2nd PUC Biology Question Bank Chapter 11 Biotechnology: Principles and Processes

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Karnataka 2nd PUC Biology Question Bank Chapter 11 Biotechnology: Principles and Processes

2nd PUC Biology Biotechnology: Principles and Processes NCERT Text Book Questions and Answers

Question 1.
Can you list 10 recombinant proteins which are used in medical practice? Find out where they are used as therapeutics (use the internet).
Answer:
Recombinant proteins used in medical practice as therapeutics are as follows:

  • OKT-3, a therapeutic antibody is used for the reversal of acute kidney transplantation rejection.
  • ReoPro is for the prevention of blood clots.
  • Tissue plasminogen activator (TPA) is for acute myocardial infarction.
  • Asparaginase is for the treatment of some types of cancer.
  • DNase is for the treatment of cystic fibrosis.
  • Insulin is used in diabetes mellitus.
  • Blood clotting factor VIII is used for the treatment of haemophilia A.
  • Blood clotting factor IX is for the treatment of haemophilia B.
  • Hepatitis B vaccine is for the prevention of hepatitis B.
  • Platelet-derived growth factor has been approved for diabetic/skin ulcers. It also stimulates wound healing.

Question 2.
Make a chart (with diagrammatic representation) showing a restriction enzyme, the substrate. DNA on which it acts, the site at which it cuts DNA, and the product it produces.
Answer:

2nd PUC Biology Question Bank Chapter 11 Biotechnology Principles and Processes 1

Question 3.
From what you have learned, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?
Answer:
Human cells vary in size and volume. DNA is fixed in its size. That makes it kind of hard (like impossible) to state a concentration for DNA. Only a range can be given, and that information has little to no practical value and even less meaning.

Question 4.
What would be the molar concentration of human DNA in a human cell? Consult your teacher.
Answer:
Molar concentration is the ratio of the number of moles of solute in a solution divided by the volume of the solution expressed in liters.
The average weight of a DNA basepair = 650 daltons (1 dalton equals the mass of a single hydrogen atom or 1.67 x 10-24 grams)
The molecular weight of a double-stranded
DNA molecule = Total no. of basepairs x 650 daltons
The human genome is 3.3 x 109 bp in length.
Hence, the weight of human genome,
= 3.3 x 109 bp x 650 Da
= 3.59 x 10-12 gm.
The molar concentration of DNA can be calculated accordingly.

Question 5.
Do eukaryotic cells have restriction endonucleases? Justify your answer.
Answer:
The stirred tank bioreactor facilitates the mixing and oxygen availability. It controls the temperature and pH inside the bioreactor.

KSEEB Solutions

Question 6.
Besides better aeration and mixing properties, what other advantages do stirred tank bioreactors to have over shake flasks?
Answer:
Shake flasks are used for growing and mixing the desired materials on a small scale in the laboratory. Bioreactors are vessels in which raw materials are biologically converted into specific products by microbes, plant and animal cells, and their enzymes. Bioreactors are used for large-scale production of biomass or sell products under aseptic conditions. Here large volumes (100-1000 litres) of culture can be processed. A bioreactor provides the optimal conditions for achieving the desired product by providing optimum growth conditions (temperature, pH, substrate, salts, vitamins, oxygen). The most commonly used bioreactors are of stirring type.

A bioreactor is more advantageous than shake flasks. It has an agitator system to mix the contents properly, an oxygen delivery system to make available of oxygen, a foam control system, a temperature control system, a pH control system, and a sampling port to withdraw the small volumes of the culture periodically.

Question 7.
Collect 4 examples of palindromic DNA sequences by consulting your teacher. Better try to create a palindromic sequence by following base-pair rules.
Answer:
2nd PUC Biology Question Bank Chapter 11 Biotechnology Principles and Processes 2

Question 8.
Can you recall meiosis and indicate at what stage recombinant DNA is made?
Answer:
Meiosis I – Pachytene – When recombination nodule appears after synaptonemal complex formation.

