Tag: biotechnology: principles and processes

Questions Related to biotechnology: principles and processes

Which of the following is not component of downstream processing ____________.

  1. Expression

  2. Separation

  3. Purification

  4. Presentation


Correct Option: A

Which is not one of the major categories of biotechnology products ?

  1. Hormones and similar proteins

  2. Toxins for use in pest control

  3. DNA probes

  4. Vaccines


Correct Option: B
Explanation:

Biotechnology involves the exploitation of biological processes for industrial and other purposes, especially the genetic manipulation of microorganisms for the production of antibiotics, hormones, vaccines etc. It also involves various other methods involving production, amplification of DNA segments like DNA probe. 

Instead of production of toxins for use in pest control, biotechnology involves making plants resistant against pest by genetically engineering their genome. 
So, the correct option is 'Toxins for use in pest control'.

Which of the following is not a component of downstreaming processing?

  1. Separation

  2. Purification

  3. Preservation

  4. Expression


Correct Option: D
Explanation:
A widely recognized heuristic for categorizing downstream processing operations divides them into four groups which are applied in order to bring a product from its natural state as a component of a tissue, cell or fermentation broth through progressive improvements in purity and concentration.

Removal of insolubles is the first step and involves the capture of the product as a solute in a particulate-free liquid, for example the separation of cells, cell debris or other particulate matter from fermentation broth containing an antibiotic. Typical operations to achieve this are filtration, centrifugation, sedimentation, precipitation, flocculation, electro-precipitation, and gravity settling. Additional operations such as grinding, homogenization, or leaching, required to recover products from solid sources such as plant and animal tissues, are usually included in this group.

Product isolation is the removal of those components whose properties vary considerably from that of the desired product. For most products, water is the chief impurity and isolation steps are designed to remove most of it, reducing the volume of material to be handled and concentrating the product. Solvent extraction, adsorption, ultrafiltration, and precipitation are some of the unit operations involved.

Product purification is done to separate those contaminants that resemble the product very closely in physical and chemical properties. Consequently steps in this stage are expensive to carry out and require sensitive and sophisticated equipment. This stage contributes a significant fraction of the entire downstream processing expenditure. Examples of operations include affinity, size exclusion, reversed phase chromatography, ion-exchange chromatography, crystallization and fractional precipitation.

Product polishing describes the final processing steps which end with packaging of the product in a form that is stable, easily transportable and convenient. Crystallization, desiccation, lyophilization and spray drying are typical unit operations. Depending on the product and its intended use, polishing may also include operations to sterilize the product and remove or deactivate trace contaminants which might compromise product safety. Such operations might include the removal of viruses or depyrogenation.

So the correct option is 'Expression'.

Which among these is produced by distillation of fermented broth?

(i) Whisky (ii) Wine (iii) Beer (iv) Rum (v) Brandy

  1. (ii) and (iii) alone

  2. (i) and (ii) alone

  3. (iii) and (v) alone

  4. (i), (iv) and (v) alone

  5. (iii) and (iv) alone


Correct Option: D
Explanation:

Both wine and beer are essentially the products of the fermentation process - the fermented broth serves as the basis of the product. Other alcoholic beverages (whisky, rum, brandy) fall under the category of distilled spirits. Distillation is the process by which the alcohol is removed from the fermented broth (or wort) by heating the wort until the alcohol vaporizes, after which it is condensed. When almost pure alcohol is distilled from fermentation, the product is called as grain neutral spirits (GNS). 

Which of the following recent techniques is used for separating fragments of DNA?

  1. Eastern blotting

  2. Northern blotting

  3. Southern blotting

  4. Western blotting


Correct Option: C
Explanation:

Southern blotting involves DNA digestion, Gel electrophoresis, Blotting, Probe labeling, Hybridization and washing, and detection.

So, the correct option is 'Southern blotting'.

If a person obtains transformants by inserting a recombinant DNA within the coding sequence of enzyme -galactosidase, he will separate out recombinants from non-recombinants by which of the following observations?

  1. Non-recombinant colonies do not produce any colour whereas recombinants give blue coloured colonies

  2. Recombinant colonies do not produce any colour whereas non-recombinants give blue coloured colonies

  3. Recombinants and non-recombinants both produce blue coloured colonies

  4. No colonies are formed due to insertional inactivation


Correct Option: B
Explanation:

Alternative selectable markers have been developed which differentiate recombinants from the non-recombinants on the basis of their ability to produce colour in the presence of a chromogenic substrate. In this, a recombinant DNA is inserted within the coding sequence of an enzyme, ( -galactosidase. This results into inactivation of the enzyme, which is referred i to as insertional inactivation. The presence of a chromogenic j substrate gives blue coloured colonies if the plasmid in the bacteria does not have an insert. Presence of insert results into insertional inactivation of the -galactosidase and the colonies do not produce any colour, these are identified as recombinant colonies.

In the process of insertional inactivation ________________.

  1. A recombinant DNA is inserted within the coding sequence of enzyme -galactosidase, resulting in inactivation of the enzyme

  2. A recombinant DNA is inserted within the coding sequence of proteins involved in the replication of the plasmid

  3. A recombinant DNA is inserted within the recognition site for EcoRI

  4. None of the above


Correct Option: A
Explanation:

Alternative selectable markers have been developed which differentiate recombinants from the non-recombinants on the basis of their ability to produce colour in the presence of a chromogenic substrate. In this, a recombinant DNA is inserted within the coding sequence of an enzyme, ( -galactosidase. This results into inactivation of the enzyme, which is referred i to as insertional inactivation. The presence of a chromogenic j substrate gives blue coloured colonies if the plasmid in the bacteria does not have an insert. Presence of insert results into insertional inactivation of the -galactosidase and the colonies do not produce any colour, these are identified as recombinant colonies.

Statement 1 : In insertional inactivation, blue colour produced by bacterial colonies indicates that the plasmid does not have an insert into the bacterial genome. 
Statement 2: Presence of insert results into insertional inactivation of -galactosidase enzyme and the colonies do not produce any colour.

  1. Both statements 1 and 2 are correct

  2. Statement 1 is correct but statement 2 is incorrect

  3. Statement 1 is incorrect but statement 2 is correct

  4. Both statements 1 and 2 are incorrect


Correct Option: A
Explanation:

Selectable markers have been developed which differentiate recombinants from non- recombinants on the basis of their ability to produce colour in the presence of a chromogenic substrate. In this, a recombinant DNA is inserted within the coding sequence of an enzyme B-galactosidase. This results into an  insertional inactivation. The presence of chromogenic substrate gives blue coloured colonies if the plasmid in bacteria does not have an insert. Presence of insert results into insertional inactivation of a^-galactosidase enzyme and the colonies do not produce any colour, these are identified as recombinant colonies. 

So, the correct option is 'Option A' .

Direct visual selection method for the selection of recombinant host cells on the basis of their inability to produce colour in the presence of chromogenic substrate can be applied if the vector used is a

  1. Modified plasmid vector of E.coli

  2. Modified bacteriophage

  3. Modified Agrobacterium tumifaciens plasmid

  4. Disarmed retroviruse


Correct Option: A

During isolation of genetic material, the chemical used to precipitate out the purified DNA is

  1. Bromophenol blue

  2. Chilled ethanol

  3. Ethidium bromide

  4. Both A and C


Correct Option: B
Explanation:
The purified DNA, after treatment with various enzymes, precipitates out after addition of chilled ethanol. This is viewed as a collection of fine threads in the suspension, and is easily collected. The process is known as DNA spooling.
So, the correct answer is 'Chilled ethanol'.