Genetic Technology, practice questions

B, Genetic engineering directly alters genes in the laboratory and can transfer a gene between very different species, unlike selective breeding.

B, The gene is inserted into a bacterial plasmid, forming recombinant DNA that is then returned to a bacterium.

B, A plasmid is a small circular piece of bacterial DNA used as a vector to carry a transferred gene into a host cell.

B, Bt cotton carries a gene from a soil bacterium that makes it produce a toxin effective against a specific pest caterpillar.

C, Fermentation by yeast is a traditional biotechnology process that has been used for centuries without any gene transfer.

B, Gene therapy inserts a working copy of a gene into targeted cells or tissues to replace or support a faulty gene.

C, DNA fingerprinting compares unique DNA patterns to identify a person or confirm a biological relationship, without changing any gene.

B, Reproductive cloning produces a whole new organism genetically identical to the original, such as the sheep Dolly.

C, Each genetically modified crop is tested and regulated individually, based on the specific gene it carries and its observed effects.

B, Recombinant DNA is formed deliberately using specific enzymes to cut a gene from one source and join it into DNA from another source.

• (a) The human gene that codes for insulin is cut out of human DNA using a specific enzyme.
• The gene is inserted into a bacterial plasmid using another enzyme, forming recombinant DNA.
• The recombinant plasmid is returned to a bacterium, which is allowed to reproduce under controlled conditions.
• As the bacteria multiply, each one reads the human gene and produces human insulin, which is collected and purified.
• (b) This method produces insulin in much larger, more reliable quantities and does not depend on extracting the hormone from animal organs.

• (a) Applications include crops modified for resistance to a specific pest, and crops modified for tolerance of a particular herbicide.
• (b) Bt cotton carries a gene from a soil bacterium that makes the plant produce a natural toxin effective against a specific pest caterpillar.
• This reduces the need for chemical pesticide spraying to protect the crop.
• (c) Each genetically modified crop carries a different inserted gene chosen for a different purpose.
• Its safety and effects depend on that specific gene rather than on the general fact of being genetically modified.

• (a) Reproductive cloning produces a whole new individual organism, genetically identical to the original, such as the sheep Dolly.
• Therapeutic cloning instead aims to produce matching cells or tissue for medical treatment, without creating a new organism.
• (b) One benefit is that genetic technology allows cheaper, more reliable production of medicines such as insulin.
• One concern is the unknown long-term effect of a genetically modified organism on other species in the environment, such as an inserted gene spreading to a wild relative of a crop.
• A balanced answer states both points and briefly explains why each matters, rather than presenting only one side.

Genetic engineering is the deliberate, direct alteration of an organism's genes in the laboratory, most often by transferring a useful gene from one organism into another so the recipient gains a new characteristic it did not have before. This differs from selective breeding, which only works with genetic variation that already exists in a population. The transferred gene can come from a bacterium, a plant or an animal, and it is moved across species boundaries for a specific purpose.

Recombinant DNA is formed by cutting a gene from one source and joining it into DNA from another, often a bacterial plasmid, using specific enzymes. Once inserted into a host cell, the recombinant DNA is copied and read along with the host's own genes. The plasmid acts as a vector, a carrier that ferries the new gene into the host and allows it to be copied whenever the host cell divides.

Practical applications include bacteria engineered to produce human insulin and growth hormone, crops modified for pest resistance, herbicide tolerance or improved nutrient content, and enzymes engineered for use in industrial processes such as detergents and food production. Each application starts from the same basic technique: identifying a useful gene, then transferring and expressing it in a new host. Bt cotton, for example, is engineered to produce a natural toxin against a specific pest caterpillar, making it one of the most widely grown genetically modified crops in the world.

Biotechnology is the broader use of living organisms, cells or their products for a practical purpose, and includes traditional processes such as fermentation for bread and yoghurt alongside modern techniques such as genetic engineering and enzyme technology used at an industrial scale. Genetic engineering can therefore be described as one modern branch within the wider field of biotechnology, not a separate subject.

Benefits include cheaper, more reliable production of medicines such as insulin and vaccines, higher and more resilient crop yields that support food security, and new treatments for some genetic diseases through approaches such as gene therapy. Industrial enzymes produced through biotechnology can also make manufacturing processes faster and use less energy.

Concerns include unknown long-term effects of a genetically modified organism on health or on other species in the environment, unequal access to expensive new technology between rich and poor countries, and broader questions about how far it is acceptable to alter living things. A strong exam answer names a specific concern, such as an inserted gene spreading to a wild relative of a crop, rather than describing the worry in general terms.

Gene therapy treats a genetic disease by inserting a working copy of a gene into a patient's cells to replace or support a faulty one. It targets specific cells rather than the whole body, so it does not automatically change every cell or get passed on to the patient's children. Research in this field is still active, and the number of widely approved gene therapy treatments remains small compared with conventional medicine.

A genetically modified crop has had a useful gene inserted, for example for resistance to a specific pest or tolerance of a herbicide, or for higher levels of a nutrient. Each GM crop is tested and regulated individually rather than judged as automatically safe or unsafe as a category.

DNA fingerprinting compares the pattern of repeated DNA sequences that is unique to each individual, other than identical twins, to identify a person or establish a biological relationship. It does not involve changing any genes, only reading and comparing patterns that already exist. Close relatives share more of these patterns than unrelated people, which is what makes the technique useful for paternity testing.

Cloning produces a genetically identical copy of an organism or of specific cells. Reproductive cloning creates a whole new individual, as with the sheep Dolly, while therapeutic cloning aims to produce matching cells or tissue for medical treatment rather than a new organism. Because a clone shares the same genes as the original, it does not automatically share every observable characteristic, since environment also plays a part.