Question 9.
Can you think and answer how a reporter enzyme can be used to monitor the transformation of host cells by foreign DNA in addition to a selectable marker? Ans: A selectable marker helps to identify transformed host cells and non transformed cells will be eliminated and only transformed cells will grow. Whereas reporter gene is the one whose phenotypic expression can be monitored and thus it reports about activity or change in advance of the effect of the modification, in addition to eliminating non transformed cells by selectable markers. HLDescribe briefly the followings:
(a) Origin of replication
(b) Bioreactors
(c) Downstream processing
Answer:
(a) Origin of replication (on): One of the major components of a plasmid is a sequence of bases where replication starts. It is called the origin of replication (on). This is a specific portion of the plasmid genome that serves as a start signal for self-replication (to make another copy of itself). Any piece of DNA when linked to this sequence can be made to replicate within the host cells. This property is used to make a number of copies of linked DNA (or DNA insert).

(b) Bioreactors: These are vessels in which raw materials are biologically converted into specific products by microbes, plant and animal cells, and their enzymes. They are allowed to synthesise the desired proteins which are finally extracted and purified from cultures. Small volume cultures are usually employed in laboratories for research and production of fewer quantities of products. However, large-scale production of the products is carried out in bioreactors’. The most commonly used bioreactors is a stirring type bioreactor (fermenter) that has a provision for batch culture or continuous culture.

(c) Downstream processing: After the formation of the product in the bioreactors, it undergoes some processes before a finished product is ready for marketing. These processes include separation and purification of products which are collectively called downstream processing. The product is then subjected to quality control testing and kept in suitable preservatives. The downstream process and quality control test are different for different products

Question 11.
Explain briefly
(a) PCR
(b) Restriction enzymes and DNA
(c) Chitinase
Answer:
a. The in vitro amplification of DNA by repeated cycles of strand separation and polymerisation is PCR.
b. The nuclease enzyme that cuts the DNA at a unique sequence is called restriction endonuclease. They are also known as molecular knives, molecular scissors, or molecular scalpels.
c. Chitinase is digestive enzymes that break down glycosidic bones in chi tin.

Question 12.
Discuss with your teacher and find out how to distinguish between
(a) Plasmid DNA and Chromosomal DNA
(b) RNA and DNA
(c) Exonuclease and Endonuclease
Answer:

(a) Plasmid DNA and Chromosomal DNA

Plasmid DNA Chromosomal DNA
(i) It is extranuclear DNA It is nuclear DNA
(ii) It caries nonvital genes It possesses vital genes
(iii) A bacterial cell may carry one to several plasmid DNAs. A bacterial cell carries only one chromosome DNA

(b) RNA and DNA

RNA DNA
(i) It is ribonucleic acid Deqxy ribonucleic acid
(ii) It is single strandred Double standard
(iii) RNA produced from DNA template Parental DNA acts as a DNA template
(iv) Nitrogen base Uracil is present instead of thymine, which pairs with adenine. Thymine pairs with adenine

(c) Exonuclease and Endonuclease

Exonuclease Endonuclease
(i) It breaks DNA from ends It cuts DNA from inside
(ii) The separated fragments are small nucleotides These separated fragments  are generally large sized
(iii) The separated fragments cannot be used in genetic engineering The desirable separated fragments are used in genetic engineering

2nd PUC Biology Biotechnology: Principles and Processes Additional Questions and Answers

2nd PUC Biology Biotechnology: Principles and Processes One Mark Question

Question 1.
By observing the given pair fill-up the blanks

  1. Cutting DNA : Restriction endonuclease :: Joining DNA : …………………….
  2. Chitinase : Fungus :: Cellulose : ………………………..
  3. Protein : Protease :: RNA : …………………………

Answer:

  1. DNA ligase
  2. Plant cells
  3. Ribonuclease

Question. 2.
Which DNA polymerase is active in high temperatures?
Answer:
Taq DNA polymerase is active at high temperatures.

Question 3.
Restriction endonucleases are used to cut DNA at specific sites.. Name the first endonuclease isolated from Escherichia coli.
Answer:
EcoRI

KSEEB Solutions

Question. 4.
Write the full form of PCR. Which enzyme is used in?
Answer:
Polymerase Chain Reaction (PCR).
Taq DNA is used in PCR.

Question 5.
Name the technique used for separating DNA fragments in the laboratory
Answer:
Electrophoresis. (Dehli 2005)

Question. 6.
First recombinant DNA was formed in.
Answer:
In Bacteria Salmonella Typhimurium.

