleases. 

These do not degrade the DNA of the bacterial cell because the DNA is protected by methylation. 

Due to their specific cleaving activity, the restriction enzymes are widely used in rDNA technology.

2. Exonuclease.

Exonucleases remove nucleotides from the ends of the DNA whereas endonucleases make cuts at specific positions within the DNA.

1. Extension of primer end on the template DNA.

1. Thermus aquaticus

Explanation:

Taq polymerase is a thermostable DNA polymerase I obtained from the thermophilic bacterium Thermus aquaticus.

3. Endonuclease

Explanation:

Endonucleases are the enzymes which cleave the phosphodiester bonds in the internal regions of the polynucleotide chain (DNA or RNA). The exonucleases cleave the polynucleotide chains from one end. While the protease cleaves the proteins the lipases act on the lipids.

1. Thermus aquaticus.

2. Restriction enzymes

Explanation:

Genetic engineering is possible because of special enzymes that cut DNA. These enzymes are called restriction enzymes or restriction endonucleases. Restriction enzymes are proteins produced by bacteria to prevent or restrict invasion by foreign DNA. They act as DNA scissors, cutting the foreign DNA into pieces so that it cannot function. These enzymes are routinely used for DNA modification in laboratories and are a vital tool in molecular cloning

4. Polymerase chain reaction

Explanation:

Polymerase chain reaction (PCR) is a method used to rapidly make millions to billions of copies of a specific DNA sample, not the method to transfer DNA to the host cell.

3. Extension of primer end on the template DNA.

Taq polymerase is used between annealing and extension, help in extension of primer end on the template DNA.

3. Control dissolved oxygen

Explanation:

Stirred tank fermenter bioreactors (STBRs) are the reactors most widely employed for culturing of biological agents such as cells, enzymes, or antibodies. They are contractors where the well-mixed among phases is obtained mainly by internal mechanical agitation. It does not control dissolved oxygen.

3. Entamoeba coli.

Entamoeba coli is not a bacterium and Haemophilus influenzae, Escherichia coli and Bacillius quifacieus are source of restriction endonuclease.

3. Golden Rice.

3. Any DNA fragment

Explanation:

Restriction enzymes, also called restriction endonucleases, bind to DNA and cleave the double strand, forming smaller pieces of DNA. There are three types of restriction enzymes; Type I restriction enzymes recognize a DNA sequence and cut the strand randomly more than one thousand base pairs away from the site. Type II restriction enzymes, the most useful for molecular biology laboratories, recognize and cut the DNA strand predictably at a specific sequence which is usually less than ten base pairs long. Type III restriction enzymes are similar to Type I, but these cut the DNA about thirty base pairs from the recognition sequence.

4. Restriction endonucleases purified from bacteria can be used in vitro.

2. A bacterium

4. Selectable marker.

2. Required for PCR

Explanation:

Like DNA replication in an organism, PCR requires a DNA polymerase enzyme that makes new strands of DNA, using existing strands as templates. The DNA polymerase typically used in PCR is called Taq polymerase, after the heat-tolerant bacterium from which it was isolated (Thermus aquaticus).

1. Extrachromosomal material.

3. Molecular knives for cutting DNA at specific sites

Explanation:

Restriction endonucleases are enzymes that cleave the sugar-phosphate backbone of DNA. In most practical settings, a given enzyme cuts both strands of duplex DNA within a stretch of just a few bases. Several thousand different restriction endonucleases have been isolated, which collectively exhibit a few hundred different sequence (substrate) specificities.

4. 5'-GAATTC-3' 3'-CTTAAG-5'

4. Transduction

2. Palindromic sequences

Explanation:

Restriction enzymes can cut at specific sites which resemble palindrome in nature having palindromic DNA sequences ( GAATTC-CTTAAG).

3. Gene transfer without a vector

Explanation:

Polyethylene glycol (PEG) is a polyether compound. The compound has varied applications. Its biological uses include being used as a precipitant for plasmid DNA isolation and protein crystallisation. PEG is also used as a fusing agent in the transformation experiments. The gene or the desired fragment of DNA can be transferred into the host cell without the use of vector. PEG with calcium ions allows the membrane to become charged and allow the entry of the gene.

2. Bacterial gene.

3. It is isolated from viruses.

Restriction enzyme:

• Recognises a palindromic nucleotide sequence.
• Is an endonuclease isolated from bacteria.
• Produces the same kind of sticky ends in different DNA molecules.

1. Fragment of DNA which acts as vector.

3. Extension of primer end on template DNA

Explanation:

PCR is the short form for polymerase chain reaction which is the phenomenon which is used for amplification of the part-specific region of DNA as per our interest. Taq polymerase is the enzyme that attaches nucleotides together and help is the extension of primer end on the template DNA.

3. Karry Mullis

Explanation:

Kary Mullis. Kary Banks Mullis (born December 28, 1944) is a Nobel Prize-winning American biochemist. In recognition of his invention of the polymerase chain reaction (PCR) technique, he shared the 1993 Nobel Prize in Chemistry with Michael Smith and earned the Japan Prize in the same year.

So, the correct answer is 'Karry Mullis.'

2. A somatic plant cell can grow into a complete plant

Explanation:

Plants have the ability to grow into a complete plant from a single cell. While animals are only produced by their species and reproduction. Hence, they are more readily manipulated by genetic engineering than an animal. 

1. DNA amplification

Explanation:

Polymerase chain reaction ( PCR), a technique used to make numerous copies of a specific segment of DNA quickly and accurately.

3. A continuous culture system.

• After having cloned the gene of interest and having optimised the conditions to induce the expression of the target protein one has to consider producing it on a large scale. Small volume cultures cannot yield appreciable quantities of products.
• To produce in large quantities the development of bioreactors, where large volume (100-1000 litres) of culture (continuous) can be processed, was required.

3. Nematodes.

2. Probe

1. Both assertion and reason are true and reason is the correct explanation of assertion.

1. Introducing rDNA into plant cells.

4. Restriction endonuclease

Explanation:

A restriction enzyme, restriction endonuclease is an enzyme that cleaves DNA into fragments at or near specific recognition sites within molecules known as restriction sites. In the bacterial cell, restriction enzymes cleave foreign DNA, thus eliminating infecting organisms.

3. Nucleases

2. Extra-chromosomal DNA, which can self replicate.

1. Lucknow

Explanation:

Central Drug Research Institute (CDRI) is one of the first laboratories established after independence in the year 1951. It is a multidisciplinary institute that works on synthesis, screening, development studies and clinical studies among others. It has developed around 12 drugs of which, Arteether (Brand name=E-mal) active against falciparum malaria and Centchroman (Brand name=Sah, a birth control contraceptive pill are developed.