Biotechnology

Step 1: Understanding the Concept:
The Indian Government established the Genetic Engineering Appraisal Committee (GEAC) under the Ministry of Environment, Forest and Climate Change.
It acts as a regulatory body to oversee activities involving the use, manufacture, storage, export, and import of hazardous microorganisms or genetically engineered organisms and cells.
Step 2: Detailed Explanation:
The primary responsibilities of GEAC include:
1. Validity of Research: Making decisions regarding the validity and safety of genetic engineering research.
2. Public Safety: Assessing the safety of introducing genetically modified (GM) organisms into the public domain for services (e.g., GM crops for agriculture).
3. Environmental Impact: Evaluating the potential risks posed by GM organisms to the environment and biological diversity.
Step 3: Final Answer:
GEAC expands to Genetic Engineering Appraisal Committee.
Its responsibility is to regulate the use of genetically modified organisms and ensure the safety of introducing them for public use.

Step 1: Understanding the Concept:
Large-scale production of biological products requires specialized equipment to maintain optimal conditions.
Step 2: Detailed Explanation:
Shake flasks are used for small-scale laboratory experiments and cannot handle volumes greater than a few liters effectively.
Stirred-tank bioreactors (100–1000 liters) are designed for large-scale production.
They provide better aeration (oxygen transfer), uniform mixing, and precise control over temperature, pH, and foam, which is essential for high yields of recombinant proteins.
Step 3: Final Answer:
False.

Step 1: Understanding the Concept:
Restriction enzymes follow a specific nomenclature based on the bacterial source from which they are isolated.
Step 2: Detailed Explanation:
For the enzyme EcoRI:
The first letter 'E' comes from the genus Escherichia.
The next two letters 'co' come from the species coli.
The letter 'R' is derived from the name of the specific strain, which is RY 13.
The Roman numeral 'I' indicates the order in which the enzyme was discovered or isolated from that strain.
Step 3: Final Answer:
The letter 'R' in EcoRI represents the strain of the organism.

Step 1: ELISA is a biochemical technique used mainly in immunology to detect the presence of an antibody or an antigen in a sample.
Step 2: It is based on the principle of antigen-antibody interaction.
Step 3: It is commonly used as a diagnostic tool for diseases like AIDS (caused by HIV).

Step 1: Understanding the Concept:
Insulin is synthesized in mammals as a pro-hormone (proinsulin) that requires processing to become a functional mature hormone.
Step 2: Detailed Explanation:
Proinsulin consists of three chains: A-peptide, B-peptide, and a connecting C-peptide.
Mature functional insulin consists only of A and B chains linked together by disulphide bridges.
During the maturation of proinsulin into insulin, the C-peptide is enzymatically removed.
This is why mature insulin does not contain the C-peptide.
Step 3: Final Answer:
The C-peptide is removed during the maturation process of insulin.

Step 1: BT Toxin - Bacillus thuringiensis ( ) produces protein crystals during a specific phase of their growth which contain a toxic insecticidal protein.
Step 2: Mode of Action - When a caterpillar ingests the toxin, it is converted into an active form due to the alkaline of the insect's gut.
Step 3: Effect - The activated toxin binds to the surface of midgut epithelial cells and creates pores, causing cell swelling and lysis, which eventually leads to the death of the insect. This technology is used to create -Cotton.

Step 1: Understanding the Concept:
Genetic engineering requires "molecular scissors" (restriction enzymes) and "molecular glue" (DNA ligase).
Step 2: Detailed Explanation:
1. The Palindrome: Restriction enzymes recognize a "Palindromic Nucleotide Sequence"—a sequence that reads the same on both strands in the direction (e.g., GAATTC).
2. The Staggered Cut: Most restriction enzymes (like EcoRI) do not cut exactly in the middle of the palindrome. They cut the two strands slightly apart from each other.
3. Sticky End Formation: This results in short, single-stranded "tails" of DNA hanging off the ends. Because these tails have exposed bases, they are "sticky" (ready to base-pair with a complementary sequence).
4. The Joining Process:
- If both the source DNA and the vector DNA are cut with the same enzyme, their sticky ends will be perfectly complementary.
- They naturally find each other and form weak Hydrogen bonds.
- The enzyme DNA Ligase then makes the bond permanent by forming a covalent phosphodiester bond between the sugar and phosphate of the adjacent nucleotides.
Step 3: Final Answer:
Sticky ends are staggered cuts made by restriction endonucleases that facilitate the precise annealing of DNA fragments, which are then covalently sealed by DNA ligase.

Step 1: Understanding the Concept:
Bacillus thuringiensis is a soil bacterium that naturally produces protein crystals during a specific phase of its life cycle. These crystals contain the "Cry" (Crystal) protein.
Step 2: Detailed Explanation:
1. Mechanism of Toxicity:
- The protein is produced as an inactive protoxin in the bacterium (this ensures the bacterium itself isn't killed).
- When an insect (like a bollworm) eats the plant, the protoxin enters its gut.
- The alkaline pH of the insect's midgut solubilizes the crystal and activates the toxin.
- The active toxin binds to the midgut lining, creating pores. This causes cell swelling and lysis, eventually starving and killing the insect.
2. Biotechnological Exploitation:
- Scientists isolated the specific genes (cry genes) from the bacteria.
- They inserted these genes into the DNA of crop plants (e.g., Bt-Cotton, Bt-Corn).
- Now, the plant produces its own pesticide.
3. Benefits to Farmers:
- Reduced dependency on expensive chemical pesticide sprays.
- Protection of beneficial insects that would normally be killed by broad-spectrum sprays.
- Higher crop yields due to reduced pest damage.
Step 3: Final Answer:
Cry proteins are natural biopesticides. By transferring the genes responsible for these proteins into crops, scientists have created plants that can defend themselves against specific insect pests.

Step 1: Understanding the Concept:
Because DNA is negatively charged and hydrophilic, it cannot cross lipid-rich cell membranes naturally. Host cells must be specifically treated to force them to take up recombinant DNA.
Step 2: Detailed Explanation:
1. Chemical Treatment: The bacterial cells are treated with a specific concentration of a divalent cation, such as calcium ( ). This increases the efficiency with which DNA enters the bacterium through pores in its cell wall.
2. Incubation: Recombinant DNA is incubated with the host cells on ice.
3. Heat Shock: The cells are then placed briefly at (heat shock) and then put back on ice.
4. Result: This series of steps allows the bacteria to take up the recombinant DNA.
Step 3: Final Answer:
Host cells are made competent by treating them with ions and applying a heat-shock treatment, which alters membrane permeability.

Step 1: Understanding the Concept:
After a transformation experiment, only a very small percentage of bacterial cells actually take up the foreign DNA. Scientists need a way to find those specific cells.
Step 2: Detailed Explanation:
1. Identification: A selectable marker is a gene (usually an antibiotic resistance gene like ampR or tetR) that allows researchers to distinguish between cells that have taken up the vector and those that have not.
2. Selection: Non-transformed cells will die in the presence of the selective agent (antibiotic), while transformed cells will survive and multiply.
3. Efficiency: Without a selectable marker, it would be impossible to isolate the few successful recombinant cells from millions of unsuccessful ones.
Step 3: Final Answer:
Selectable markers are vital for the selective growth of transformed host cells and for eliminating non-transformed cells during the screening process.