Biotechnology : Principles and Processes Class 12
Chapter 11 Biotechnology : Principles and Processes Exercise Solutions
Exercise : Solutions of Questions on Page Number : 205
Can you list 10 recombinant proteins which are used in medical practice? Find out where they are used as therapeutics (use the internet).
Recombinant proteins are obtained from the recombinant DNA technology. This technology involves the transfer of specific genes from an organism into another organism using vectors and restriction enzymes as molecular tools.
Ten recombinant proteins used in medical practice are -
Recombinant protein |
Therapeutic use |
||
1. |
Insulin |
Treatment for type I diabetes mellitus |
|
2. |
Interferon-α |
Used for chronic hepatitis C |
|
3. |
Interferon -β |
Used for herpes and viral enteritis |
|
4. |
Coagulation factor VII |
Treatment of haemophilia A |
|
5. |
Coagulation factor IX |
Treatment of haemophilia B |
|
6. |
DNAase I |
Treatment of cystic fibrosis |
|
7. |
Anti-thrombin III |
Prevention of blood clot |
|
8. |
Interferon B. |
For treatment of multiple sclerosis |
|
9. |
Human recombinant growth hormone |
For promoting growth in an individual |
|
10. |
Tissue plasminogen activator |
Treatment of acute myocardial infection |
|
|
|
||
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.
The name of the restriction enzyme is Bam H 1.
From what you have learnt, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?
What would be the molar concentration of human DNA in a human cell? Consult your teacher.
The molar concentration of human DNA in a human diploid cell is as follows:
⇒ Total number of chromosomes x 6.023 x 1023
⇒ 46 x 6.023 x 1023
⇒ 2.77 x 1018 Moles
Do eukaryotic cells have restriction endonucleases? Justify your answer.
Besides better aeration and mixing properties, what other advantages do stirred tank bioreactors have over shake flasks?
The shake flask method is used for a small-scale production of biotechnological products in a laboratory. On the other hand, stirred tank bioreactors are used for a large-scale production of biotechnology products.
Stirred tank bioreactors have several advantages over shake flasks:
(1) Small volumes of culture can be taken out from the reactor for sampling or testing.
(2) It has a foam breaker for regulating the foam.
(3)
Collect 5 examples of palindromic DNA sequences by consulting your teacher. Better try to create a palindromic sequence by following base-pair rules.
The palindromic sequence is a certain sequence of the DNA that reads the same whether read from 5' → 3' direction or from 3' → 5' direction. They are the site for the action of restriction enzymes. Most restriction enzymes are palindromic sequences.
Five examples of palindromic sequences are:
Can you recall meiosis and indicate at what stage a recombinant DNA is made?
Can you think and answer how a reporter enzyme can be used to monitor transformation of host cells by foreign DNA in addition to a selectable marker?
Describe briefly the followings:
(b) Bioreactors
Answer :
(a) Origin of replication -Origin of replication is defined as the DNA sequence in a genome from where replication initiates. The initiation of replication can be either uni-directional or bi-directional. A protein complex recognizes the 'on' site, unwinds the two strands, and initiates the copying of the DNA.
(b) Bioreactors - Bioreactors are large vessels used for the large-scale production of biotechnology products from raw materials. They provide optimal conditions to obtain the desired product by providing the optimum temperature, pH, vitamin, oxygen, etc. Bioreactors have an oxygen delivery system, a foam control system, a PH, a temperature control system, and a sampling port to obtain a small volume of culture for sampling.
(c)
Explain briefly
(b) Restriction enzymes and DNA
Answer :
(a) PCR: - Polymerase chain reaction (PCR) is a technique in molecular biology to amplify a gene or a piece of DNA to obtain its several copies. It is extensively used in the process of gene manipulation. The process involves in- vitrosynthesis of sequences using a primer, a template strand, and a thermostable DNA polymerase enzyme obtained from a bacterium, called Thermus aquaticus. The enzyme utilizes building blocks dNTPs (deoxynucleotides) to extend the primer. In the first step, the double stranded DNA molecules are heated to a high temperature so that the two strands separate into a single stranded DNA molecule. This process is called denaturation. Then, this ssDNA molecule is used as a template strand for the synthesis of a new strand by the DNA polymerase enzyme and this process is called annealing, which results in the duplication of the original DNA molecule. This process is repeated over several cycles to obtain multiple copies of the rDNA fragment.
(b)
Restriction enzyme are categorized into two types -
(i) Exonuclease - It is a type of restriction enzyme that removes the nucleotide from either 5' or 3' ends of the DNA molecule.
(ii) Endonuclease - It is a type of restriction enzyme that makes a cut within the DNA at a specific site. This enzyme acts as an important tool in genetic engineering. It is commonly used to make a cut in the sequence to obtain DNA fragments with sticky ends, which are later joined by enzyme DNA ligase.
(c)
Discuss with your teacher and find out how to distinguish between
(b) RNA and DNA
Answer :
(a) Plasmid DNA and chromosomal DNA
Plasmid DNA |
Chromosomal DNA |
Plasmid DNA is an extra-chromosomal DNA molecule in bacteria that is capable of replicating, independent of chromosomal DNA. |
Chromosomal DNA is the entire DNA of an organism present inside chromosomes. |
(b) RNA and DNA
RNA |
DNA |
|
1. |
RNA is a single stranded molecule. |
DNA is a double stranded molecule. |
2. |
It contains ribose sugar. |
It contains deoxyribose sugar. |
3. |
The pyrimidines in RNA are adenine and uracil. |
The pyrimidines in DNA are adenine and thymine. |
4 |
RNA cannot replicate itself. |
DNA molecules have the ability to replicate. |
5 |
It is a component of the ribosomes. |
It is a component of the chromosomes. |
(c) Exonuclease and Endonuclease
|
Exonuclease |
Endonuclease |
|
It is a type of restriction enzyme that removes the nucleotide from 5' or 3' ends of the DNA molecule. |
It is a type of restriction enzyme that makes a cut within the DNA at a specific site to generate sticky ends. |
||
|
|
||