Question 7.
Write the function of the restriction enzyme in a bacterial cell?
Answer:
Responsible for restricting the growth of bacteriophage.

Question. 8.
Where does Hind II cut the DNA molecule?
Answer:
It cuts the DNA molecule at a specific 6 base pair seQuestionuence.

Question 9.
Why are plasmids and bacteriophages commonly used as cloning vectors?
Answer:
Plasmids and bacteriophages have the ability to replicate within bacterial cells independently of the chromosomal DNA.

Question. 10.
Which type of charge found in DNA?
Answer:
Negative charge.

Question 11.
What is downstream processing?
Answer:
Downstream processing is the recovery of product from the fully grown genetically modified cells, its purification and preservation

Question. 12.
What is electrophoresis?
Answer:
Electrophoresis is a techniQuestionue used in laboratories in order to separate macromolecules based on size.

Question 13.
What is gene therapy?
Answer:
It is the replacement of a defective gene by normal healthy and functional gene. This method helps to overcome the effect of various disorders like sickle cell anaemia, alkaptonuria, SCID, colour blindness etc.

Question. 14.
Name the technique in which we should be isolated the DNA segment.
Answer:
Electrophoresis.

Question 15.
What is amplification?
Answer:
It is the process of making multiple copies of gene/DNA segments of interest.

Question 16.
What is recombinant protein?
Answer:
It is a biochemical compound or useful protein produced inside the heterologous host cell by recombinant biotechnology method.

Question 17.
What is a bioreactor or fermenter?
Answer:
It is a container in which the biochemical process is carried out by using living cells and their growth medium.

Question 18.
What meant by bioconversion?
Answer:
It is the process by which raw materials are biologically converted into specific products using microbes, plant or animal cells and or their enzymes.

Question 19.
Why are antibiotic resistance genes used as selectable markers for E.Coli?
Answer:
Since E.Coli doesn’t have any of antibiotic resistance genes, antibiotic resistance genes are used from outside as selectable marker.

2nd PUC Biology Biotechnology: Principles and Processes Two Marks Questions

Question 1.
Name the scientists who constructed recombinant DNA. Name the bacterium from which they isolated the gene.
Answer:
Stanley Cohen and Herbert Boyer were the first to construct recombinant DNA. They isolated the gene from the bacterium. Salmonella typhimurium.

Question 2.
Few gaps have been left in the following table showing certain terms and their meanings, fill up the gaps.
Term Meanings
(i) ………….. Non-coding sequence in eukaryotic DNA
(ii) ………….. The technique used in solving paternity disputes
(iii) Restriction endonuclease …………..
(iv) Plasmids …………..
(v) Transgenics …………..
(vi) Nucleotide sequences with single base deficiencies …………….

KSEEB Solutions

Question 3.
Name the particular technique in biotechnology whose steps are shown in the figure use the figure to summarize the technique in three steps.
Answer:

  • Template stand
  • DNA fingerprinting
  • Extranuclear DNAs
  • Organisms having genes of other organisms obtained through genetic engineering.
  • Single nucleotide polymorphism. (SNPs)

Question 3.
Name the particular technique in biotechnology whose steps are shown in the figure use the figure to summarize the technique in three steps.
Answer:
2nd PUC Biology Question Bank Chapter 11 Biotechnology Principles and Processes 3
(a) Recombinant technology
(b)

  • Cutting and isolation of human gene
  • Incorporation of human gene into the plasmid to produce recombinant DNA or plasmid
  • Incorporation of recombinant plasmids into bacterium to obtain gene product

Question 4.
Refer to the diagram and answer the following:
(i) From what T1– plasmid is obtained?
(ii) Name the enzyme which is involved in step I
(iii) What happens in step II
(iv) The plant produced is called hybrid or transgenic
(v) Will the plant produced have other genes along with desired genes? Yes or No explain.
Answer:
2nd PUC Biology Question Bank Chapter 11 Biotechnology Principles and Processes 4
(i) Agrobacterium tumefaciens
(ii) Restriction endonuclease
(iii) Incorporation of genes in T1 plasmid in the region of T-DNA.
(iv) Transgenic
(v) Yes. Selectable marker gene which is often an antibiotic resistance gene

