Downstream processing - class-XII

Description: downstream processing
Number of Questions: 15
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Tags: biotechnology and its application botany cell biology and biotechnology biology biotechnology: principles and processes
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After completion of the biosynthetic stage in the bioreactors, the product undergoes separation and purification processes, collectively termed as _______________.

  1. Transformation

  2. Electrophoresis

  3. Downstream processing

  4. Upstream processing

Correct Option: C

After the formation of the product in bioreactors, it undergoes through some processes before a finished product is ready for marketing. The processes include separation and purification of products which is collectively called as downstream processing.

So, the correct option is 'Option C'.

Bacteria genetically engineered to express a gene from a plant will

  1. Synthesise a protein with the same sequence of amino acids as in the plant and, therefore, the protein will have the same structure and function as in the plant.

  2. Synthesis a protein with essentially the same sequence of amino acids as in the plant with differences relating to different colon wobble rules between prokaryotes and eukaryotes

  3. Not be able to synthesise a protein due to the presence of exon splicing sequences in the DNA sequence from the plant

  4. Not be able to synthesise a protein because transaction is coupled with transaction and posttranscriptional processing does not occur in it.

Correct Option: A

When bacteria (a prokaryote) is engineered to express a gene from a plant (an eukaryote), a slightly  different approach is used. Eukaryotic genes have both exons and Introns which are transcribed into the primary transcript. Primary transcript is then processed by splicing (removal of introns and joining of exons), capping and tailling to produce functional mRNAs. This functional mRNA is then expressed into proteins. Prokaryotes lack such machinery, hence expression of an eukaryotic DNA becomes difficult in prokaryotic cells. Therefore, scientists prepare cDNA from the functional nRNA (without introns) using reverse transcriptase. This DNA is incorporated into bacteria (or another prokaryotic cell) for expression of plant gene. Such foreign gene synthesises a protein with the same sequence of amino acids as in the plant, and therefore the proteins have the same structure and function as in the plant.

So, the correct answer is 'Synthesise a protein with the same sequence of amino acids as in the plant and, therefore, the protein will have the same structure and function as in the plant.'

Animals that have their DNA manipulated to process and express a foreign gene are called

  1. Transgenic animals

  2. Somatic hybrids

  3. Somaclones

  4. Super animals

Correct Option: A

The animals which carry foreign genes are called transgenic animals. The foreign genes inserted into the genome of the animal using recombinant DNA technology are called transgenes.

Which one of the following acids was produced by fermentation process?

  1. Citric acid

  2. Lactic acid

  3. Acetic acid

  4. All of the above

Correct Option: D

Organic acids are among the most versatile ingredients in food and beverage industries. Citric acid, acetic acid, lactic acid, tartaric acid, malic acid, gluconic acid, propionic acid and fumaric acid are some of the organic acids used widely in various industries. They are obtained as the end-products or sometimes as the intermediate components of a particular biochemical cycle. Generally, organic acids are produced commercially either by chemical synthesis or fermentation. However, fermentation processes are the most commonly used method.

Thus, the correct answer is option D.

Purines possess nitrogen at

  1. 1, 2, 4 and 6 positions

  2. 1, 3, 5 and 7 positions

  3. 1, 3, 7 and 9 positions

  4. 1, 2, 6 and 8 positions

Correct Option: C

DNA fragments with sticky ends are not allowed to undergo self ligation by

  1. Unwindase

  2. Single strand binding proteins

  3. Gyrase

  4. Alkaline phosphatase

Correct Option: D
The correct option is D.
DNA fragment with sticky end are not allowed to undergo self ligation by Alkaline phosphatase. Alkaline phosphatase is a useful enzyme in genetic engineering, it remove $5'$ phosphase group from DNA and RNA fragments. It also removes the $5'$ phosphase groups from nucleotide and proteins.

In transgenics, the expression of transgene in the target tissue is known by

  1. Enhancer

  2. Transgene

  3. Promoter

  4. Reporter

Correct Option: D

Introduction of transgenes will result in

  1. Formation of a new species

  2. Formation of a new protein

  3. Alter a biosynthetic pathway

  4. Both B and C

Correct Option: D

Read statements a-d. Which of the following statements are incorrect?
a) First transgenic buffalo Rosie produced milk which was human alpha-lactalbumin enriched.
b) Restriction enzymes are used in isolation of DNA from other macromolecules.
c) Downstream processing is one of the steps of rDNA technology.
d) Disarmed pathogen vectors are also used in the transfer of rDNA into the host.

  1. b and c

  2. c and d

  3. a and c

  4. a and b

Correct Option: D

In insertional inactivation of $\beta$-galactosidase gene, the bacteria in white colonies have

  1. Nonrecombinant plasmid

  2. Recombinant plasmid

  3. No plasmid

  4. Linear foreign DNA

Correct Option: B

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

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
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

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

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

So, the correct option is 'Southern blotting'.

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