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Biotechnology: Principles and Processes - Principles of Biotechnology

Grade 12CBSEBiology

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Biotechnology is defined by the European Federation of Biotechnology (EFB) as the integration of natural science and organisms, cells, parts thereof, and molecular analogues for products and services.

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Genetic Engineering: Techniques to alter the chemistry of genetic material (DNADNA and RNARNA), to introduce these into host organisms and thereby change the phenotype of the host organism.

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Bioprocess Engineering: Maintenance of sterile (microbial contamination-free) ambience in chemical engineering processes to enable growth of only the desired microbe/eukaryotic cell in large quantities for the manufacture of biotechnological products like vaccines, enzymes, etc.

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The three basic steps in genetically modifying an organism (GMO) are: (i) Identification of DNADNA with desirable genes; (ii) Introduction of the identified DNADNA into the host; (iii) Maintenance of introduced DNADNA in the host and transfer of the DNADNA to its progeny.

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Origin of Replication (oriori): A specific DNADNA sequence responsible for initiating replication. Any piece of DNADNA, when linked to this sequence, can be made to replicate within the host cells.

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Restriction Enzymes: Also known as 'molecular scissors', they cut DNADNA at specific sequences. For example, EcoRIEcoRI recognizes the sequence 5′−GAATTC−3′5'-GAATTC-3'.

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Construction of first rDNArDNA: Stanley Cohen and Herbert Boyer (1972) isolated an antibiotic resistance gene by cutting out a piece of DNADNA from a plasmid of SalmonellaSalmonella typhimuriumtyphimurium and linked it to a plasmid vector using DNADNA ligase.

📐Formulae

Nomenclature of Restriction Enzymes: Genus (Capital)+species (2 lowercase)+strain+Roman numeral (order of discovery)\text{Nomenclature of Restriction Enzymes: Genus (Capital)} + \text{species (2 lowercase)} + \text{strain} + \text{Roman numeral (order of discovery)}

Total number of DNA copies after n cycles of PCR=2n\text{Total number of DNA copies after } n \text{ cycles of PCR} = 2^n

Cell growth in Bioprocess Engineering: N=N0ert\text{Cell growth in Bioprocess Engineering: } N = N_0 e^{rt}

General structure of a Palindromic Sequence: 5′→3′ sequence is identical to 3′→5′ sequence on the complementary strand\text{General structure of a Palindromic Sequence: } 5' \rightarrow 3' \text{ sequence is identical to } 3' \rightarrow 5' \text{ sequence on the complementary strand}

💡Examples

Problem 1:

Identify the palindromic sequence for the restriction enzyme EcoRIEcoRI and indicate where the cut is made.

Solution:

The sequence is 5′−GAATTC−3′5'-GAATTC-3' on one strand and 3′−CTTAAG−5′3'-CTTAAG-5' on the complementary strand. The enzyme cuts between GG and AA on both strands.

Explanation:

Restriction endonucleases inspect the length of DNADNA and bind to specific recognition sequences. EcoRIEcoRI cuts the DNADNA between the same two bases (GG and AA) only when the sequence GAATTCGAATTC is present in the 5′5' to 3′3' direction.

Problem 2:

How many copies of a specific DNADNA segment will be produced after 3030 cycles of the Polymerase Chain Reaction (PCRPCR)?

Solution:

230≈1092^{30} \approx 10^9

Explanation:

In PCRPCR, the number of DNADNA molecules doubles with every cycle. Therefore, the formula used is 2n2^n, where nn is the number of cycles. After 3030 cycles, approximately 11 billion (one billion) copies are generated.

Problem 3:

If a piece of DNADNA is inserted within the gene for β\beta-galactosidase, what happens to the colony color of the bacteria on a chromogenic substrate?

Solution:

The colonies will appear white (colorless).

Explanation:

This is known as Insertional Inactivation. The presence of the insert disrupts the coding sequence of the enzyme β\beta-galactosidase. As a result, the bacteria cannot produce the enzyme to break down the chromogenic substrate, and the colonies do not turn blue.

Principles of Biotechnology - Revision Notes & Key Diagrams | CBSE Class 12 Biology