(3)

In bioreactors, large volumes (100–1000 litres) of bacterial culture can be processed.

(1)

In PCR, the repeated amplification is achieved by the use of a thermostable DNA polymerase enzyme Taq polymerase which is obtained from bacterium Thermus aquaticus. This enzyme remains active during the high temperature induced for denaturation of double stranded DNA.

(4)

(2)

(2)

A single PCR cycle involves three basic steps.
(i) Denaturation (DNA is heated to high temperature, usually 94°–96°C)
(ii) Primer annealing (two oligonucleotide primers anneal to each of the single stranded template DNA, temperature usually 40°–60°C) and
(iii) Extension (Taq DNA polymerase synthesises the DNA region between primers, optimum temperature 72°C).

(3)

(4)

Purification of isolated protein is one of the steps used in downstream processing of recombinant DNA technology.

(4)

In PCR, the repeated amplification is achieved by the use of a thermostable DNA polymerase, which remains active during the high temperature induced denaturation of double stranded DNA. So, if high temperature is not maintained, denaturation will be affected first as it is carried out at a higher temperature 94° to 96°C.

(2)

(3)

In order to cut the DNA with restriction enzymes, it needs to be in pure form, free from other macromolecules. Since the DNA is enclosed by the membranes, we have to break the cell open to release DNA and other macromolecules like RNA, proteins, polysaccharides and lipids. It is obtained by treating the bacterial cells/plant or animal tissue with enzymes. Other molecules are removed by appropriate treatments and purified DNA ultimately precipitates out after the addition of chilled ethanol.

(1)

(4)

A single PCR amplification cycle involves three basic steps, denaturation heating of target DNA to high temperature resulting in separation of two strands, annealing two oligonucleotide primers anneal or hybridise to each single template DNA and extension. Taq DNA polymerase synthesises DNA between primers and primers extend towards each other such that DNA stranded segment lying between the two is copied.

(1)

After the formation of the product in the bioreactor it undergoes some processes before a finished product is ready for marketing. The process includes separation and purification of products which are collectively called downstream processing.

(3)

A stirred-tank reactor is usually cylindrical or with a curved base to facilitate the mixing of the reactor contents. The stirrer facilitates, even mixing and oxygen availability throughout the bioreactor.

(4)

After the formation of the product in bioreactor, it undergoes some processes before a finished product to be ready for marketing. Downstream processing includes separation and purification process. The product obtained is subjected to quality control, testing and kept in suitable preservatives.

(3)

Taq polymerase, generally used in PCR is isolated from thermophilic bacterium Thermus aquaticus.

(4)

PCR is used only for amplification of DNA. It is not directly involved in Southern hybridisation technique.

(1)

Clonal propagation can be characterized by PCR and RAPD. The polymerase chain reaction (PCR) technique, generates microgram (µg) quantities of DNA copies (upto billion copies) of the desired DNA (or RNA) segment, present even as a single copy in the initial preparation, in a matter of few hours. RAPD stands for Random Amplification of Polymorphic DNA. It is a type of PCR, but the segments of DNA that are amplified are random. No knowledge of the DNA sequence for the targeted gene is required, as the primers will bind somewhere in the sequence, but it is not certain exactly where. Its resolving power is much lower than targeted, species specific DNA comparison methods, such as short tandem repeats.

(2)

PCR i.e., polymerase chain reaction amplifies DNA as per the equation $2^n$, where $‘n’$ refers to number of cycles. Thus, say, if 3 PCR cycles will run, then $2^3$ i.e., 2 × 2 × 2 $\Rightarrow$ 8 DNA fragments will be formed.

(4)

$\therefore$    Part labelled as C is foam breaker.