Biotechnology

What is biotechnology?

Biotechnology refers to the artificial tools and techniques used on organisms or the products of organisms to make a product or solve a problem for human benefit

What are the tools used in DNA-base biotechnology?

Restriction enzymes, ligase, polymerase, primer

What is the role of restriction enzymes in biotechnology?

Restriction enzymes are enzymes that cut DNA molecules at recognition sites.

What is the role of ligase in biotechnology?

Ligase is an enzyme that seals/reassembles DNA fragments in the process of ligation. It sticks the backbone together.

What are the techniques used in DNA-based biotechnology?

Amplification, annealing, PCR and gel electrophoresis

What is amplification?

Amplification is used to greatly increase the number of copies of a DNA sequence for further laboratory use. This can be achieved by either inserting the sequence into a cloning vector that replicates within a host cell, or by PCR.

What is annealing?

Annealing is the process of joining two pieces of DNA by complementary base pairing (joining of overhanging sticky ends). The two pieces are joined by weak hydrogen bonds only, and hterefore only temporarily.

What is PCR?

Polymerase chain reaction is a cyclic method used to rapidly amplify relatively small numbers of particular sequences of DNA into a large number of copies.

What are the requirements of PCR?

Requirements are template DNA, taq polymerase, buffer solution to maintain pH, a supply of the four nucleotides, two sets of single-stranded DNA primers.

What are the steps in PCR?

Denaturation, annealing, extension and then repeating all the steps.

What is denaturation step in PCR?

Denaturation is done at 95°C. This is where the double stranded DNA is heated breaking the weak hydrogen bonds between complementary bases, causing the two template strands to separate.

What is annealing step in PCR?

Annealing is done at 50–60°C. This is where the single stranded DNA primers anneal to complementary sequences on the ends of each strand. Primers attach to complementary base-pairing rules.

What is the extension step in PCR?

Extension is done at 72°C. Extension is where DNA taq polymerase extends the new strand, starting from primers. New DNA strands are synthesised using taq polymerase and available nucleotides. At the end of this phase, there are two copies of each original strand of the double-stranded DNA. The DNA has doubled at the end of this step.

What are plasmids?

Plasmids are a small circular DNA molecule found in bacteria.

How are plasmids used in the creation of genetically modified organisms?

The gene of interest is identified and isolated. Then the plasmid is cut at a specific site (using restriction enzymes). The gene of interest is inserted into plasmid, and recombinant DNA is formed.

What is a vector?

Vector is a DNA molecule that transports genetic material into another cell/host cell.

What is gel electrophoresis?

Gel electrophoresis is a technique that can separate large charged molecules according to size and charge, so that they can be visualised and identified by comparison with a standard.

How can DNA profiling help identify genetic makeup?

DNA profiles can be visualised using gel electrophoresis. Different individuals of the same species will generate unique banding patterns. Individuals who are homozygous or heterozygous have allele bands of different sizes.

What is DNA sequencing?

• DNA sequencing refers to the methods and technologies used to determine the orders of the nucleotide bases in a DNA molecule.

• It works by cutting DNA into fragments to sequence on section at a time.

• The entire set can then be put together to create a whole genome.

• Knowing the sequences can help scientists determine the genetic code for particular phenotypes, and there may be survival benefits.

How does the sanger sequencing method work?

The terminated strands line up from smallest to largest. The various colour enable identification of the nucleotide in each position.

How are DNA identification technologies applied in agriculture?

• DNA identification technologies can be used to accurately trace the genetics of desirable traits and to acquire these traits within a generation.

• This enables us to increase the availability and quality of food for the growing human population.

• Using marker-assisted breeding, plant scientists can examine the DNA of seeds to find the ones that will produce the best plants.

What is transformation?

Transformation is taking a gene from one species and inserting it into another to obtain a desired characteristic.

What is the use of biotechnology in environmental conservation?

Uses include monitoring endangered species, assessing gene pools for breeding programs and quarantine.

What are potential adverse effects of transgenic organisms?

• effects on non-target organisms

• more rapid evolution of pesticide-resistant species

• possibility of gene flow from crop species to weed species

• reduction of genetic diversity in crop plants

Arguments for biotechnology

• biotechnology is natural as genetic engineering has existed for years, such as farmers breeding specific cattle to achieve the desired traits, biotechnology is an extension of this process.

Arguments against biotechnology

• biotechnology is not natural as selective breeding only involves individuals from the same species, yet biotechnology is transferring genes across species, which rarely happens naturally

Arguments for genetically engineered foods with respect to public health

• biotechnology can vastly improve the health, nutritional value and growth capacity of agriculture species, can help to combat a global food crisis

• there are strict guidelines that aim to ensure all genetically engineered is as safe as non-genetically engineered food

Arguments against genetically engineered foods with respect to public health

• selective breeding has provided us with crop improvements in the past and can be a source of steady improvement in crop quality

• the long term effects of genetic modification of crops are essentially unknown