Question 5.
2nd PUC Biology Question Bank Chapter 11 Biotechnology Principles and Processes 5
Study the linking of DNA fragments shown above
(i) Name “a” DNA and “b” DNA
(ii) Name the restriction enzymes that recognize this palindrome
(iii) Name the enzyme that can link these two DNA fragments (CBSE 2008)
Answer:
(i) (a) – vector DNA
(b) – foreign DNA

(ii) EcoRI
(iii) DNA ligase

Question 6.
Explain the importance of
(a) Ori
(b) amp R and
(c) rop in E. Coli vector shown below (CBSE 2008)
Answer:
2nd PUC Biology Question Bank Chapter 11 Biotechnology Principles and Processes 6

  • Ori – Origin of replication
  • amp R – ampicillin antibiotic resistance gene
  • rop – gene that produces proteins involved in the replication of plasmid.

Question 7.
An interesting property of restriction enzymes is molecular cutting and pasting Restriction enzymes typically recognize a symmetrical
2nd PUC Biology Question Bank Chapter 11 Biotechnology Principles and Processes 7
Notice that the top strand is the same as the bottom strand but reads backward. When the enzyme cut the strand between G and A, it leaves overhanging chains
2nd PUC Biology Question Bank Chapter 11 Biotechnology Principles and Processes 8
(A) What is the symmetrical sequence of DNA known as?
(B) What is the significance of these overhanging chains?
(C) Name the restriction enzyme that cuts the strand between G and A.
Answer:
(A) Palindromic sequence
(B) sticky ends
(C) Eco RI

Question. 8.
What is DNA ligase?
Answer:
DNA ligase is a specific type of enzyme, a ligase that facilitates the joining of DNA strands together by catalyzing the formation of a phosphodiester bond.

Question 9.
What are cloning vectors? What functions do these vectors perform?
Answer:
Cloning vectors are those organisms on their DNAs which can multiply independently of the host DNA and increase their copy number along with the alien DNA attached to them. Functions are:

  • They help in linking the foreign/alien DNA with that of the host
  • They also help in the selection of recombinants from non-recombinants

Question. 10.
What is Ti-plasmid?
Answer:
Ti or tumor-inducing plasmid is a plasmid that is a part of the genetic equipment that Agrobacterium tumefacient use to transduce their genetic material to plants.

Question 11.
Palindromic nucleotide sequences have significance in recombinant DNA technology. Explain. Give example for a palindromic DNA sequence.
Answer:
Palindrome in a DNA is a sequence of base pairs that reads same on the two strands when orientation of reading is kept the same. Each restriction endonuclease recognises a specific palindromic nucleotide sequence and cuts the strand of DNA a little away from the centre of the palindrome site, but between the two bases on the opposite strands.
Example of palindrome DNA is
5′ – GAATTC – 3′
3′ – CTTAAG – 5′

Question. 12.
Name the scientist who discovered the artificial DNA synthesizing method.
Answer:
The Nobel prize in physiology in 1968 was awarded jointly to Robert W. Holley, Hargobind Khorana, and M. Nirenberg for their interpretation of the genetic code.

2nd PUC Biology Biotechnology: Principles and Processes Three Marks Question

Question 1.
Given below are the different steps in recombinant DNA technology. Arrange them according to the sequence of occurrence.
a. Transferring the recombinant DNA into the host.
b. Extraction of the product.
c. Fragmentation of DNA by restriction endonucleases
d. Ligation of DNA fragment into a vector.
e. Isolation of DNA.
f. Culturing the host ceils in a medium at large scale.
g. Isolation of the desired DNA fragment.
Answer:
a. Isolation of DNA.
b. Fragmentation of DNA by restriction endonucleases
c. Isolation of the desired DNA fragment.
d. Ligation of DNA fragment into a vector.
e. Transferring the recombinant DNA into the host.
f. Culturing the host cells in a medium at large scale.
g. Extraction of the product.

KSEEB Solutions

Question 2.
Represent diagrammatically the E Coli cloning vector pBR 322 showing the restriction site.
Answer:

2nd PUC Biology Question Bank Chapter 11 Biotechnology Principles and Processes 9

Question 3.
Draw a labelled diagram of a sparged stirred tank bioreactor.
Answer:
2nd PUC Biology Question Bank Chapter 11 Biotechnology Principles and Processes 10

Question 4.
Read the following base sequence of a certain DNA strand and answer the questions that follow.
2nd PUC Biology Question Bank Chapter 11 Biotechnology Principles and Processes 11
(i) What is called “Palindromic sequence” in a bNA?
(ii) Write the Palindromic nucleotide sequence shown in the DNA strand given and mention the enzyme that will recognise such a sequence.
(iii) State the significance of enzymes that identify palindromic nucleotide sequences.
(AI – 2008)
Answer:
(i) A palindromic sequence of DNA is a sequence of base pairs that reads the same on the two strands, when orientation of reading is kept the same, i.e. in the 5′ → 3′ direction.
(ii) 5′ GAA TT C – 3′
3′ CTTA AG – 5′
This sequence is restricted by the restriction enzyme Eco RI
(iii) The enzyme that identifies the palindromic nucleotide sequence cuts the strands between the same 2 bases, more often producing sticky ends; hence they are useful in the formation of recombinant DNA.

2nd PUC Biology Biotechnology: Principles and Processes Five Marks Question

Question 1.
Describe in detail the components of a simple stirred tank bioreactor along with a labeled diagram.
Answer:
A stiered tank bioreactor is usually a cylindrical vessel with a curved base to facilitate the mixing of the content. The stirrer facilitates even mixing and oxygen availability throughout the bioreactor.
2nd PUC Biology Question Bank Chapter 11 Biotechnology Principles and Processes 12

The bioreactor has an agitator system, an oxygen delivery system along with a foam control system, a temperature control system, pH control system and sampling ports to remove small volumes of culture periodically. It provides optimum growth conditions of pH, temperatures, substrate, oxygen etc. for achieving the desired products.

Question. 2.
What is a clone? Give its preparation, extracted and purified.
Answer:
An organism or cell or group of organisms, produced asexually from an ancestor, to which they are genetical.

1. Gene cloning: Following steps are used by gene cloning:

1. Preparation of gene: DNA extracted from an organism, with the gene of interest is cut into gene size pieces with a restriction enzyme.

2. Insertion into a vector: Bacterial plasmids are cut with the same restriction enzyme. Plasmids are small circles of DNA in bacterial cells that are naturally present in addition to the bacterial other DNA.

3. Transformation of host cells: The recombinant plasmids are then transferred into bacteria using either electrophOration. The plasmid is small enough to pass through the holes into the cells. However, rather than using electricity to create holes in the bacterium, it is done by alternating the temperature between hot and cold. The bacteria are grown on a culture dish and allowed to grow into colonies. All the colonies on all the plates are called a gene library.

2. Plant cloning: Plant tissue culture is a method of propagation that has been sprouting in popularity as an alternative to cloning.

The plant can be cloned artificially using tissue culture. Vegetative propagation works because the end of the cutting forms a mass of nonspecialized cells called a callus, the callus will grow divide and form various specialized cells eventually forming a new plant.

KSEEB Solutions

Question 3.
(a) If the restriction enzyme has to cut a DNA, the DNA must be in pure form, i.e. free from the associated RNA and proteins. How is it achieved?
(b) Represent only diagrammatically the steps in the recombinant DNA (r DNA) technology.
Answer:
(a) The RNAs are removed by using enzymes called ribonucleases (RNases) The proteins are removed by using enzyme proteases.
(b)
2nd PUC Biology Question Bank Chapter 11 Biotechnology Principles and Processes 13

Question 4.
(a) Show only diagrammatically the three steps in the polymerase chain reaction,
(b) How is repeated amplification achieved using this method?
Answer:
2nd PUC Biology Question Bank Chapter 11 Biotechnology Principles and Processes 15
(b) Repeated amplification is achieved by the use of a thermostable DNA polymerase, it is isolated from the bacterium Thermus aquaticus. It remains active during the high temperature used for denaturation of the double-stranded DNA.

Question 5.
Make a diagrammatic representation of showing a restriction enzyme, the substrate DNA on u which it acts the site at which it cuts DNA and the product it produces.
Answer:
2nd PUC Biology Question Bank Chapter 11 Biotechnology Principles and Processes 16

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